Update on Diet-Associated Dilated Cardiomyopathy

Last week brought a revealing announcement from the FDA. After frequent and persistent petitioning from Veterinarians, Veterinary Nutritionists, and concerned Caregivers, the FDA finally released a list of the brands that have been linked to cases of diet-associated dilated cardiomyopathy (DCM). Since June 27, my inbox and social media sites have been blowing up with shares, retweets, and emails from concerned friends and family. The story was even picked up by major news outlets, like CNN and ABC, adding to the fervor.

But I’m conflicted about this report. On one hand, certain pet food manufacturers have taken a very cavalier approach to their diet’s role in this preventable and potentially deadly disease. Because only a relatively “small percentage” of dogs develop diet-associated DCM on their foods, they insist that there is no problem, ignoring the overwhelming evidence to the contrary.  On the other hand, the FDA’s report paints a broad stroke over specific brands and is being interpreted (at least by the concerned friends and owners I’ve talked to) as an indictment of all “grain-free” or of certain manufacturers, which is a less than helpful oversimplification of a complex problem. As I advised in my post last fall (and this bears repeating here) I would urge caution before panicking and rushing to change your dog or cat’s food without considering what to change to. By all means if you are feeding a diet that has been associated with heart disease in other dogs then a change is warranted, but before jumping to another potentially problematic diet (just because it is not on the list) it is important to step back and look at what we know and don’t know to date.


Not a diet-associated DCM case, but could have been if we didn’t get him on the right diet for his breed and health status.

Recap of the Problem …

In 2017 Veterinary Cardiologists began noticing an increased incidence of DCM in Golden retrievers. This is a breed (along with other large breed dogs) with an increased risk of DCM in general, but the number of cases and age at onset of disease was not typical. This prompted a closer look at potential contributing factors and Veterinary Cardiologists then reached out to the larger veterinary community for information on other cases of unexpected or atypical DCM in any dog. Initially, the common thread was the feeding of a diet marketed as “grain-free.” Since that time the FDA Center for Veterinary Medicine (FDA-CVM) and researchers at both Tufts University and University of California, Davis, Veterinary Schools have been collecting data and working on finding a root cause of this potentially fatal disease. They have found that not only were Veterinarians seeing cases of DCM in dogs fed diets marketed as “grain free”, but also in dogs eating diets that use uncommon animal proteins (like kangaroo and bison, whether grain-inclusive or not) or that were made by smaller manufacturers that may or may not be adequately formulated for long-term feeding.

From the FDA update June 27, 2019.

So what do we know?

  1. Not all cases are taurine deficient. Many of the dogs diagnosed with diet-associated DCM in the last 2 years had low taurine levels, but not all. Whether low or normal taurine levels were measured, most dogs if caught early had improvement in clinical signs and reversal of cardiac changes when their previous diet was stopped and taurine was supplemented.
  2. Not all dogs eating “grain-free” diets are affected. There are an estimated 20 million dogs eating diets marketed as “grain-free” that include some combination of legumes (peas, lentils, chickpeas, pinto, etc.) or potato (sweet or white), or both, and only (only?!) 515 reported cases of diet-associated DCM in dogs since 2017.
  3. Large breed dogs are at an increased risk, but even small dogs are affected. Large breed dogs account for 338 out of the 515 reported cases, but Shih tzus and Shetland Sheepdogs are on the list, too.
  4. Dry dog foods are the predominant type reported, but raw and home-cooked make the list, too. This probably has more to do with the relative popularity of these diet types rather than some inherent risk/benefit of a particular food type.
  5. “Grain-Free” is a marketing ploy and not based on any scientific or nutritional studies. There is no proven health benefit to avoiding grains in your dog’s diet unless they have a documented food allergy (which is actually very uncommon). Grains play a lot of roles in the diet, and most of these roles are pretty helpful at optimizing health.

Meeting with Dr. Weeth to make sure we are keeping our hearts and whole bodies healthy.

What don’t we know?

  1. We don’t know the true scope of the problem. In people, underreporting of adverse drug effects is a well-known problem with some reviews indicating that as high as 95% of adverse reactions go unreported. Which means we may be seeing only the  5% of actual cases that were reported to the FDA and it could be closer to 10,000 dogs that are affected. It takes time to report a suspected adverse food event and Veterinarians and Caregivers may not realize the value of this reporting. Additionally, many owners may contact the pet food manufacturer if there is a problem rather than the FDA assuming that the information is getting relayed to the government agency.
  2. We don’t know where the problem is coming from. All grain-free diets are being targeted by media outlets and some enthusiastic pet “advocates”, but we don’t know if this is a problem with all grain-free diets (probably not), peas and legumes (maybe, especially at high amounts), and/or questionable formulations and manufacturing processes (probably, yes). When peas are included at relatively low levels in the diet (less than 20% of the total recipe) or as occasional treats they do not appear to cause a problem, but none of the diets from any of the brands on the FDA’s recent list have gone through controlled feeding and digestibility trials to prove that they are safe and healthy for dogs at the level of legume inclusion they use, which can be over 40% of the recipe when all types and portions are added up.
  3. We don’t know if this is an ingredient, dog, or manufacturer problem (or maybe all three). I suspect we will find that peas and potatoes in the hands of experienced formulators and experienced pet food manufacturers and for the majority of dogs are not the problem. The problem will be (like it was in the early 2000s when poorly formulated lamb and rice dog foods were causing DCM in dogs) a failure of certain manufacturers to account for variation in ingredient quality, changes in digestibility with processing, and individual variation in the dog population. Do affected dogs have low taurine production? Do they have increased loss from their gut? Do they have normal production and gut handling, but a low total food intake and are just getting inadequate intake overall? Meeting minimum nutrient levels on paper is not enough. Pet food manufacturers must know or hire knowledgeable individuals with an understanding for how nutrient levels vary in the raw materials, how they are affected by other ingredients or nutrients in the mix, the effect of cooking (or lack of cooking) on nutrient stability and bioavailability, and the wide range of variability in genetics and food intakes in the dog population. Basing diet formulations on market trends rather than nutritional science is a recipe for disaster.
  4. We don’t know if the percentages of the brands reported simply represent their popularity and market share or an underlying problem with these companies.  Maybe the three most frequent brands reported are really no better or worse than the least frequent three brands, they are just better at marketing their diets so more people buy them. I don’t have access to those market insights to know whether this is true or not, but I bet these companies do.

At the end of the day, diet-associated DCM is a preventable condition and manufacturers who are selling foods that are labeled as “complete and balanced” have an ethical and fiduciary obligation to meet that label promise. Having an idea about pet foods, being a dog trainer/breeder/owner, inheriting a family pet-food business, and/or writing a book about dogs and cats (even if it’s about food) does not qualify a person to know what it takes to keep a large population of dogs and cats healthy. No free passes because you didn’t know what you didn’t know, no matter the sincerity, especially if it ends up with disease and death.

And if you are a Veterinarian who is seeing cases of suspected diet-associated DCM or are a Caregiver with a dog or cat who has been diagnosed with suspected diet-associated DCM, please report it by following the link here so we can help the FDA get to the bottom of this problem before more dogs and cats get sick.


Dr. Weeth keeping dogs and their hearts healthy!

Happy (and Safe) Feeding,


Dr. Weeth


Hearts and Health: What Caregivers Need to Know About Diet-Induced Dilated Cardiomyopathy (DCM)

#1: Don’t Panic

Panic leads people to do things that seem reasonable in the heat of the moment, but may not be well thought out or reasoned and could have negative long-term consequences. Deciding that “all grains are evil” and embracing food fads is what got us here in the first place. If you are feeding a diet that is marketed as “grain-free” and it includes a number of newer pet food ingredients, such as chickpeas and lentils, and your dog appears otherwise normal at home (no changes to behavior, activity, appetite or stool quality) then take a deep breath and make an appointment to talk to your primary care veterinarian before changing the diet, because…

First Step: Talk to your veterinarian.

#2: Not all grain-free diets seem to be affected.

We (as in the larger veterinary community) are still in the early stages of figuring out exactly what is causing the recent cases of diet-induced DCM. We do know that not all diets that are marketed as “grain-free” are affected and that not all dogs or cats eating these types of diets go on to develop DCM. There was a recent webinar addressing this health problem and the three guest speakers (a veterinarian from the FDA, a PhD Veterinary Nutritionist who has been working with members of the pet food industry for decades, and a DACVN and PhD Veterinary Nutritionist who is probably the world-leader on nutrition and heart health) laid out the details of what we know to date. According to the FDA representative, they have received 149 reports of diet-induced DCM that include a total of 160 dogs and 8 cats (some of those affected are in multi-animal households, which only get counted as 1 report), with 39 dog deaths and 1 cat death attributed to this condition. If your dog or cat developed this preventable disease then any illness or death is an illness or death too many, but considering that at least as of 2015 pet foods marketed as grain-free accounted for about 1/3 of pet food sales in the US and are being fed exclusively to an estimated 20 million dogs and cats in the United States according to information presented on the FDA webinar, these cases would represent 0.00084% of the nation’s pet population being fed grain-free diets. Put another way that is fewer than 9 dogs and cats per 1 million dog and cats being fed grain-free diets as their sole source of nutrition and spread over the entire country. In all likelihood this problem is probably under-reported, but even if actual cases are 4x what has been reported that is still 0.0034% of the pet population eating grain-free foods. Don’t get me wrong, that number should be ZERO animals developing diet-induced DCM, but we need to keep some perspective. This problem has probably also been occurring since the onset of the grain-free pet food trend began 8 years ago, but it wasn’t until sales volume hit a critical threshold that a small percentage of animals having a problem with this type of diet became a larger percentage of the cases being seen by Veterinary Cardiologist that anyone began to notice. When it hit the mainstream media earlier this year, caregivers and the larger veterinary community began to take notice, too, but …

Some we need a change in perspective to see what is in front of us.

#3: Diet-induced DCM is not a new problem, unfortunately.

The first article confirming diet-induced DCM in cats was published in 1987 and a good overview of this condition in cats was published a few years later in 1992; taurine deficiency was identified as a contributing factor to DCM in Cocker Spaniels in 1997, in dogs fed low protein diets in 2001, and in a family of Golden Retrievers in 2005; and taurine-deficient canine DCM was seen in large breed dogs in the late 90s and early 2000s when these dogs were being fed certain commercial lamb and rice-based dry dog foods. The diet-induced DCM cases on lamb and rice diets spawned a number of additional studies and a sampling of them can be found here, here, and here.  Larger companies and knowledgeable formulators knew about this potential problem and adjusted their formulas and recipe accordingly. Meaning if the pet food company was around in the early 2000s when the most recent wave of diet-induced DCM was seen or if it is a newer company that worked or continues to work with a Veterinary Nutritionist (either PhD or DACVN) and followed their advice on how to formulate and what to supplement, then the diet you are feeding is probably just fine, grain-free or not. But if you are concerned that your dog or cat’s diet might be a problem …

When in doubt, check it (blood taurine that is) out.

