Diet & Nutrition for Cancer

The topic of diet and nutrition for canine cancer patients is a huge area of interest and unfortunately, there is a lot of disagreement between vets, both holistic and conventional, regarding the best diet to ensure optimal health. This section is not meant to be an exhaustive discussion of cancer diets, but focuses on five key elements to a good cancer diet for your pup. You should use this information as a starting point to talk with your vet about how to design a cancer diet that is best for your pup’s individual health profile and cancer type.

5 Keys to a Good Cancer Diet:

More Protein, Less Carbs

Several years ago, Dr. Greg K. Ogilvie, oncologist at Colorado State University College of Veterinary Medicine and Biomedical Sciences, and his team conducted intensive research into the dietary needs of canine cancer patients. The results of this research have served as the foundation for the current dietary recommendations for dogs with cancer, and led to the creation of the only commercial dog food clinically proven to improve outcomes for dogs with lymphoma, nasal and oral cancers – Hill’s n/d (neoplasia diet).

In short, Dr. Ogilvie’s research found that cancer cells easily metabolize simple carbohydrates (including sugar), and use them to produce energy and reproduce. However, tumor cells cannot readily use fats. So, a diet low in carbs and high in quality protein and fats will essentially help to starve the cancer cells and reduce the likelihood of cancer cachexia, or wasting as a result of depleted body fat stores.

Many vets will recommend Hill’s n/d for cancer patients because it is clinically proven to improve outcomes, although the clinical results are only confirmed for lymphoma, nasal and oral tumors. Hill’s n/d is a prescription diet available through any veterinarian. It has what is thought to be an optimal ratio of proteins (37%), carbs (21%) and fats (32%) as well as additional Omega 3 Fatty Acids in the form of fish oil (7%) and an amino acid called Arginine (3%).

There are some drawbacks to Hill’s n/d though, that lead many pet guardians to choose other options. First, it is a relatively expensive diet, especially for larger breeds. Secondly, it only comes in canned formula because of its high fat content. As a result, some picky eaters may not like the taste of it if they have been raised on kibble all their lives. Third, and most importantly to those who wish to feed their dog as naturally as possible, the quality of the ingredients in n/d are not ideal, as animal by-products are used to produce this food.

Fortunately, there are many new commercial foods on the market that are low in carbohydrates and use high quality protein sources while also including healthy ingredients like Omega 3’s, probiotics and organic fruits and vegetables. Top quality brands include Innova (Evo), Merrick (Before Grain) and Wysong, although new holistic dog foods are cropping up all the time. The key is to read the ingredients and the nutritional breakdown. Stick to brands that use little to no grain and organic ingredients whenever possible.

Another option, as recommended in his book The Natural Vet’s Guide to Preventing and Treating Cancer in Dogs, Dr. Shawn Messonier suggests using a high-quality brand of cat food for your pup with cancer as cat food contains a higher fat content than dog food. Brands he recommends include Eagle Pack, Nature’s Variety, Wysong, Innova, California Naturals, Halo and Old Mother Hubbard.

Home cooking for your dog is also a great option, and can be used exclusively, or to supplement whatever commercial brand of dog food you select. The key to home cooking is choosing the best quality ingredients you can afford, and to plan ahead. It’s easy to cook a great meal for your dog while cooking your own family’s dinner, or to make a week’s worth of food during the weekend when you have more time, and freezing individual portions to use throughout the week. According to Laurie Kaplan, author of Help Your Dog Fight Cancer, her dog Bullet, who successfully beat lymphoma, ate a homemade diet of 75% protein (chicken, beef, turkey, lamb, eggs or even tofu) and 25% vegetables (pulverized, grated or lightly steamed) throughout treatment (along with fish oil and several other supplements), and stayed in remission for the rest of his life.

Vegetables that are great to include in a cancer fighting diet include kale, broccoli, carrots, cabbage and fresh garlic. Please Note: Garlic should be used in moderation, as too much can potentially be toxic.

Some pet guardians will also choose to feed a raw diet using these same approximate proportions, as many of us have been convinced of the benefits of raw foods, which naturally contain more enzymes, vitamins and minerals than cooked food. This is a personal preference and the topic for another discussion. The key thing to remember is that no matter what diet you select for your pup, limit simple carbs and toxic chemicals and preservatives as much as possible, and focus on providing high quality protein and fats as the foundation for a good cancer diet. And, make sure your dog enjoys his or her meals!

