I have often discussed the problems with homemade pet diets, which are frequently recommended in books and websites that complain about commercial food or proclaim some magic method for preventing or curing disease. Raw diets, grain free diets, and other fads often involve making pet food at home from recipes from self-proclaimed experts in nutrition, though there are also commercial versions of each fad available not long after it takes hold. Of course, the only real experts in pet nutrition are those board certified by the American College of Veterinary Nutrition. And while there is ample evidence that homemade diets are often nutritionally inadequate, (e.g. 1, 2) most of the scary claims about commercial diets are just myths and misconceptions.
A recent study has reinforced these already well-established points.
Heinze CR, Gomez FC, Freeman LM. Assessment of commercial diets and recipes for home-prepared diets recommended for dogs with cancer. J Am Vet Med Assoc. 2012 Dec 1;241(11):1453-60. doi: 10.2460/javma.241.11.1453.
This study looked at recipes from books and web sites that recommended diets for dogs with cancer, as well as commercial diets marketed for use in canine cancer patients, and evaluated the nutritional adequacy of the diets based on established AAFCO or NRC guidelines. The findings were quite clear, and the recommendations consistent with those veterinary nutritionists have been making for some time.
Published recipes of home-prepared diets for pets with various health conditions are rarely nutritionally adequate. None of the 27 recipes identified and evaluated met NRC RA or AAFCO nutrient profiles for all essential nutrients. In some cases, the recipes contained excessive, potentially toxic amounts of nutrients.
Recipes formulated or provided by veterinarians were not more nutritionally sound than were recipes formulated or provided by nonveterinarians.
Only 2 of 39 (5.1%) commercial diets had passed AAFCO feeding trials (one for adult maintenance and the other for all life stages). The majority (35/39 [89.7%]) of the diets were formulated to meet AAFCO nutrient profiles for all life stages (27 diets) or adult maintenance (8 diets
There is a paucity of experimental data that support specific nutrient profiles or ingredients for dogs with cancer. Dogs with cancer do not have higher or lower requirements for protein, fat, calories, or any other specific nutrients, compared with requirements for healthy dogs. Therefore, it is of concern that none of the recipes for home-prepared diets met NRC RA or AAFCO nutrient profiles for adult maintenance in dogs… All of these inadequate diets have the potential to cause nutritional disease at a time when nutrition should be optimized to provide maximum metabolic support and immune system function and to help decrease adverse effects attributable to cancer treatments.
Commercial diets and recipes of home-prepared diets reflected the current popularity of grain-free diets. No data support health benefits of non-grain sources of carbohydrate over carbohydrates provided by grains; however, many manufacturers still tout the nutritional superiority of grain-free products.
Grain-free diets are often marketed as lower in carbohydrate content, but this is not a consistent finding. Approximately one-third of the recipes of grain-free home-prepared diets and commercial diets did not meet the defined criteria for low-carbohydrate diets.
Low-carbohydrate diets are commonly recommended for dogs with cancer on the basis that many cancer cells use aerobic glycolysis and fermentation of pyruvate to lactate as a main source of energy… it is theorized that feeding a low-carbohydrate diet could effectively starve cancer cells through a decrease in the supply of glucose. However, despite the fact that this theory has been in existence for nearly a century, minimal data have been published to support the tangible benefits of low-carbohydrate diets for any species of animal with cancer. To our knowledge, there are no published data to support the contention that low-carbohydrate diets are of clinical benefit with regard to tumor growth, disease-free interval, or survival time in dogs, and further studies are required before appropriate recommendations can be made.
The number of recommendations for feeding raw meat diets to cancer patients is a concern because contamination with pathological bacteria has been reported for raw meat for human consumption and for commercial raw diets. Cancer patients, even those not receiving chemotherapy, likely have some degree of altered immunoregulation, and many dogs receiving chemotherapy are clinically immunosuppressed, which dramatically increases the risk of illness or even death from contaminated food sources. In humans, the risk of illness attributable to foodborne bacteria in cancer patients is such a concern that patients receiving chemotherapy are commonly advised to eat raw fruits and vegetables only when at home.