#4: Testing blood taurine levels is easy.

I am a huge advocate for preventative medicine in our dogs and cats. Our furry companions can look “healthy” from the outside and be harboring pretty bad disease on the inside. A number of my posts over the last few years are a testament to that. There are certain minimally invasive tests like blood draws or urine collection that can identify early stages of disease when diet, supplement, or medication intervention can have the most significant impact on health and longevity. If you are concerned about your dog’s (or cat’s) taurine status you can have your veterinary clinic collect blood samples and send them to the UC Davis Amino Acid Lab for analysis. The outside laboratories that veterinary clinics and hospitals use (Idexx and Antech) will also accept samples, but they are mostly just a conduit to UCD (for an additional handling fee) so I typically ship direct. Either way will work and if every dog eating a grain-free diet had whole blood and plasma taurine levels run it might help the researches get closer to a specific cause or causes for the current diet problems. Speaking of which, does everyone know that …

#5: Not all DCM is created equally.

Right now there are three categories of affected animals that veterinarians and researchers are seeing.

  • Breeds that are genetically predisposed to DCM irrespective of diet, such as Golden Retrievers, Doberman Pinschers, Newfoundland, Portuguese Waterdogs, Irish Wolfhounds, and Cocker Spaniels. These breeds have an even higher risk of DCM if fed “high risk” diets. What were considered high-risk diets before the latest grain-free trend, you ask? Diets low in total protein; diets that included protein sources low in sulfur amino acid precursors (such as lamb-based, rabbit-based, and vegetarian or vegan diets); diets that are high in fiber that increases loss of taurine through the gut; or a combination thereof.
  • Taurine-deficient DCM in atypical breeds. This and the third type of diet-induced DCM are the current areas of active interest. It is not clear if diets that are marketed as “grain-free” have other characteristics that are decreasing the bioavailability of taurine precursors (which are methionine and cysteine), or are changing gut bacterial populations to ones that basically chew up the taurine before it can get reabsorbed by the dog, or if there are anti-nutritive factors in the diet or individual ingredients that irreversibly binding taurine and prevent absorption/reabsorption. What we have seen is that companies supplementing both DL-methionine AND taurine or ones that have high inclusions of animal proteins and relatively low inclusions of plant-based proteins appear not to be involved with this problem, at least that we’ve seen so far.
  • Diet-induced DCM not associated with taurine deficiency. This is the one that seems to be stumping researchers. According to the panel of experts on the September 4 webinar a small percentage of reported diet-induced DCM cases are in dogs that have normal plasma and whole blood taurine levels, but have still improved when the diet was changed and/or taurine was supplemented. This could be related to correcting of a relative deficiency in other essential nutrients with the diet change. An example of another non-essential in the diet, but essential for health, nutrient is carnitine.  Like taurine, carnitine is essential for heart health, but unlike taurine, it also relies on another essential amino acid, lysine, for biosynthesis. Interestingly, lysine can be limiting in commercial pet foods in part due to the formation of Maillard reaction products. The Maillard reaction is the cross-linkage of lysine and sugars in the diet that occurs with heating (i.e. cooking) of a food that creates a physical browning reaction; it imparting a caramel color to cooked foods and a number of the aromas and flavors that make baked, roasted and grilled foods so tasty, but binding of lysine makes it unavailable for the animal.

Maillard products, eat them up, yum!

The Take-Home Message

If your pup is seemingly healthy, doesn’t have any energy or appetite changes at home, and there are no clinical signs of disease on exam (no murmur or arrhythmia, normal ECG, no abnormal finding on a 3 view chest xray) then they can either stay on the current diet (assuming good quality manufacturer that is supplementing with any potentially limiting nutrients) or continue with a more complete workup including whole blood and plasma taurine levels and an echocardiogram before deciding the diet’s fate. It is not wrong to run whole blood and plasma taurine levels on a dog that seems “normal” from the outside and is on what appears to be a well-balanced diet if it gives everyone peace of mind, but it may not be necessary in all cases. Then once all test results are in you can decide whether a diet change is in order.

I don’t have a preference for brands or ingredients that caregivers feed (but please no raw!) as long as all of the essential nutrient needs of your dog or cat are being met and that diet is improving health and wellness. The field of veterinary nutrition has 50+ years of knowledge on how dogs and cats digest and metabolize whole grains, such as wheat, corn, rice, and barley, so unless your dog or cat has a specific allergy or intolerance to a particular whole grain, there is no reason to avoid them.

Happy (and Safe) Feeding!

Dr. Weeth and Miss Penny

In Defense of Grains

I like to think of myself as a moderate in all things veterinary nutrition. Avoid known toxins, avoid any particular food or ingredient that your individual dog or cat does not seem to tolerate, feed a balanced diet in an amount to maintain a healthy body condition, and try not to tie your pet food choices to someone else’s ethical eating standards.  Especially with the recent attention on grain-free diets, it is important for caregivers to understand when market trends, rather than animal nutrition, are shaping their dog or cat’s diet.

Be smart like Penny and educate yourself about pet food marketing.

So where did the idea that grains are somehow bad come from?

Simple. It came from pet food companies that were trying to distinguish themselves in a competitive marketplace. It had nothing to do with quality, food safety or nutrition and all about selling pet food.

Corn and other whole grains somehow became the “wrong” foods to feed dogs and cats about 10 years ago. My personal theory was that this shift in pet food ingredients was a combination of: 1) the pet food recalls in 2007 due to  contaminated wheat and rice ingredients;  2) an increased awareness of “hidden allergens” in people foods starting in 2004 when labeling laws for people foods required human food manufacturers to start listing all potential food allergens whether intentionally added or not; 3) the availability and promotion of what was then a new category of plant ingredients, the pulses (i.e., peas and other legumes), starting in 2010; and 4) smaller pet food marketing companies trying to make a name (and a lot of money) by distinguishing themselves from the established competition.


We grow a LOT of delicious corn in the middle.

Companies big and small like to highlight the differences between their foods and their competitor’s products, something that has been done from the beginning of food marketing times. Since the vast majority of over-the-counter dog and cat foods were and still are largely manufactured in the Midwest where corn and wheat are grown and easy to get at a good price point, smaller companies that targeted pet owners willing to pay more for their pet food began using less common and more costly pet food ingredients like potato and peas.  The problem with the explosion in sales of grain-free pet food is that these ingredients are relatively new to the pet food marketplace and don’t have the decades of feeding trials and nutrient and digestibility standards to demonstrate that they are safe for long-term, chronic feeding.

Everyone loves Porkchop and her side of corn.

This Nutritionist’s quasi-concern with corn.

I don’t have any concerns about corn as a stand-alone food or ingredient in pet foods. Corn is high in the essential-for-life omega-6 fatty acid linoleic acid (LA) so it makes balancing home-cooked diets easier, but is also practically devoid of the essential-for-optimal-skin-health omega-3 fatty acid alpha-linolenic acid (ALA) so by itself isn’t a complete food. ALA was not recognized as a nutrient requirement until publication of the National Research Council’s Nutrient Requirements for Dogs and Cat book in 2006 and it still hasn’t been incorporated into the AAFCO Model Bill and Guidelines for pet food manufacturers. Meaning diets that are made by manufacturers who use large amounts of corn (high in LA and variable digestibility depending on quality standards of the manufacturer) that don’t follow new developments in the field of dog and cat nutrition can legally sell diets that are listed as “complete and balanced” that are potentially imbalanced in essential fatty acid levels and may cause dull dry skin, itching and flaking and excessive shedding in some animals. This isn’t an “allergy” to corn, or even an indication that corn is bad, but that the essential fatty acids in that diet aren’t balanced for that individual dog or cat’s needs.


Not all itches are fleas and allergies.

What about gluten?

Gluten is just the generic term for protein found in plants. People with celiac disease are sensitive to the specific glutens found in wheat, rye and barley called gliadin and glutenin, but have zero problems with the gluten found in rice or corn. There is some evidence that Irish setters and soft coated wheaten terriers may have similar gliadin and glutenin sensitivities, but this condition has not been seen or proven in cats or other dog breeds. The disconnect with pet foods is that from a legal labeling perspective  “gluten” is the generic food science definition of a plant protein (i.e., rice gluten, wheat gluten, corn gluten) and is what shows up on labels even though the physical structures of each of these plant proteins are all unique. Over the last decade, small and medium-sized pet food marketing companies have started to exploit peoples lack of awareness of these differences to demonize all grains in pet foods in order to sell more of their own “grain-free” products.

Raider was sweet and adorable, though his beef- and flea-allergy dermatitis were not.

What about dogs and cats with grain allergies?

The majority of the gastrointestinal food sensitives that I see and treat in dogs and cats are not true allergies. True allergies are eosinophil mediated type III hypersensitivity reaction resulting from an antigen-antibody complex that triggers a cascade of immune-mediated problems resulting in inflammation and dysfunction of the skin or intestinal tract. If your dog or cat has an allergy to any given ingredient then absolutely avoid that ingredients, but what I tend to see are mostly adverse food reactions caused from feeding poorly digestible diets or ingredients that alter gastrointestinal microflora causing bacterial dysbiosis (imbalance of “good” vs “bad” bacteria that are normal inhabitants of the intestinal tract). It is these bacterial-induced changes on the environment in the digestive tract that affect its function (nutrient absorption and holding poop until the appropriate time and place) that cause the signs that can keep dogs, cats, and their caregivers up at night (literally and figuratively).

What are the benefits of including whole grains in a diet?

Grains like barley, wheat, rice and corn provide essential nutrients like protein, amino acids (the building blocks of protein), +/- the essential omega-6 fatty acid linoleic acid (essential for skin and coat health), vitamins like thiamin and riboflavin (B1 and B2), and minerals like magnesium and selenium. They also provide a source of dietary fiber and while fiber is not considered “essential for life” and is not included in the AAFCO nutrient list for dog and cat diets, is actually essential for normal intestine health and function. As I’ve written before in this blog, fiber, especially fermentable fibers feed the gut bacteria that feed the colon cells and keep them happy and healthy. And there it is one thing that we can all agree on is that eyes are the windows to the soul and poop is the herald of health.

Playful Penny loves all foods and has the healthiest poops of any dog she known.