If at any point in treatment your dog stops eating, or becomes overly finicky about their food, resist the urge to be the food police. Because weight loss and wasting can be such a serious issue in cancer patients, it is usually more important to get your dog to eat something, than to remain too strict about nutrition. Enjoying food is an important part of our companion animals’ quality of life, so keep that in mind and don’t panic if you need to tempt your dog with an occasional “treat” in order to help him or her maintain a healthy weight, take their medicines/supplements or stay interested and enthusiastic about life.

Omega 3 Fatty Acids

A diet high in fat has shown to provide the most benefit to canine cancer patients, because cancer cells have difficulty using fats for energy, and also because cancer cachexia, or weight loss despite the amount of calories consumed, is caused by depleted body fat stores and can be very hard to reverse once it develops. The type of fats consumed though, do matter significantly. In the research conducted at Colorado State University, Dr. Ogilvie and his team found that Omega 3 Essential Fatty Acids (EFA’s), specifically in the form of fish oil, “may prevent the development of carcinogen-induced tumors, the growth of solid tumors, as well as the occurrence of cachexia and metastatic disease in experimental tumor models. Fatty acids of the n-3 series have [also] been shown to normalize elevated blood lactic acid and insulin levels in non-malignant conditions.” In contrast, Omega-6 fatty acids “appear to enhance tumor development and metastases.” (Nutrition and Cancer: Frontiers for Cure!)

Look for high quality fish oils or EPA/DHA supplements that are free of mercury or other toxins, are fresh, and have a good ratio of EPA to DHA (with a high level of DHA).

Please Note: Stay away from Cod Liver Oil for this purpose, as Cod Liver Oil has a high level of Vitamin A, which can be toxic in high doses, and always store your fish oil supplements in a cool, dark place. Do not add before cooking, as heat rapidly destroys the benefits of Omega 3 fatty acids. Also, fish oil supplements can have a blood thinning effect, so be sure to tell your vet about any supplements you are giving your dog, especially if your pup will be having surgery.

Amino Acids

As with so many other things, cancer also affects levels of certain amino acids in the blood, which can lead to further health problems. Because of this, supplementing your dog’s diet with the amino acids Arginine and Glutamine can be helpful. Arginine helps to reduce tumor growth and metastasis, and Glutamine helps to prevent wasting and can also help to prevent some of the common gastrointestinal side effects of chemotherapy. You may find that some recommended cancer-supplements already contain one or both of these amino acids, so always read the labels. Please Note: Do not give your dog a Glutamine supplement if they have epilepsy or are on anti-seizure medication.


Whether given as a supplement or as part of a diet rich in fruits and vegetables, antioxidants help the body in many ways. Among their many benefits, antioxidants can induce cancer cell death, prevent cancer cell DNA reproduction, improve the body’s immune system response, and block enzymes used for cancer cell growth. However, there is conflicting research about how antioxidants interact with chemotherapy and radiation.

Some research indicates that antioxidants can help improve the effectiveness of conventional cancer treatments and decrease typical side effects. Other research suggests the opposite -- that antioxidants actually decrease the effectiveness of chemo and radiation, although it’s not clear at what exact dosages they start to interfere with these conventional treatments. Because of this conflicting research, to be safe, it is recommended that if you are giving your dog an antioxidant supplement, you should discontinue the supplements for 48 hours before and after a chemo or radiation treatment. If you dog is getting weekly treatments, this may mean that most days of the week, your dog is not getting these extra antioxidants.

PRIMARY ANTIOXIDANTS – The most powerful and critical ones to include in your dogs’ cancer diet.

Vitamin C

Try to choose one from a natural source including bioflavanoid co-factors. There are several different types of Vitamin C including Sodium Ascorbate, Calcium Ascorbate and Ascorbic Acid. All will work, but they all have slightly different “personalities.”

Animal nutrition expert Kymythy R. Schultze, CCN, AHI in her book Natural Nutrition for Dogs and Cats, provides the following guidelines for each type of Vitamin C.

Calcium Ascorbate – Good for most pets but bitter, so you may have to gradually increase dosage.

Sodium Ascorbate – Most mild tasting, but can contribute to alkalinity when used in large doses. This can lead to problems like urinary tract infections.