It is possible that feeding a diet that does not meet AAFCO recommendations or NRC RAs for various nutrients may not cause overt clinical disease. Although some nutrient deficiencies (eg, thiamine or taurine) can be evident in adult animals after a food deficient in those nutrients is fed for weeks to months, it can be months to years before clinical signs are evident for other nutrient deficiencies (eg, calcium in an adult animal). The status of many nutrients is not easily determined, and the first clinical signs of deficiency may be catastrophic (calcium deficiency resulting in osteopenia and pathological fractures or taurine deficiency resulting in dilated cardiomyopathy).
Currently, the authors are aware of no evidence to suggest that cancer patients have nutrient needs that differ dramatically from maintenance requirements. Many dog owners change to home-prepared diets because of an overall perception that they are healthier than commercial diets, rather than because they provide specific nutrient profiles. Thus, it appears appropriate that home-prepared diets be formulated to meet nutrient guidelines similar to those of commercial products.
Homemade diet recipes are almost always nutritionally inadequate, even if formulated by a veterinarian (unless they are a board-certified nutritionist)
There is no evidence for benefits from current nutritional fads such as raw or grain-free diets, but there is the potential for harm from these diets.
Commercial diets are consistently more appropriate nutritionally than homemade diets.
There is little evidence to support the idea that cancer patients should be fed a different diet from healthy dogs (with the possible exception of extra fatty acid supplementation).
Well OK. I know that there are no studies saying that blueberries prevent cancer in dogs for example, but many dry dog foods contain blueberries now. If blueberries did fight cancer in dogs, would the phytochemicals in the blueberries even survive processing? I have the same question concerning vegetables like spinach that are added to dry dog food. I had heard that antioxidants are sensitive to heat. Origin dog food, the most expensive dry food on the planet, contains all of these herbs like Marygold extract and stuff. Even if studies did show that Marygold extract prevented cancer, would it even be worth it? After extrusion, wouldn’t the antioxidants in the Marygold extract have been deactivated? I really want to know if they make it in dry food and I don’t want people to lie about it to try to promote raw feeding.
You’ve hit on one of the key issues with food-based strategies for preventing or treating disease. The form the food comes in is an important variable, and whether or not it is shown to be useful in one form, it still needs to be tested if given in a different form. In the examples you give, even if these compounds have some health benefits, it is hard to know whether adding them to commercial canned or dry diets changes this. Cooking does modify nutrients and other compounds in foods. In some ways this is beneficial (e.g. making the energy in some carbohydrates more available), and in others it can be detrimental (e.g. the inactivation of some vitamins). Some substances in dry foods are cooked at high temperature,s but others are sprayed onto the kibble afterwards and so not subject to heat inactivation. Antioxidants, for example, both synthetic and plant-derived, are are often added after extrusion to ensure they are functional in preventing spoilage. Whether the ingredients you mention are beneficial at all, or if so still beneficial when added to commercial diets, is impossible to say without appropriate research. I don’t think we can assume they aren’t useful as part of dry diets just because dry diets are extruded, but it is a possible issue that should be studied if and when the basic value of these substances is determined.
I’ve been feeling like a bad dog owner because I haven’t put my dog who has small cell lymphoma on a home-cooked diet permanently, so I’m pleased to have found this site. I’ve got him on the best quality dry food and complimentary wet food I can find – high meat content, human-grade meat, no preservatives etc., etc., and it’s pretty low carb. I add the odd raw egg and left over veggies because he likes them. I don’t buy into the idea that all kibble is inherently evil. He thrives on it, eats like a horse and poos fine. He had initially lost weight when he was first diagnosed, so I rotated a variety of oils – olive, coconut, salmon and ghee as it seemed a non-bulky way of increasing calories and he’s put weight back on nicely.
However, I have wondered about using things like L-glutamine as it reportedly helps dogs to maintain muscle mass and argenine as it supposedly helps with immune responses – what are you thoughts on this? Sorry, more questions but is there something I can be supplementing to boost his immune system – what do you think about adding antioxidants to the diet? Is there an evidence-base for this and, if so, what would one add? I understand that fish oil is beneficial but is it worth keeping up the variety?