The bigger picture on grains …

We grow a lot and eat a lot of grains and cereal crops in the United States whether as individual ingredients or fractions of ingredients (think rice flour and soy protein). These are less expensive sources of nutrients than animal proteins so companies who are trying to reduce costs and maximize profits (which is ALL OF THEM) will use easily sourced plant-based ingredients whenever possible. The last 50+ years of commercial pet food production has shown us that these foods are safe and nutrition sources of nutrients for dogs and cats when processed and stored correctly. Corn, wheat, sorghum, barley, and rice have been used successfully for decades in dog and cats foods, they are palatable and digestible by both dogs and cats, but, depending on the amount and quality of the plant-based ingredients digestibility may not be great and since digestibility is inversely related to poop volume:  more digestible = less poop; less digestible = more poop.

If your individual dog or cat has a known sensitivity to any particular ingredients (plant or animal sourced) then absolutely avoid that particular food in your individual dog or cat’s diet. This is also true if that dog or cat is sensitive to chicken, emu, elk, or quinoa. Dogs and cats can develop sensitivities or allergies to any protein, whether it comes from a plant or an animal. I realize all of these statements make me unpopular among certain self-appointed pet food advocacy groups and individuals, but aside from foods that contain known toxins or are harmful to dogs and cats, there is no one perfect diet or set of ingredients for each individual dog or cat.


Happy Feeding!

Lisa P. Weeth, DVM, MRCVS, DACVN

Pet Food Basics: Dr. Weeth’s Top Tips for Feeding Your New Dog

Just after school let out this June we welcomed a new four-legged member of the family. This was Penny the day we adopted her…

Me and Penny Day 1

Me and Penny adoption day

Penny is now an almost 5-month-old Shepherd mix (mom was a 50 lb Shepherd mix and dad was who-knows-what). She is practically perfect in every way and is probably the cutest, smartest puppy in the world (or at least as far as our little family’s world is concerned) and like all new puppy parents, I want to give her the best start in life. That means taking her for regular check-ups, making sure she is socialized (once fully vaccinated) and learns good canine citizen skills, brushing her teeth daily, and feeding her a good quality food for her breed combination and life-stage.



Penny’s First Vet Visit

Penny got her puppy check-up and vaccines with a veterinarian other than me (it has been a few years since I’ve been in a General Practice setting so I defer to the GP experts to help me keep her healthy), we picked up a few puppy and dog training books months ago (in anticipation of adding a puppy to the mix), and our new GP showed the kids how to start brushing Penny’s teeth (more info at avdc.org ) so we are off to a good start. My specialty training in nutrition so I feel pretty comfortable making diet decisions for her on my own, but with so much conflicting and sometimes questionable recommendations out there I wanted to put together a list of what I am calling “Weeth’s Top Tips” to help you keep your very own pup healthy and happy for years to come whether you have a recent addition or a stable pack.



Penny’s First Trip to the Beach

Weeth’s Top Tip #1: Feed Puppies Puppy Food

I know it sounds pretty obvious, but make sure the diet you are feeding to your new puppy is designed and formulated for feeding to puppies. I’ve seen rescue groups, breeders, and online personalities recommend feeding adult dog food to “slow” the puppy’s growth. Don’t do this. Puppies have higher requirements for just about every essential nutrient (protein, essential fatty acids, vitamins, and minerals) so we want to make sure we give them the right start in life. “Slowing” a puppy’s growth by feeding an adult maintenance food is called “malnutrition”.

Weeth’s Top Tip #2: Check Your Labels

Commercial pet foods no matter the size of manufacturer are required by law to have a Feeding Statement on the label that indicated that the diet is either “complete and balanced”, “intermittent or supplemental feeding only”, or “use as a treat”. More on labels can be found here and here. You want a diet that is labeled to have specifically been formulated or undergone feeding trials either for “growth and maintenance” or “all life stages”. If there is no Feeding Statement at all on the label put it down and walk away. This is technically an illegal label, and if the company marketing the food doesn’t know basic label requirements what else don’t they know? If it is labeled for “intermittent feeding” or as a “treat” then only give it intermittently or as a treat making up less than 10% of your puppy/dog’s daily calorie intake. If the Feeding Statement says “for adult maintenance only” wait until your puppy is at least 80% of their adult size to transition to this food.


Bigger, but still not big enough for adult dog food.

Weeth’s Top Tip #3: Feed for Your Breed

Always, and I mean always, feed your large or giant breed puppy a diet developed specifically for large or giant breed puppies. The level of calories, calcium (an essential mineral necessary for bone growth among other things), and the calcium-to-phosphorus ratio (the level of these two essential minerals relative to one another) should be controlled in the diet for large and giant rapidly growing dogs. Overnutrition (i.e., overfeeding) and excess calcium intake don’t typically cause developmental bone and joint disease in small and medium breeds (though excess calories can still lead to obesity and joint disease down the line), but these can be a serious health risk in large and giant breed growing puppies.  If large and giant breed puppies are overfed and grow too quickly their bones and joints can’t physically keep up; too little calcium and the bones become weak and fragile and can break as the puppy grows and jumps around as puppies do; too much calcium and the extra is deposited in the bone preventing normal remodeling and bone growth. This is partially related to their physical size (larger puppies have more mechanical force on their developing bones and joints) as well as how much time they spend in the active “puppy growth” phase. A small breed dog with an expected adult size of less than 20 lb will reach 80% of its expected adult size by about 9 months of age, whereas in a large breed puppy with an adult size of 55-90 lb it is closer to 12 months, and a giant breed (90 lb+) may not reach 80% of its adult size until closer to 15-18 months of age. More months of growth means more months where things could go wrong if the diet isn’t balanced for their needs.

puppy vs adult dog

Feed for breed and life-stage

Weeth’s Top Tip #4: Feed for Body Condition

All puppies go through stages of growth where they seem to grow out (i.e., get pudgier) before they grow up (i.e., get taller) so brief periods of excess puppy fat aren’t a concern to me, but if your puppy is constantly in the rolly-polly phase they may be getting too many calories overall. Waltham just released a puppy growth chart kit with a handy smartphone app (that is unfortunately only available through the UK App Store currently) that can help vets and caregiver track growth. Hopefully, the US version is on its way to the App Store, but until then I can track Penny on a printed version of the chart below. And in case you were wondering what an “ideal” body condition would be there is a handy chart you can print off of the World Small Animal Veterinary Association (WSAVA) website and share with the whole family, especially the one that likes to give treats.

WSAVA dog BCS chart

One of the “tools” of my trade

Weeth’s Top Tip #5: Store You Pet Food in Its Original Container

Not a nutrition tip specifically, more of a food safety tip. Bulk bins and fancy dog food containers for dry kibble look very pretty on Pinterest, in a housewares catalog, or in the pet supply boutique, but I would advise against using them and instead have you keeping the food in its original packaging for three big reasons.

  • Big Reason For Original Packaging #1: Dry pet food packaging of today is designed to keep your dog or cat food fresher than any plastic, stainless steel or glass bulk bin container. Innovations in package technology help keep the nutrients in, and the elements (and pests) out.
  • Big Reason For Original Packaging #2: These bulk bins are nearly impossible to clean, which means old food residues are getting mixed with the new food you add in. Imagine if you reused the same cereal bowl each morning without washing between uses. For years.
  • Big Reason For Original Packaging #3: If there are ever any questions about or problems with the food, you won’t have the necessary barcodes and product identifiers to report back to the pet food company or the FDA-CVM (just in case you need to bookmark how to report food concerns to the FDA-CVM click here. Recalls happen (though hopefully with much less frequency going into the future. Thank you FSMA!) and if it happens with your selected brand of pet food, you absolutely want to have the original packaging. If you need a secondary container to keep your puppy or dog, or even another human or non-human animals from ripping a hole in the bag, then use a bulk bin, but leave the food in the original packaging and put it in, bag and all.
bag in bulk bin

If you need to keep it safe from critters, keep it in the bag!

Happy and Healthy Feeding!


Dr. Weeth (and Penny)


Pentobarbital in Pet Food: What is it and how does it get there?

In light of the most recent pet food recall I wanted to take a little time to talk about a chemical that has popped up in not one but two recent pet food recalls: Pentobarbital.


There’s what in where?!?!

Let’s start with “What is Pentobarbital?” Pentobarbital is a drug that in low doses can cause sedation and drowsiness and in high doses can cause respiratory failure and death. Its primary use in veterinary medicine is as a euthanasia solution for all types of animals and it is not an approved ingredient in pet foods and is considered an illegal “adulterant” in pet food.

What’s in Place To Stop It From Actually Getting Into Pet Food? According to the USDA regulations for human foods, any “Product found to contain violative levels of residues is considered adulterated and is subject to condemnation”. Meaning meat or meat products that have drug residues or potentially deleterious (to people) compounds are condemned and prevented from entering the human food supply. That does not mean that it automatically goes into pet foods though.  The AAFCO Model Bill and Guidelines used for pet food manufacturing reference the United States Code and the Code of Federal Regulations of the Food and Drug Administration Sec. 402 [342] to help ensure pet food ingredient quality and safety.

The actual wording of the FDA regulation …


Sec. 402 [342]

A food shall be deemed to be adulterated –

(a) Poisonous, insanitary, etc., ingredients

(1) If it bears or contains any poisonous or deleterious substance which may render it injurious to health; but in case the substance is not an added substance such food shall not be considered adulterated under this clause if the quantity of such substance in such food does not ordinarily render it injurious to health”

Because Pentobarbital is considered a compound that is “injurious to health” even at low levels animals euthanized with Pentobarbital are not allowed to be used in pet food manufacturing.

So How Could It Get Into Pet Food?? In the United States, food animals (cattle, pigs, sheep, and goats) must be healthy enough to walk into a slaughter facility and any animal that is unable to walk (is “down”) or shows signs of illness must be individually inspected and cleared before and after slaughter to ensure that it is safe for the human food supply. FYI – just about everything in pet food is considered a “by-product” of the human food supply chain so human health safety is always the first check-point. For any of my really keen readers, more information about USDA animal inspections can be found here. Animals that are not healthy enough for traditional slaughter methods (ironic I know) can be humanely euthanized (i.e. injected with Pentobarbital) and their remains segregated to prevent them from getting into any food supplies. And again, Pentobarbital is not an approved ingredient in pet foods and is considered an illegal “adulterant”, so the short answer is that it shouldn’t.

So How Did It Get There??? The only way for detectable levels of Pentobarbital to be found in pet foods is through inclusion of animals (animals plural, as in probably more than one) that were killed by use of this euthanasia solution. A survey of dry dog foods sold in the Maryland area and published in 2002 by FDA-Center for Veterinary Medicine (CVM) found low levels of Pentobarbital in some of the foods tested, but it was in the part per billion (ppb) not percentages (% = parts per hundred). The levels in the dog foods tested  were well below what would be considered acutely toxic or harmful to dogs, but because of the concern that chronic low dose exposure could become harmful if ingested daily for years, many pet food manufacturers (including Big Pet Food) began testing for and excluding animal products with detectable Pentobarbital levels.

