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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Is Your Dog’s Food Helping or Hurting?

Updated: October 10th, 2018

dog-food-dog-cancerOne of the most important things you can do for your dog with cancer is improving his or her diet, which is why Dr. Demian Dressler, author of The Dog Cancer Survival Guide, made food the exclusive focus of step four of his five step approach to cancer care. But how far do you have to go? There is a lot about the relationship between food and health that we still have to discover. But we do know that diet matters: according to this study, 85% of human cancers are a direct result of diet and lifestyle choices, and roughly 30% of cancers can be avoided by improving diet alone.

Because of our physiological similarities to dogs (dogs are the preferred test subjects for human cancer research) if this is true for us, it is probably also true for them. Commercial dog foods are convenient and relatively inexpensive, but most of them – including some “scientifically-formulated” and “premium” brands – are not particularly good for your dog. Dr. Dressler doesn’t think all commercial dog foods are bad, of course. But he does warn against foods that have been processed at extreme temperatures, and also against foods that contain nitrites, nitrates, and ethoxyquin. (For references on the following topics, please see the scientific references page about food and cooking carcinogens for more links to published papers.)

High Temperature Processing

Most dry dog foods are made by using extremely high temperatures in combination with special machines called extruders. The food mixture is pushed through an extruder to make the kibble shape, and then heated. The result is what we call kibble.

The problem with this, for dogs with cancer, is that those high temperatures produce chemicals called heterocyclic amines, which are known to be extremely potent carcinogens. If the food mixture has a lot of starch in it (for example, if corn or wheat is a top ingredient), another carcinogen called acrylamide may also be created. Because they are by-products of cooking, not actual ingredients, these carcinogens don’t have to be listed on the manufacturer’s label.

Listed or not, they are probably found in commercial dog foods, just as they are in human foods like French fries and potato chips. To avoid these carcinogens, Dr. Dressler recommends cooking a home-cooked diet at relatively low temperatures. Guidelines for cooking for your dog are included in both The Dog Cancer Survival Guide (see chapter 14) and The Dog Cancer Diet (which you can get for free at the top of this page by filling in the form).

Can You Use a High Quality Commercial Food?

If you can’t cook, or if you want to use a commercial dog food as part of a home-cooked meal, look for high quality brands like Halo, Solid Gold, Orijen, Blue Buffalo, Canine Caviar and Taste of the Wild. Dehydrated brands are also a good idea, because they do not heat the food at all, and you use warm water to reconstitute it at home. (The Honest Kitchen is a favorite at Dog Cancer Vet because so many of our dogs love the taste.) You might also consider partially cooked or frozen brands.

Nitrites & Nitrates

Another no-no for dogs with cancer are nitrites and nitrates, the preservatives so often found in processed meats (think hot dogs) and also in many brands of dog food. These preservatives extend shelf life, and by themselves seem to be harmless. But once combined with naturally occurring chemicals in the stomach, studies in rats, dogs and people show that they can form N-nitroso compounds, which are known carcinogens. Before giving your dog any food or treats, including human foods, check and see if there are nitrites and/or nitrates.


There’s one more thing to check on your dog food’s label. Look for ethoxyquin, another preservative. While it doesn’t seem to be a problem by itself, it’s been shown in rats and humans to have an effect on carcinogens. In other words, it can increase the bad they do. In one human study it caused kidney damage and pre-cancerous changes, which is why Dr. Dressler recommends avoiding it for dogs with cancer. By the way, you should also check for “fishmeal” on the label, because federal law requires fishmeal be preserved with ethoxyquin. If there is fishmeal, there’s ethoxyquin. Here’s a link to the scientific reference page for ethoxyquin.

Home-Cooked Diet

With the pet food recalls over the years, and a wider appreciation and understanding of how diet impacts health (some of which is due to people like Dr. Dressler “rocking the boat”), we’re starting to see an increase in commercial foods with high protein, low-carb ingredients like those Dr. Dressler recommends in his home-cooked diet. It all gets very complicated, because labeling laws are not necessarily clear, and there is a lot of confusion about what truly is best.

This is one of the reasons Dr. Dressler recommends a home-cooked diet supplemented with a multi-vitamin, so you really do know what your dog is eating. Another plus is that your dog will probably love to eat the “people food” you make for him or her. The guidelines and a base recipe most dogs love to chow down are in chapter 14 of The Dog Cancer Survival Guide.

Making It Easier

We know that using a commercial food can be easier than cooking for your dog. One trick we have here at Dog Cancer Vet is to make big batches of food all at once – a month’s worth, for example – and then freeze it. That way we have the convenience of not having to prepare fresh food every day, and also the peace of mind of knowing that our dogs are eating excellent food at each meal.

If you are already cooking for your dog, that’s great. You might want to check your own recipe against Dr. D’s guidelines – and also check with your veterinarian to be sure that your dog’s diet is well-rounded and complete, and doesn’t interfere with any other health issues he or she may have.


If you cook for your dog, you should definitely add a multivitamin. Commercial dog foods are required to contain the full range of the daily vitamins and minerals your dog needs, and you don’t want to accidentally deprive him or her of necessary daily vitamins and minerals. And while Dr. Dressler doesn’t think mega-doses of most supplements are helpful, he does offer plenty of evidence in the literature for making sure your dog is getting all of the necessary vitamins and minerals, every day, because daily allowance of these substances can help the body as it deals with the cancer.

In addition to the information in The Dog Cancer Survival Guide, there are a couple of Ask Dr. Dressler webinars dedicated to diet and dog food choices. And those are all in The Dog Cancer Kit, which we highly recommend to anyone dealing with dog cancer.

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Best Wishes & Doggy Kisses from Our Homes to Yours,

Dog Cancer Vet Team

(The Team of Dog Lovers Who Understand What It Means to Have a Dog with Cancer)

Leave a Comment

  1. Linda Akin on July 17, 2023 at 9:22 am

    My dog, Oreo, he is 15+ years old and has just recently (last week) been diagnosed with OMM. I don’t know much more about the cancer diagnosis/prognosis other than that at this point. I have just finished reading Dr. Dressler’s book The Dog Cancer Survival Guide, and am looking at making Oreo’s food, and getting him going on the nutraceuticals you recommend. However, this week I just got in an auto-order of Dr. Marty’s Nature’s Blend/Active Vitality dog food, 3 bags/4 weeks supply. I noticed on your website Dr. Marty’s Food was not on the recommended list of foods in place of homecooked meals, and I was wondering why. Is it because of the carrots, pea protein on the list of ingredients, or something else? I was hoping to be able to use both for Oreo at least until we use it up. What are your thoughts? I appreciate your quick response.

    • Molly Jacobson on August 24, 2023 at 4:36 am

      Hi Linda! Dr. Marty is a great vet! I’m not sure why his food isn’t included where you saw recommendations, but it’s not due to not trusting him. I would personally avoid a formula that included legume (pea) as a source of proteins, as well as carrots, due to the starch content. But you can ask his company which of their formulas is lower in carbs — perhaps there is one that could work. There really isn’t a commercial food formulated with the low carbs Dr. D likes to see that I know of. However, using a good trusted brand of dog food that is complete and balanced is always a good idea.

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