Thank you for your time reading this post x
The bottom line is there are no clinical studies on such supplements, only theoretical reasoning and lab studies. That means they might help, they might do nothing, or they might make things worse, and nobody really knows. Whether such a risk is worth taking is up to you, but I usually don’t recommend untested treatments for pets who are doing well with conventional therapy, only as a last resort when nothing else is working.
I have been reading for two days on, cancer diets for dogs.
Since reading your article I am wonder what in your opinion is the best food on the market to feed him.
He has been diagnosed with metisatic cancer from the anal gland. They are saying no surgery or chemo any treatment.
You would not know anything is wrong with him, he eats well, plays well, go weight change, the only reason we took him to the dr he was struggling to poo.
They have him on a stool softener which is helping a lot.
But I can not just sit here and just wait till the day he tells us it’s time like they told me.
Any suggestions would be helpful.
I’m sorry that your friend has this awful disease. I understand the desire to do something to try and delay the point at which he is ill of suffering, but unfortunately it is really unlikley that diet will make a significant difference in the outcome for your dog. While there are lots of theories and some lab studies concerning how nutrients affect cancer generally, there isn’t any reason yet to say that a particular diet can maintain quality of life or prolong life in most dogs with cancer.
The most important consideration for your dog right now is that you keep his stools soft and small and that he otherwise get a generally healthy diet. You might consider a low-fiber diet that would reduce the volume of stool he produces. You can check with your vet about specific diets they may have. Unfortunately, it’s often difficult to determine the fiber content or other relevant nutritional factors from the label on most commercial diets.
You could also consult a veterinary nutritionist for advice about specific commercial diets or formulating a homemade diet, especially if you reach the point where your friend is losing weight or has less of an appetite. You can check with the nearest veterinary college, or try one of these sites:
I think it is also really important to recognize that we don’t want to make things worse when your dog feels fine right now. Experimenting with food has to be cautious because it can ucreates more problems than it solves. We always have to be careful that our need to do something in a scary situation doesn’t led us to do things that make the situation worse. There are some veterinary diets intended for use with cancer patients, for example, but my own experience with them is that they aren’t especially attractive to many dogs, and due to the high level of essential fatty acids (mostly from fish oil, which is thought to have some possible benefits in cancer treatment), they can cause vomiting and diarrhea.
Good luck to both of you!
“And you completely ignore the fact that we are the healthiest, longest lived generation in human history, thanks to science and science-based medicine. ” skepvet
Well, I just couldn’t ignore this tid bit. You make the mistake of mixing quality vs. quantity.
Healthiest in human history? Me thinks that is a wee bit of hyperbole.
Diabetes , cancer, heart disease, all the auto-immune diseases, that the experts have not a clue on the how they started, are off the charts and increasing.
You also state diet plays No part in these. How do you reckon that?
Sorry, but it is a demonstrable fact that humans living in stable, industrial countries like our are the healthiest that have ever lived. The problem is that you are aware of all the health problems we haven’t yet solved, and you ignore all that we have, including those which plagued humans routinely all their lives for most of human history. When was the last time you had hookworm anemia, or a festering sore, or tuberculosis, or polio, or rickets, or scurvy or protein malnutrition, or a malunion fracture, or gangrene, or……? The routine suffering of parasites, infections, injuries, malnutrition, and other ills that not only killed a majority of children before adulthood as well as a large proportion of women of childbearing age (leading to the longer life expectancy we now enjoy) but also caused daily discomfort for most people who survived (leading to a lower quality of life than we now enjoyed) can only be ignored in discussions like these because we have so thoroughly vanquished them that we have no accurate frame of reference.
We still suffer from many ills, and many of them are age-related or associated with how we eat (having too much food being a new problem for most of our species in the last couple of centuries). I never claimed we had achieved perfect health or an optimal diet for everyone. I merely think you are ignoring all the progress and imaging the past as better than it was in order to buttress an argument against science as a guide for health. The facts contradict that argument pretty clearly.
Here’s some actual data on this subject.
Totally agree with you!
I agree with you!!
This sounds much better and makes a lot of sense. 🙂