You Didn’t Answer the Question, How Did Pentobarbital Get Into the Food???? That I don’t know for sure, but the FDA-CVM released a statement today on their preliminary finding related to the first recall. It looks like the raw beef supplier was using a slaughter facility that was not following USDA protocols. If we combine that with an absence of quality and safety testing from the manufacturer or raw material supplier on that raw beef as it come in, then we have the perfect combination of safety failures to result in potential harm to our companion dogs and cats.

How Can I Trust My Pet Food?????  All of the large and many of the medium to small-sized pet food manufacturers have regular and enforced Quality Control standards.  Mistakes happen, but if the pet food/treat manufacturer has established and enforced Hazard Analysis Critical Control Point (HACCP) and Food Safety Modernization Act (FSMA) protocols in place a situation like this would have been found and prevented before the contaminated meat found its way into the pet food supply. These types of manufacturing checks and balances are designed to keep our companion animal’s (and our own) food safe, but they only work if the companies involved uses and enforces them. If a pet food manufacturer does not conduct any inspection or testing of the raw materials they receive, that manufacturer is relying on the integrity of their raw material supplier to provide the ingredients ordered. If that raw material supplier is in turn not routinely inspecting or testing animal products from the slaughterhouses and rendering facilities they work with then nobody in that pet food company really knows what is going into the foods that bare their name.

There are companies big and small out in the pet food marketplace that have a commitment to health and wellness, not just profit. Those pet food manufacturers are committed to producing high-quality pet foods and will inspect and test their raw materials before they are mixed into a food and will sample and test the finished products before and after they go to market. It is important to know not only who makes your dog or cat’s food, but also if they are doing it the right way.


Gratuitous cat picture, because cats.

Happy Feeding!





Your Pet’s Pancreas and You

Ah, the pancreas… an often overlooked and misunderstood part of the digestive system that only gets noticed by veterinarians and caregivers when it’s not working well.  But the pancreas shouldn’t just get attention when it is inflamed and painful (from Pancreatitis), or not producing enough insulin (from Diabetes Mellitus), it deserves recognition for doing its job well and not causing problems on a day-to-day basis. Today’s post is to familiarize you with the pancreas and (hopefully) give you a few tips to help you keep it happy for years to come.


Happy Pancreas = Happy Dog

Anatomy of the Pancreas

This part gets a bit technical, so bear with me. The pancreas is a glandular organ that sits behind the stomach and extends across the length of the stomach to the upper small intestinal (the duodenum). It connects to the duodenum via the pancreatic duct, which serves at the pathway for release of digestive enzymes and other essential compounds into the intestinal tract. This part of the pancreas’ job is called its exocrine function. This is in addition to the pancreas’ other, probably more familiar role, the production and release of insulin into the blood stream (i.e., its endocrine function). The endocrine pancreas will be covered in my next post on Diabetes Mellitus; I’m not completely ignoring that topic, just pushing off for now.

Pancreatic enzyme release is triggered by the hormone cholecystokinin (CCK) that is secreted from the intestinal cells in response to the intake of certain food components, specifically protein and fat. Both protein and fat will stimulate CCK release, but fat has a much more pronounced effect even at lower intakes. Irrespective of trigger, the secretion of CCK causes the pancreas to contract and squeeze pancreatic enzymes down the pancreatic duct and into the duodenum to begin the breakdown of dietary macronutrients (macronutrients = dietary protein, fat and carbohydrate). There are a few other functions of CCK, such as stimulating contraction of the gall bladder and creating a feedback on the brain to slow food intake, but it’s CCK’s effect on the pancreas that I am focusing on for management (and minimization) of pancreatitis.

knitted digestive tract

Your key digestive organs, without the actual blood and guts

The Exocrine Pancreas

The primary exocrine enzymes produced by the pancreas are trypsin and chymotrypsin (both used for protein digestion), lipase (required for fat digestion), and amylase (essential for starch digestion). These enzymes are produced in their inactive forms, which must be activated by other enzymes in the presence of bicarbonate (also made in the pancreas). For example, trypsin is actually made and stored in the pancreas as trypsinogen. Trypsinogen is packaged into zymogen granules within the pancreas and kept separate from bicarbonate. This isolation of enzymes and activators protects both the integrity of the digestive process and the pancreas itself.  If trypsin becomes activated too early not only will it not get into the duodenum where it is needed for food digestion, but it will start to digest the proteins in the pancreas instead. And this is painful. Very, very painful.

Sparky PN

One of my former patients on IV nutritional support, fluid support and pain meds because of severe pancreatitis.


What Causes Inflammation of the Pancreas?

The clinical name for inflammation in the pancreas is pancreatitis (pancreas- = pancreas + -itis = inflammation). Pancreatitis can either be acute (vomiting and pain within hours) or chronic (low smoldering illness with vague signs that can be confused with other medical conditions).

In dogs, one of the most common dietary causes of acute pancreatitis is eating a non-food item (like 2 lb of bird seed) or eating fatty table scraps (either intentionally fed or found by rooting through the garbage). The exact mechanism of pancreatitis isn’t known but it is believed that the higher than normal fat intake causes the rapid increase in circulating blood fats and then “activation” of pancreatic enzymes within the pancreas. Other risk factors for acute pancreatitis include being a miniature Schnauzer or Yorkshire terrier (sorry pups), or any other dog breed that has a genetic predispositions to hypertriglyceridemia (the term for high circulating levels of triglyceride in the blood); being on medication such as potassium bromide and phenobarbital (two common anti-seizure medication); and being more than 20% over your ideal weight (yep, being a fat dog isn’t a cosmetic issue). Chronic pancreatitis in dogs is a bit more challenging to identify as the clinical signs can be vague and are often confused with other chronic medical conditions, because of this chronic pancreatitis is thought to be an under-diagnosed and under-reported condition. One study out of the UK conducted post-mortem evaluations of 200 dogs that had died from a variety of different causes (none of which were reported to be either acute or chronic pancreatitis in the medical records by the way) and found evidence of chronic pancreatitis in one-third of them.

Cats on the other hand like to be different. Genetics, medications, obesity, and high fat meals are not often associated with pancreatitis in cats. Instead stressful events, like introduction of a new animal into the household or having work done at your home, seem to be the more common histories among cats that present to their veterinarian with signs of acute pancreatitis. Many of these cats may also be diagnosed with what veterinarians like to call triaditis, (triad- = three + -itis = inflammation), meaning they are found to have evidence of inflammation in the pancreas (pancreatitis), in the liver (hepatitis), and in the intestinal tract (enteritis) all at the same time. Chronic pancreatitis can also be seen along with diabetes mellitus in cats, though just like with triaditis it often becomes a chicken-or-the-egg game to figure out which came first.


What Does Pancreatitis Look Like?

Animals, both dogs and cats, with mild cases of pancreatitis may vomit, refuse food, or seem quieter than usual at home. Dogs and cats with chronic, low-grade pancreatitis may have vague signs such as an intermittently poor appetite and weight loss. Severe pancreatitis can cause not only vomiting, food refusal, and lethargy, but diarrhea, fever, and abdominal pain. Severe pancreatitis, if left untreated, can also result in shock, circulatory collapse, and death. So pancreatitis is basically badness, followed by more and more severe badness if not caught and treated.


Signs of pancreatitis aren’t always obvious. 



What Can We Do About It?

Supportive treatment for dogs and cats with pancreatitis is very similar: IV fluids to keep them hydrated, anti-nausea meds to stop them from vomiting, and pain control (whether they are acting overtly painful or not) will be on the list. Dietary therapy on the other hand is less consistent so here is where I’d like to provide some general guidelines to caregivers, vet techs, and veterinarians when treating dogs and cats with known or suspected pancreatitis.

The two most important features of a diet for an animal with pancreatitis are (in order of important): 1) feeding a diet that is LOWER in fat than what was being fed before and 2) feeding a diet that is MORE digestible than what was fed before. If you don’t know what is causing the GI signs you’re seeing and you have pancreatitis as one of the possible causes on the list, err on the side of caution and just feed a lower fat, more digestible diet. Seems straight forward but I see a lot of confusion in practice about how to translate this to an actual diet so I give you…


Dr Weeth’s Dietary Consideration for Feeding Animals with Pancreatitis

dog and food bowl

What is in that bowl is as important as the rest of the medical treatment

  1. Dietary fat is a wonderful thing for healthy animals, except when it’s not. Fat can enhance the palatability of the food (I much prefer half and half in my coffee to skim milk); in the right amounts and with the right fatty acid profile can improve coat glossiness and decrease shedding (and big dogs can shed a lot!); fat also provides more calories per gram than either protein or carbohydrates, so feeding a higher fat diet relative to a moderate or low fat diet will increase energy density, reducing the overall volume of food needed each day; and with this reduction in volume in, so, too, do you see a reduction in the volume of poop coming out. The end result of feeding a higher fat food is often that the dog or cat readily eats their food, has a lovely shiny coat, doesn’t shed very much, and has a low stool volumes. Sounds perfect (and a lot like the reasons people give for feeding raw … hhmmm… maybe it’s not the “raw” part of those diets that is doing anything?…). Perfect unless you are a dog or cat with pancreatitis. When the pancreas is inflamed dietary fat can stimulate CCK release, contraction of the pancreas and release of digestive enzymes… into the pancreas. This promotes continued autodigestion of the pancreas and surrounding tissues, malabsorption of nutrients, and pain. Cats and dogs with abdominal pain can be very stoic, but if you or a human loved one has experienced pancreatitis you know it is not fun. Fat is sometimes your friend, but sometimes your dog or cat’s worst enemy.
  1. Digestibility is important for everyone. In general, over-the-counter (OTC) adult maintenance dog and cats food will be less digestible than the therapeutic intestinal support diets sold by veterinarian. This means that more of the OTC diet you feed (yes, even the “premium” priced ones) becomes poop rather than getting absorbed by your dog or cat. There is some variability in OTC diets and a number of the newer “premium” marketed foods, especially ones that are frozen/freeze-dried raw or fresh pasteurized, can be as digestible as intestinal support diets. BUT, before you think that sounds like a great option for animals with pancreatitis, many OTC diets (especially “premium” marketed foods), will have fat contents that exceed 50% of the calories in the diet. These types of diet would be very harmful for a dog with a history or an active case of pancreatitis. OTC diets marketed as “light” or “lean” will have lower fat contents compared to standard adult maintenance foods, but as the fat dropped in OTC diets, so does the digestibility. What about home-cooked foods you may ask? Some combinations of home-prepared foods, like cottage cheese and white rice or chicken breast and white rice, can be as digestible, if not more digestible, than the therapeutic intestinal support diets, but there is going to be a lot more variability depending on the way they are cooked and specific ingredients selected. Also, many home-prepared diets are rarely balanced for long-term feeding ( and if used should only be fed during the recovery stages of pancreatitis (about 2-3 weeks) before your dog or cat is transitioned to a balanced diet whether it is a commercial diet or you have the home-prepared foods balanced for long-term feeding.
  1. Diet History is key to finding the right diet the first time around. Whenever possible the decision of what to feed and the degree of fat restriction needed should be based on the previous diet intake. This is where diet and treat history are very important. Did your dog (that lovable furry fiend) get into the BBQ remains or a container of bacon grease you’ve been meaning to throw out? In these types of case your dog could have eating a whoppingly high fat intake and as such feeding a moderate fat contenting diet (one that provides between 20-35% fat calories) would be fine. Or did they develop pancreatitis or hyperlipidemia, or both, while eating a diet that was already at 25% fat calories? In this situation, feeding a diet with a similar fat content would not help, and could potentially make them worse. These dogs should be fed a diet that provides less than 20% of the calories from fat. Basically, you want to find out how much fat the dog is eating now and decease it by about half while still staying above the minimum requirement for fat. As I mentioned earlier, cats are a bit different and you want to find a diet that manages whatever concurrent medical conditions your veterinarian finds. Fat triggers and subsequent fat restriction are less important in most cases, but (and I feel like there is always a but) this is not true 100% of the time. I have definitely seen cats in practice that acted more like fat-responsive pancreatitic dogs and needed to fed a highly digestible, fat restricted diet.


The optimal long-term diet choice for a dog or cat with pancreatitis will depend on the inciting cause (genetics, medication, hypertriglyceridemia, or high fat intake) and additional medical issues (diabetes mellitus, IBD, etc). Irrespective of underlying cause, dogs with a history of pancreatitis should never be fed diets or treats with more than 45% of the calories coming from fat due to the risk of recurrent pancreatitis.


Happy and Healthy Feeding!


Lisa P. Weeth, DVM, MRCVS, DACVN


Magic Beans? The Wonderful World of Dietary Supplements, Part 2 of 2

If you walk into any pet supply or grocery store you will find an aisle (maybe more) filled with products promising to make your dog or cat smarter, faster, leaner, prettier, more energetic, better smelling, etc. The list of advertised benefits of any given supplement or nutraceutical goes on and on.


As you read in Part 1 of this series the supplement industry is heavy on business, but can be light on science and regulation. That doesn’t mean that there isn’t a place for supplements on your kitchen or clinic shelves. Today’s commercial pet foods (even those at the economy price point) provide all of the known essential nutrients your dog or cat needs without anything being added, but there are a few condition where adequate may not the same as optimal.

I’ve put together a list of what I consider to be my Top 5 Dietary Supplements for health and wellness. Not all of them (or maybe any of them) will be right for your dog or cats, but they are worth getting to know a little better.

So without further ado…

Dr. Weeth’s Top 5 Dietary Supplements


If only we all had a coat that glistened in the sun…


1. Essential Fatty Acids (EFAs): A balance of linoleic acid (LA; an 18-carbon length essential omega-6 fatty acid) and alpha-linolenic acid (ALA; an 18-carbon length essential omega-3 fatty acid) is necessary in dogs to maintain the normal water barrier function of skin and to maintain the suppleness of the hair coat.

Dogs that aren’t getting enough of one or both EFAs can have dull, dry, hair coats, with skin flakes (dandruff) and excessive shedding. These are the dogs that seem to shed a whole other dog when you brush them out. Yes, shed happens, but it happens more robustly when your dog isn’t getting the right amounts or ratio of EFAs in the diet.

The specific amounts required by an individual animal will depend on the overall balance of fats and fatty acids in the diet as well as breed differences in coat texture and length, which means that even diets marketed as “complete and balanced” may miss the EFA mark for optimal skin and coat health in a given individual. Supplementing higher levels of ALA has been shown to help improve skin and coat quality in otherwise healthy dogs and may help decrease itchiness in those with allergic or atopic dermatitis.

  • Who would benefit? Otherwise healthy dogs with dry, flaky skin or with excess shedding; dogs with dermatitis caused by an allergic reaction (e., abnormal and excessive immune reactions to food, flea, environmental triggers) or atopy (i.e., abnormal and excessive immune reactions to an unknown trigger).
  • How to get it? Many of the powders, pills, and chew that are marketed to “complete” a commercial diet for dogs and cats are simply dressed up ground flaxseed, a source of the essential omega-3 fatty acid ALA. Corn on the other hand (an oft demonized, but utterly delicious cereal crop) is high in the essential omega-6 fatty acid LA. Adding ground flaxseed doesn’t have magic fairy dust-like properties, it simply balances the LA:ALA ratio in most commercial diets, which supports a healthier skin barrier and allows the shedding fur to slip past each other instead of “felting” and coming out in clumps.
  • Use with caution in dogs with a history of pancreatitis or other fat intolerances (hyperlipidemias or diarrhea). Care should also be taken in animals with suspected or document allergies as many of these flaxseed-based multivitamin/multimineral/fatty acid supplements contain additional proteins that could trigger or exacerbate an allergic response.



SAMe and the liver, a happy pair.

2. S-Adenosyl-Methionine (SAMe): SAMe is normally made in the liver of all animals. It serves as a precursor to taurine (an amino acid) and glutathione (an antioxidant); supports liver cell regeneration; and helps the liver metabolize a number of different compounds and drugs.  All features that make SAMe an attractive supplement for animals with liver disease when SAMe production is decreased.

Scientific evidence for SAMe’s use in dogs and cats with primary liver disease is largely anecdotal or based on in vitro (cell culture) tests, though SAMe supplementation has been shown to protect the liver from toxic side effects of CCNU (a type of chemotherapy drug) in dogs undergoing cancer treatment and may improve behavioral traits in dogs experiencing age-related declines in cognitive function (old dogs that start to act like old dogs). Similar cancer treatment and geriatric studies have not been published in cats, but SAMe supplementation has been shown to limit the effects of acetaminophen (the active ingredient in the pain reliever Tylenol) toxicity.


  • Who would benefit? Dogs with congenital or acquired liver disease; dogs undergoing cancer treatment; older dogs in general; and cats exposed to acetaminophen. Cat with liver disease and geriatric cats may benefit form SAMe supplementation as well, but without published evidence on its use, SAMe for cats falls into the category of “not harmful, possibly helpful” so worth a try if you can give pills to your cat.
  • How to get it? There are a number of commercial SAMe supplements sold for both veterinary and human use and either type may work for your dog or cat. When selecting supplements (marketed for pets or people) it is important to know that SAMe is prone to degradation during manufacturing and storage so capsules and enteric coated pills are better than chewable wafers.
  • Another key consideration when supplementing SAMe is that it undergoes a significant first-pass metabolism with approximately 50% of the ingested SAMe being metabolized by the liver before it can be used as SAMe itself. Additionally, the presence of food in the stomach can decrease absorption of SAMe even further, meaning that SAMe supplements should be given on an empty stomach at least 1 hour before a meal to have maximal absorption.


everyone poops

Everybody poops, but maybe probiotics could help them poop better.

3. Probiotics: Probiotics are beneficial bacteria, such as Lactobacillus, Bifidobacter, and Enterococcus, that may help support normal colon cell health and normal gut-associated and whole-body immunity. They do this by inhibit growth of more pathogenic intestinal bacteria strains; enhancing immune function at the level of the gut; and exerting a trophic (growth-like) effect on the intestinal cells themselves.

In otherwise healthy animals, probiotic supplementation may not give your dog or cat perfect poops or make them extract more nutrients from their diet (both marketing claims I’ve seen), but it may help swing the balanced of colonic bacteria away from potentially pathogenic strains such as Clostridia perfringens.

Clostridia overgrowth is associated with acute diarrhea in dogs and cats so theoretically reducing their numbers may have longer-term health benefits. In dogs and cats with acute diarrhea or in dogs with chronic intestinal diseases probiotic supplementation may actually help normalize the colonic bacterial environment (what is called the gut microbiome) and improve clinical signs of soft stool and diarrhea more rapidly than when medical treatments (antibiotics and immune-modifying medications) are given alone. The beneficial effects of probiotics may also extend beyond the gut itself. For example, probiotic supplementation may improve clinical signs of atopic dermatitis in dogs.


  • Who would benefit? Dogs and cats experiences chronic or acute diarrhea; dogs with atopic or allergic dermatitis.
  • How to get it? Probiotics marketed for pets or people can be used to provide a source of beneficial intestinal bacteria, though certain veterinarian strains may be more effective in cats and dogs than the human counterparts. There is also variability between product strains and in manufacturing and stabilization processes, so I recommend using a probiotic supplement from a reputable manufacturer.
  • Unfortunately, the amounts of probiotic bacteria found in fermented foods like yogurts and kefirs are relatively low compared to what is found in a supplements capsule or wafer so you are better off with giving a good quality probiotic supplement rather than relying on a daily yogurt treat. It is also important to know that even the best probiotic supplement won’t be enough to correct diarrhea by itself. If your dog or cat is having diarrhea that lasts for more than 24 hours you should seek veterinary care and treatment sooner rather than later. Your pet and your floors will thank you.


dog with salmon

This old dog has the right idea.

4. Fish Oils: Fatty fishes like salmon, cod, and menhaden are high in the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

DHA is incorporated into the fatty insulation of nervous tissue and is essential for normal eye and brain development of puppies. EPA on the other hand isn’t essential in the diet (meaning your dog or cat will survive if fish oils are left out), but in adult animals increased intake of EPA can help decrease production of pro-inflammatory mediators and help manage arthritis pain, atopy, kidney disease, heart disease,  lymphoma treatment, and may help support brain health in older dogs and cats .

  • Who would benefit? Older dogs and cats, especially those with chronic diseases, such as heart or kidney disease, or that are being managed for inflammatory conditions, such as skin or intestinal allergies.
  • How to get it? Fish oils can be given as either a liquid or capsule, but manufacturer quality control is essential. Supplements should be checked to be free of environmental contaminants (e.g. mercury or PCBs) or excess levels of vitamins A and D, which can be toxic to dogs and cats. Product quality and testing should be done by every fish oil manufacturer, so it is worth spending a little time looking into manufacturers before spending your money.
  • Caution should be used when adding fish oil to cat diets as platelet abnormalities and bleeding disorders have been reported in cats receiving high dosages of EPA. Additionally, increased intake of EPA and DHA will increase the requirement for vitamin E in the diet. Without enough vitamin E cats fed high fish oil diet are at risk of developing painful inflammation in their fatty tissues (called pansteatitis).
  • Added Note: Fish oil should not actually smell “fishy”; this odor change occurs when the fatty acids in fish oil begin to break down from improper handling or storage. You should also be forewarned, as the long-chain fatty acids from fish oil are incorporated into every cell in your pet’s body they will eventually be incorporated into skin oils, which will begin to oxidize giving your dog or cat a distinct fishmonger aroma.




Old dogs have old joints. Could supplements keep those joints young?

5. Glucosamine/Chondroitin Sulfate: Synovial joints (ones that allow movement between bones) are composed of cartilage matrix (the proteoglycans hyaluronic acid and glucosaminoglycans -or GAGs for short), collagen, and water. Inflammation in the joint (arthritis = arthr– joint + –itis inflammation) can result in damage to the joint tissues and potential loss of chondrocytes (the cells that line the joint and product the matrix proteins).


Oral glucosamine and chondroitin sulfate supplements have been theorized (and marketed) to provide precursors to matrix GAGs and help improve mobility in animals with arthritis, but results of clinical trials on glucosamine and chondroitin sulfate supplements have been mostly disappointing. Lack of efficacy in controlled clinical trials could mean that these supplement just don’t work, or maybe failure of a response is related to the severity of existing damage to the joint and degree of chondrocytes loss rather than complete futility of glucosamine and chondroitin sulfate supplements in all animals.

I wonder if we have been looking at these supplements the wrong way. Maybe oral glucosamine and chondroitin sulfate supplements are more chondroprotective rather than chondroreplacive (I think I just made up a new word), and should be started before damage (or at least significant damage) has occurred. This would be a very difficult to prove or disprove in clinical trials, but since glucosamine and chondroitin sulfate supplements appear to be relatively safe for both dogs and cats, they  fall into the “possible helpful, but not harmful” category.

  • Who would benefit? Canine athletes, feline athletes (if such a creature existed), and possibly every middle age to geriatric dog or cat.
  • How to get it? Veterinary and human glucosamine and chondroitin sulfate supplements are available. Veterinary supplements are often flavored to increased acceptance by dogs and cats, but a number of human supplements products may contain comparable amounts of glucosamine and chondroitin sulfate.
  • Caution should be used if you are considering giving a human supplements as some joint health products may include additional nutrients (like high levels of vitamin D) or herbal mixtures that have not been safety tested in dogs and cats. Occasionally  vomiting has been reported in dogs given glucosamine and chondrointin sulfate supplements, but this appears to be caused by stomach irritation rather than any innate harmful effects of the supplement.


The reality of nutrition is that it is not one-size-fits-all. Needs will vary based on breed, life stage, health status, and activity level. Even though commercial pet foods from good quality manufacturers (check out this link to help define “good quality manufacturers”) will provide all of these essential nutrients at levels adequate for survival, what is adequate for day-to-day living in one animal may not be the same as what optimizes health and wellness in another. This is where supplements come in.

And one last note: Supplements should never replace proven medical treatments for your dog or cat, but when added to a balanced diet, regular exercise, and preventative veterinary care, could help keep them feeling good for years to come.


Happy Feeding!

Lisa P. Weeth, DVM, MRCVS, DACVN


The Wonderful World of Dietary Supplements, Part 1 of 2

Food fads and “miracle” supplements.  Even our Victorian-era ancestors fell prey to these marketing gimmicks (click here for some fun adverts). Back then it was whole grain cereals and cure-all liniments that would fix what ails you; now it is gluten-free/paleo/vegan diets and coconut oil that have the marketing companies and self-proclaimed nutrition gurus in a frenzy to separate you from your hard-earned money. They are not just targeting you, but your furry, four-legged companions, too.

But is there a place where nutrition science and marketing converge to improve health and wellness? The answer is a resounding … maybe. But before we get into specifics, let’s take a look at the industry as a whole.

Belgian agility

Faster, stronger, better. That is the marketing woo of many supplement companies.

A Background on Dietary Supplements

The supplement industry is Big Business and growing each year.  Thanks to the 1994 Dietary Supplement Health Education Act (DSHEA for short) supplement companies have almost as much pre-marketing oversight as they did in 1894, but at least now the FDA can step in (after the fact) if there is a problem.  For human supplements that is. Veterinary supplements are not covered by DSHEA and are still considered “animal feed.” As the FDA states “the ultimate responsibility for the production of safe and effective animal feed products lies with the manufacturers and distributors of the products” (to read the original document look here). Not a great comfort knowing that the companies that stand to profit from selling a given product are the same ones responsible for regulating safety and efficacy.

It can be hard, even for me, to keep all the brands and product straight and I still come across new ones all the time. To help me evaluate these new supplements as I see them, I’ve come up with a list of product and company questions that I ask each time.


Just a few things before we get started…

General Questions on Dietary Supplements

  1. How much of each nutrient is in the supplement? I want actual nutrient or compound concentrations in milligrams (mg) or grams (g) here. If I call the supplement provider and ask for specific concentrations of vitamins and minerals and they send me an ingredient list, they may not understand the role of nutrients in health and disease. I’ve even talked to “scientific advisers” who couldn’t understand why I would need to know how much calcium, zinc, iodine, etc., is in the product the company recommends as a supplement to balance home-prepared diets. (The short answer is that I need to know how much to add to meet the dogs daily requirement.) Telling me the ingredients are “all-natural” doesn’t mean anything if it’s naturally deficient in zinc and iron, or has naturally toxic levels of vitamin D.
  2. Is it being used to fill a deficiency or manage a condition? Today’s commercial pet foods are intended to provide all essential nutrients your dog or cat needs, but individual animals may have higher requirements for things like essential fatty acids or fiber than what the diet alone provides. Certain non-essential nutrients, such as long-chain omega-3 fatty acids, may also help animals with chronic medical conditions. Know what you are using and why.
  3. Who makes the supplement? Is it a company that makes both human and veterinary supplements? Or only pet products? Maybe this is a faulty assumption, but I can’t imagine that companies manufacturing both human and pet products use two different sets of quality and safety standards. Not to imply that vet-only products are necessarily lower quality. Many are made by private label human supplement companies, or are members of the National Animal Supplement Council (NASC), or are both. The point is, I would encourage veterinarians and caregivers to know who manufacturers and oversees the supplements they use.
  4. What else is in the supplement? Supplement (for pets or people) do not require pre-market approval, so it is important for veterinarians and caregivers to be in the habit of scanning the ingredient list to look for potentially problematic or harmful ingredients.

what plants crave

What I think about when I hear people spout off about the unproven “benefits” of certain supplements. Repeating marketing catchphrases is not a valid scientific argument.

My quick tips on products to avoid:

  • NO garlic for dogs or cats. Garlic contains a compound that damages red blood cells causing the cells to rupture and animal to develop anemia. Even if you don’t believe that garlic is a problem for dogs (though the science show us that it is) everyone should know that garlic is toxic to cats. If you see a supplement marketed for dogs and cats that included garlic (which I have), put it back on the shelf and walk away. If they don’t know what’s toxic to their intended users, what else don’t they know?
  • Please don’t feed coconut oil to your cats. Coconut oil seems to be the pet health food trend de jour. Claims I’ve read on coconut oil marketing materials: cures skin disease and allergies, eliminates bad breath, elevates metabolism (whatever that means), prevents diabetes, allows your dog to telepathically communicate with you (ok, I made that last one up). It is marketed as a panacea and miracle cure for pets. Coconut oil may have some helpful uses in dogs, though it is not what the coconut oil panderers want you to believe (more on coconut oil for dogs in my next post), but I would not recommend it for cats. They really don’t seem to like it. Yes, I know that there are weird cats out there that love bananas and strawberry jam (I have one), but feeding coconut oil to cats can cause food refusal and an aversion to the diet. I would be highly skeptical of any person or product company that told you to do so.

Dietary supplements can play a valuable role in health and wellness for your pets or your patients, but just like any other treatment though, we need to make sure that what we are doing is safe and effective.

cate and annabelle

We want to keep these two happy, or at least mostly happy. Annabelle doesn’t look like she likes hugs very much.

Happy Feeding!

Lisa P. Weeth, DVM, DACVN

For more on specific supplements to consider for you patients or pets check out my next post!

I Love Cats!…and Cat Nutrition


I would have to say that my home doesn’t feel complete without one (or more) feline companions. Don’t get me wrong, I love dogs, too (and rats, and horses, and bunnies, and birds, and reptiles, and yes, tarantulas … pretty much any animal), but there is something about cats that has resonated with me since my childhood. Cats can be cool and aloof, snuggly and sweet, playful and silly. And let’s face it, usually lower maintenance than any of the animals I mentioned earlier, which is an attractive feature in a busy household.  And I’m not alone in my love of cats. Cats are the most common companion animal in the United States with 30% of households living with 74+ million cats. A recent study even showed that just watching cat videos can make you happier and more productive at work.


With so many cats in the US (and the world) we humans must be doing something right when it comes to the care and feeding of our feline friends, but over the last 10-15 years there has been a push to feed cats what is considered the “natural” diet of the domestic feline and the what and how to feed has become a confusing mess for concerned cat lovers.  What is the natural diet of the domestic cat?  Cats are obligate carnivores, which mean that they are adapted to a diet that consists of eating other animals, and many people (veterinarians and non-veterinarians alike) advocate feeding a high protein, high fat, and preferably wet food diet to every cat. While this may be ok for a young healthy individual, animals with specific medical conditions such as liver or kidney disease can become very ill when fed a high protein diet. Calorie for calorie, wet food is also more expensive than dry kibble. What about families that cannot afford to feed a wet diet exclusively? Like everything in the nutrition world, the purrfect cat diet (sorry I couldn’t resist) depends on the individual cat and the individual household.


A tale of two cat diets…



What is the Ancestral Diet of the Cat?

Archeological and genetic evidence indicates that cats began living with humans approximately 12,000 years ago probably after the shift in food production from a hunter-gatherer life-style to that of farmed (and stored) agricultural products. Chances are the small rodents they found among the stored grains came complete with stomachs full of grain bits, too.  I would argue that barley and wheat (a couple of the earliest domesticated cereal crops) are natural parts of the cat’s diet, albeit in more limited quantities than what can be found in some dry cat foods. Then 50-60 years ago a dietary shift once again occurred when advances in feline nutrition and food technology led to the development of nutritionally complete commercial dry and canned cat foods. Any amount of (hopefully) fresh meat can be put into a can, but extruder (the machine that makes the kibble) technology set the minimum and maximum amounts of protein and carbohydrate that could be used in dry pet food production. Too much wet meat in the extruder and the dough wouldn’t blend or cook properly; Too little carbohydrate and the kibble wouldn’t stick together.  Newer extruders have been developed over the last 10+ years that allow companies to make dry foods with much higher animal protein contents, but to this day many of the “original recipe” dry cat foods on the market will have a lower protein, higher carbohydrates content relative to wet diets because of extruder requirements rather than feline requirements.

Coinciding with this more recent diet shift has been a change in the overall care and husbandry of domestic cats. Cats as a population are spending more time in the safety of our homes with a ready food supply instead of outside defending territory and hunting for prey (such as mice, lizards, small birds, and insects). Indoor-only cats have a decreased risk of exposure to pathogens such as feline panleukopenia and a decreased risk of trauma from vehicles or larger predators, but there is concern in the veterinary profession and among cat owners that this change in diet from a high protein, high moisture, low carbohydrate wild-type diet to a moderate protein, moderate carbohydrate, low moisture diet has contributed to a number of current-day feline diseases, such as obesity, lower urinary tract disease, and diabetes mellitus.

cat mouse

Just a quick game of cat and mouse.


The Influence of Feline Feeding Behavior

Cats, as any cat caregiver knows, are creatures of dietary habit.  Research has shown that kitten food preferences  are influence by maternal food exposure as well as aspects of the diet itself, such as texture, mouth feel, and aroma. As a cat ages it can demonstrate more food aversions and can resist diet change becoming neophobic (i.e., fearful of new things) even when a diet change is in their best interest. This may be an adaptive response to minimizing risk of food toxicity in the wild, but will frustrate veterinarians and caregivers trying to manage certain medical condition where the feeding of a particular style of food may be recommended (e.g., higher moisture canned foods for cats with a history of sterile cystitis). In addition to specific diet characteristics, environment can influence feeding behavior with many cats experiencing a decrease in food intake during stressful times. Yes, there are some cats that relish the new novel diet, but I would argue that this may be due to unintended training by the caregivers (who doesn’t love a good sale on cat food?) rather than the cat beig inherently adventurous. In an otherwise healthy young cat varying the diet textures and flavors may be the most important feeding strategy a caregiver can make to keep their food preferences flexible. I am not trying to help you feed a kitten, I am trying to help you feed for the entire lifespan of the cat.


FYI- These are not on the recommend food list for cats.

Pet Food Manufacturing: Effects on Health and Wellness

Current complete and balanced commercial cat foods are designed to provide adequate levels of all essential amino acids, fatty acids, vitamins, and minerals without the need for supplementation irrespective of diet type. The one exception would be that dry diets provide very little water (8-10% of the volume of a dry food vs. 70-85% of the volume of a wet food) and cats will not simply drink more water to make up the deficit. [This lack of water intake can result in urinary crystals or bladder inflammation in some, but not all, cats.]  Even with the perfect diet design, heat and pressure processing (i.e., cooking) that occur during pert food manufacturing can destroy a number of essential nutrients, which will need to be added back in or accounted for by the manufacturer.  Even without cooking, fats and fat-soluble vitamins will oxidize and become rancid with exposure to air and minerals will antagonize one another and prevent each other’s absorption. These are well known complications of cooking and food processing that can adversely affect feline health and are hopefully well-known by the pet food manufacturer. But even with all of the nutrition and food science knowledge available to pet food manufacturers mistakes can happen that result in serious harm to companion cats such as when 100% of the added thiamine was degraded during manufacturing. These diets looks perfectly balanced on paper, but deficiencies would have been seen during an Association of American Feed Control Officials (AAFCO) feeding trial or if these manufacturers had tested key nutrients after production of each batch.


Feeding for fit, not fad.

“Wild-Type” vs. Dry vs. Canned Diets

A typical well-fed adult house mouse (https://archive.org/details/CAT11124570)  is relatively high in moisture (67% moisture as fed), with a crude protein content of 55% on a dry matter (DM) basis, a crude fat level of 24% DM basis, and an estimated carbohydrate content of 8% DM basis. Compare this to a typical over-the-counter adult cat dry food with a lower moisture content (10% moisture as fed), a crude protein level of 34-45% DM basis, crude fat level of 13-20% DM basis, and a carbohydrate content that can range from 8-30% DM basis depending on manufacture and product formulation. The typical over-the-counter adult cat wet diet is a little bit closer, but still not exactly right: Wet diets have a moisture content of 70-85% as fed depending on style, a crude protein content between 40-70% DM basis, a crude fat content of 22-36% DM basis content, and a carbohydrate content that can range from 0-15% DM basis depending on manufacture and product formulation. Just from a simple comparison of a representative “wild-type” prey species, a “typical” dry cat and a “typical” canned cat food, canned diet profile appear to be a closer match the nutrient distribution of a prototypical feline diet. Carbohydrates, both starches and structural carbohydrates (i.e., fiber), are not considered essential nutrients for cats but are essential ingredients for the production of dry cat foods and allow for the formation of a kibble as the ingredients go through the cooking, extrusion, and drying process. Cats are able to metabolize a range of dietary carbohydrate contents whether found in a can or kibble form, and carbohydrates provide a source of non-protein calories that are useful when managing certain medical condition, like kidney disease, when a protein restricted diet is required.

Domestic cats in the wild eat multiple small meals a day (a baby bird here, a cricket there…), and many caregivers will leave dry food out all day to allow their cat or cats to eat at will. While this is a more “natural” feeding pattern for cats, the diets they are grazing on tend to be very palatable and very energy dense (some are 500+ Calories per cup!) and a free-grazing cat can quickly consume more than its daily energy requirement if excess food is available. Some cats are very good at regulating intake, but there is a fat cat in every multi-cat household who ruins it for everyone. Allowing some cats free access to dry food can lead to obesity and its associated complications of diabetes, urinary tract disease, breathing problems, skin disease, and joint disease. Most cats can be trained to eat two to three meals each day with occasional small treats offered in between meals, if extra nibbles are desired, and wet food is especially conducive to portion control.

Porkchop and corn

Shh, don’t tell her she’s not supposed to like corn.

The Bottom Line…

As with most aspects of diet selection, there is not one perfect approach to feeding cats. Individual animal and caregiver characteristics will influence diet selection and owners should be encouraged to offer a variety of taste and textures early in life to help ensure acceptance of a range of food types as the cat matures. Canned adult maintenance cat foods may be more similar in moisture, crude protein, crude fat and estimated carbohydrate content compared to whole prey (though this is not universally true of all caned cat foods). But, neither a canned cat food nor a dry kibble exactly matches the “wild-type” diet of a domestic cat. Providing a complete and balanced diet, irrespective of diet type, is known to promote health, wellness, and longevity and there is no evidence to support the notion that either canned or dry diets are nutritionally superior for the average healthy adult cat. Dry cat foods are more convenient and economical for owners than canned cat foods, whereas higher moisture canned diets may aid in the medical management of numerous feline maladies. Diet selection should be based on the individual cat and household needs rather than on current diet trends and fads. And don’t forget to keep your cat lean!



Dusty getting his 1-2 servicing of insects each day.


Happy Feeding!

Lisa P. Weeth, DVM, MRCVS, DACVN


Nutrition and Cancer: What We Can and Can’t Do

In case you were wondering what a typical day in the life of a Veterinary Nutrition Specialists is like, my working days are mostly filled by those with chronic diseases: diabetic cats with kidney disease; dogs with food allergies and pancreatitis; maybe a diabetic dog with food allergies, history of pancreatitis, kidney disease, AND a picky appetite just to make it interesting. But on one particular day a few years back my first appointment of the morning was a little different. The reason for the visit as listed in the medical chart was “questions about preventing cancer” and my soon-to-be patient was a 4 month old Golden Retriever puppy full of happy, healthy, fluffy, puppy cuteness.


Not an actual picture of my patient, but just as cute.

After introducing myself to the puppy and his people I quickly learned what brought them in seeking cancer prevention advice. Turned out that this particular puppy was the fourth in a series of GoldenS cared for by the owners over the previous 20+ years. The first died at 10 years of age from hemangiosarcoma (an aggressive cancer of blood vessels that usually starts in the spleen and quickly spreads in the body), the second at age 6 from osteosarcoma (an aggressive cancer of the bone that usually starts in one bone and can spread throughout the body), and the third died at 2 years of age from lymphoma (an aggressive cancer of one of the white blood cell families, that can go and do whatever it wants). Their most recent loss was less a year before our appointment, so needless to say, this couple was very concerned about losing this new puppy too soon. They wanted to know if there was anything they could do diet and supplement-wise to prevent cancer from striking another four-legged family member.



Another gratuitous puppy picture.

If any of my readers were wondering that same thing, the short answer was no. There are no proven dietary changes or nutritional supplements that have been definitively shown to prevent cancer in dogs and cats. Cancer is a leading cause of death in dogs and cats with genetics, viruses, environmental toxins, age, and neuter status all having a direct or indirect role in the development of certain types of cancer.

So what do dog and cat caregivers need to know about cancer and possible nutritional prevention/treatments?

#1: What causes cancer?

Cancer results from damage to DNA (the genetic code of every cell) that 1) allows that cell to replicate itself unchecked, 2) to avoid normal housekeeping systems that would otherwise destroy an abnormal cell, 3) to induce new blood vessels growth to supply the cancerous cells with nutrients, and 4) to spread either locally or distantly (or both).

Cancer incidences are higher in certain pure-bred dogs than in mixes; viruses such as feline leukemia virus (FeLV) and transmissible venereal tumors (TVT) can induce cancer development and are acquired by close contact with infected animals; unneutered male dogs can develop testicular tumors just as unneutered females can develop uterine cancer (the risk of these two tumor types is virtually eliminated with neutering); cats and dogs living in households with heavy smokers have an increased risk of oral and nasal cancers due to environmental tobacco exposure. Additionally dogs and cats today are living longer thanks to vaccines, complete and balanced commercial diets, and advances in medical prevention/treatment of other diseases. Essentially, by preventing other potentially fatal diseases we have opened up the playing field for cancer in older aged dogs and cats.

Breed predispositions play an especially important role in cancer occurrence in Golden Retrievers. Goldens are beautiful, smart, dedicated family dogs, steadfast companions, but they are also a breed that has among the highest risk for cancer development at any age. This is one of the primary reasons for the development of Golden Retriever Lifetime Study. This study enrolled 3000 young Goldens and will track the genetics, environment and diet of each individual dog to help identify risk factor and possible prevention strategies for cancer as well as other chronic disease. This is a huge undertaking not only by the researchers, but the family committing their beloved canines and their own time to this study. At the time of my puppy appointment, the Golden Retriever Lifetime Study had not yet been launched and it will be at least a decade, if not longer, before we have any inkling of results.

What can dog and cat caregivers do about these risks? If you are adopting a purebred dog or cat, learn about the breed and what conditions can typically affect that breed. Do your research on any potential breeders as well. Find out what steps (if any) they are taking to screen their breeding pairs for known and potential health problems. Is the breeder tracking disease incidences (including cancer occurrence) in their lines? Once that cat or kitten is in your care, vaccinate for FeLV, if they are considered to be at-risk for this disease. Since FeLV is a “social” virus that required direct contact with an infected cat, indoor only cats in a FeLV-free household don’t typically need annual boosters. But talk to your veterinarian about your individual cat’s risk before stopping any vaccine regime. Canine TVT is a sexually transmitted disease, and both testicular and uterine tumors require intact reproductive tracts so the best way to prevent all of these is by neutering your dog. And if you are a smoker who hasn’t/can’t/doesn’t want to end their habit, at least smoke outside away from your dog or cat.


Old age happens, but it’s better than the alternative.


#2: What about specific foods and cancer risk?

If you are reading my posts, you are interested in canine and feline nutrition and have likely read other websites that claim that “kibble causes cancer” or that there are “cancer causing preservatives in pet food”, but scientific evidence for these claims is very much lacking. These claims are also almost always made by either a distraught pet owner looking for someone to blame for unexpected cancer diagnosis or by a person or business trying to market their own special line of “miracle cure-alls.” Our old Labrador, Maggie, lived 14 ½ years eating primarily dry dog food (with the occasional pizza or bread roll stolen from the counter when we weren’t looking), and ultimately died from a stroke-like event that hit her one morning. My 18-year-old cat Oliver is asleep next to me right now, has eaten dry commercial food his whole life and, other than his arthritis, is the picture of geriatric health; while our 3-year-old cat Cosette had eaten a variety of canned and dry foods over her short life, loved eating cat grass (that I grew myself) every day, and just died from transitional cell carcinoma in her left kidney (a rare cancer in cats, let alone in one so young). I don’t blame Cosette’s once-a-day cat grass habit for her developing cancer nor do I attribute Oliver’s longevity and health to dry food; cancer happens even to good cats and dogs.

But what does the vet literature say? There are some published veterinary studies that have tried to find an association between specific food intakes and cancer risk. One study looked at feline oral squamous cell carcinoma and another looked at thyroid adenomas in cats, but both of these studies relied on owners to report frequency and types of foods given over years to decades prior to the cancer diagnosis. Another study in dogs tried to draw a connection between intake of fresh fruits and vegetables with lowered risk of transitional cell carcinoma in Scottish Terriers. Again, these researches relied on owners to recall types and amount of fresh produce fed over the previous years. Most people can’t recall how much fruit and veg they fed themselves over the last week, let along how much they fed their dogs. I’ve worked with people who can’t even remember the name of the food they use (“it’s the purple bag with black writing”) or live in household with multiple feeders (intentional and unintentional). Recall bias is essentially the over- or under-reporting of foods and lifestyle habits that a responder thinks may be associated with a particular disease state. Recall bias is a significant enough problem in human health studies that nutritional epidemiologists have almost completely abandoned this method of data collection, yet for some reason veterinary researchers still rely on it. Food recall is always faulty in my clients, and they are highly motivated to remember their dog or cats food intake. To date, any veterinary study using only caregiver food recall to draw conclusions about diet and cancer risk in dogs and cats should be taken with a heavy dose of skepticism.

What do cat and dog owners need to know about commercial diets and cancer risk: Improvements in disease prevention, nutritional needs, medical care, and diagnostics mean that today’s cats and dogs are living to ages when accumulated DNA damage can result in cancer. Feed a complete and balanced diet that meets your individual animal and family’s lifestyle needs. If you want to feed a varied diet or a portion of fresh foods on a regular basis, that is no problem, as long as the overall diet still meets your dog or cats nutritional needs, they tolerate it well, and the foods selected are not harmful (no toxic foods like garlic or grapes, and avoid feeding foods that contain Salmonella or Campylobacter).

vegetarian dog

The wild ‘carnivore’ back from the hunt.

 #3: What about the role of obesity in cancer development?

This may be the one area of nutrition and health that could impact disease prevalence. In people, obesity has been shown to increase risk of specific cancers, such as uterine, liver, and post-menopausal breast cancer. These same associations haven’t been seen in dogs or cats, but calorie restriction has been shown to decrease cancer risk in rodent and primate models. The only published prospective (meaning they started with healthy dogs and followed them forward in time) study in dogs to date that looked at lifetime intakes and disease prevalence showed an equal number of cancer occurrences in lean and overweight dogs, but the small sample size (only 48 dogs in total) make this comparison almost meaningless. The results of the Golden Retriever Lifetime Study may give us more insight into this question.


What do cat and dog owners need to know about obesity and cancer risk: Lack of scientific data doesn’t mean that there is not an association between obesity and cancer development in companion dogs and cats, it just means that we don’t have a study that could answer this question. Even in the absence of a clear link between obesity and cancer, excess weight is a proven risk factor for other problems in dogs, and cats including joint disease, diabetes, skin disease, breathing difficulties, and at least in dogs has been shown to decrease longevity.



There may be less to love, but you can love them longer.

#4: What about the role of carbohydrates and cancer?

A quick Google search on “carbohydrates and cancer” will give pages of websites claiming to prevent or cure cancer by avoiding carbohydrates, and especially carbohydrates that include GMOs and gluten (the “evil” ingredients du jour). And there is big money in making these kinds of diet claims. Just look at the recent Belle Gibson story. Her fake cancer and food cure story garnered her hundreds of thousands of followers (and dollars), spawned a book, an app, and stories in international magazines, until she was recently exposed as a fraud and a thief.

There is one veterinary study that the anti-carb people like to point to and shout, “See, carbohydrate influence cancer!” It was published in 2000 and looked at response to cancer treatment in dogs with lymphoma fed a low carbohydrate (18% of the calories) diet supplemented with fish oil and arginine. Low carb advocates (including one of the lead authors) have cherry-picked the results of this study to make claims like “dogs with cancer should be fed a low carbohydrate diet” and “carbohydrates feed cancer” (emphasis is mine), yet when you read the entirety of the paper you learn that the control diet (the non-supplemented diet used as a comparison for the supplemented diet) had the exact same carbohydrate content as the study diet, just no fish oil and extra arginine. And the low carb control diet had absolutely no influence on cancer progression relative to expected outcomes. Again, feeding a low carbohydrate diet alone made no difference in disease free interval or survival time in these dogs with lymphoma. Yes, cancer cells utilize blood sugar (glucose) more rapidly than the surrounding normal cells, but this happens whether the individual consumes carbohydrates directly in their diet or if the blood glucose is produced from glycogen (a type of carbohydrate stored in the muscle and liver) or from gluconeogenesis (production of glucose in the liver) from metabolism of fatty acids and amino acids (building blocks of protein). The body of an adult, non-reproducing, non-lactating animal is very good at maintaining blood sugar levels, even when fed a carb-free diet. Additionally, there is not a single veterinary study that has demonstrated that dogs or cats fed low to no carbohydrate diets have less cancer incidence than dog or cats fed moderate to high carbohydrate diets. Not that I am advocating that dogs and cats should be fed lots of starches and simple sugars, I just don’t want people to wave the cancer prevention/treatment flag when touting the “benefit” of a carbohydrate-free diet.


What do cat and dog owners need to know about carbohydrates and cancer risk: At this time there is no evidence that a diet with a low (less than 20% of the calories), moderate (20-40% of the calories), or high (greater than 40% of the calories) carbohydrate content has any bearing on cancer development in dogs and cats. There may be other reasons to feed a reduced carbohydrate diet, like management of feline diabetes, and animals with insulin secreting tumors (insulinomas) will often benefit from a reduction in overall carb intake, but like for all conditions the specific diet selected for your dog or cat should encompass their whole health needs.


Porkchop and corn

Psst, no one told her she wasn’t supposed to like corn.


#5: What about antioxidants for cancer protection?


The most common supplements marketed for “cancer prevention” or “cancer treatment” include combinations of antioxidant compounds, such as vitamin C, vitamin E, carotenoids, and selenium. On the surface this may seems to make sense. Antioxidants exist within each cell to balance and prevent the accumulation of reactive oxygen species (ROS) that are formed during normal cellular metabolism. These ROS can have damaging effects on nearby DNA, effects that could potentially end up in cancer development. The balance between formation of ROS and antioxidant capacity of the cell is dependant on dietary intake of antioxidants compounds, as well as the demand on the antioxidant systems through exposure to oxidative damage. So supplementing antioxidants seems like a smart thing, right? Maybe not. In people increased intake of antioxidants may influence cancer development, but not in the way we want. Prospective studies in people have shown that supplementing beta-carotene and vitamin A may increase the risk of lung cancer in smokers; high dosage vitamin E may increase prostate cancer risk; and women (but not men) taking high dosages of vitamins C and E, selenium and zinc, may actually be at an increased risk of skin cancers.  And there are a number of other studies looking at different cancer that have shown no effect (good or bad) of antioxidant supplementation. It is important to note that these studies in people were based on longer term (5-15 year studies) using tens of thousands of individuals. Veterinary medicine hasn’t done anything like this, until the Golden Retriever Lifetime Study and even that would be considered small by human study stanards.  There are no published studies evaluating specific antioxidant supplementation and cancer prevention in dogs and cats, though increased antioxidant intake in older dogs may help protect cognitive ability.

What do cat and dog owners need to know about antioxidants and cancer risk: There is no evidence that increased intake of antioxidants will prevent cancer in dogs and cats, and if anything, the studies in people have demonstrated that megadoses (10-100X normal dietary requirements) of certain antioxidants may actually increase risk of certain cancers. Antioxidants consumed as part of a healthy, balanced diet are fine, as are naturally occurring antioxidants found in fresh fruits and vegetables (non-toxic ones of course). There may also be some benefit to cognitive function with moderate increases in antioxidant intake in middle age to older dogs and cats.


food scale

It is all about finding the right balance (and avoiding known risks).

The bottom line…

There are no proven dietary strategies or techniques to prevent cancer development in dogs and cats. Defects in tumor suppressor genes, exposure to environmental toxins, obesity, and chronic inflammation have been proposed as causes of tumor development in people and many of these same mechanisms may occur in dogs and cats. Genetic factors and environmental toxins may not be avoidable or preventable, but avoiding obesity and feeding a complete and balanced (no deficiencies, no excesses) are within every caregiver’s control.




Happy Feeding!

Lisa P. Weeth, DVM, MRCVS, DACVN