Ascorbic Acid – Very acidic, which may cause stomach upset in some animals, and also very sour which some dogs may not like.

The correct dose of Vitamin C for your dog is very hard to identify because the body has varying needs for this Vitamin and will self-regulate if it gets too much, meaning that you cannot overdose on it, but it is easy to underestimate how much the body really needs, especially under the stress of cancer. As a result, it is recommended that you increase your dog’s Vitamin C dosage “to bowel tolerance.” Gradually increase your dog’s dosage until you find that their stool starts to become softer, and then back off the dose to the last tolerated amount. Of course, most dogs will experience periods of diarrhea or soft stools at some point during cancer treatments, so it may be hard to identify the true cause. In this case, trust your instincts and gauge your Vitamin C dosage according to what feels comfortable to you.

Vitamin E

As with Vitamin C, Vitamin E also comes in several different forms, each having specific properties and benefits. As a result, it is best to choose a supplement with “mixed tocopherals” for maximum benefit. Wheat germ oil is a good natural source of Vitamin E, but is prone to becoming rancid, so be sure to only use high-quality, fresh wheat germ oil.

Vitamin A

Dogs can synthesize their own Vitamin A from beta-carotene found in vegetables. In its pure form, however, Vitamin A can be toxic, so be cautious if you are using a Vitamin A supplement rather than supplementing with vegetables high in beta-carotene (such as carrots, pumpkin, sweet potato or collards). This includes if you are using Cod Liver Oil as a Vitamin A supplement. If in doubt, err on the side of caution. Also, according to Dr. Martin Goldstein in his book, The Nature of Animal Healing, some research suggests that Vitamins A and E may compete for absorption in the intestines. As a result, he recommends not giving Vitamin E and A supplements at the same time.

SECONDARY ANTIOXIDANTS – May also be beneficial depending on your dog’s specific health situation.

Coenzyme Q10

This supplement supports the heart and is specifically used with chemotherapy to reduce the cardiotoxic effects of the drug Doxorubicin (Adriamycin). If you have a breed that is more prone to cardio side effects, such as a Great Dane, Rottweiler or Boxer, you will definitely want to add this supplement to your dog’s regimen.

Vitamin D

Known as the “sunshine vitamin,” dogs have the ability to synthesize some of their own Vitamin D from being exposed to sunlight, just as humans do. The many benefits of Vitamin D are still being uncovered, and some research suggests that in addition to balancing calcium and phosphorus in the body and keeping bones healthy, Vitamin D may also help to prevent, and fight cancer. Many Vitamin A supplements also include Vitamin D, including Cod Liver Oil, so depending on the supplements you are using, your dog may already be getting a Vitamin D supplement.


Selenium is a mineral that acts as an anti-oxidant and according to the American Cancer Society, it may “help prevent the development and progression of cancer.” Only a small amount is needed in the body however for results, and too much can be toxic. Best dietary sources for Selenium for dogs include liver, kidney, poultry and whole grains.

There are many other herbs and supplements that have antioxidant properties, many of which support specific organs of the body. Antioxidants are a safe and effective way to help boost your dog’s ability to fight cancer. However, as mentioned above, antioxidants can still have interactions and depending on the cancer treatments your dog receives, your vet may prefer to have you discontinue an antioxidant regimen prior to or after a specific treatment to help ensure that the cancer treatments are as effective as possible. To design an antioxidant formula that’s right for your dog, and to prevent any possible interactions with chemotherapy or radiation treatments, it is best to consult with your veterinarian or a holistic vet.

Digestive Enzymes

When a dog has cancer, it can profoundly affect their body's ability to process and absorb nutrients in their food. This is a key cause of cancer cachexia, which occurs when the body is taking in enough calories but continues to lose weight. As dogs lose fat and muscle mass from cachexia, their ability to withstand the stress of typical cancer treatments is compromised. Digestive enzymes, therefore, can be extremely valuable because they help the body to break down food, making it easier for the body to absorb nutrients. This means less effort expended on processing food, and more energy that can be devoted to fighting the cancer in their body. In addition to helping to increase or maintain body weight, this improved access to calories and nutrition can also translate into increased overall energy levels.

A good digestive enzyme product should include 4 types of enzymes -- protease, cellulase, amylase and lipase. According to Dr. Shawn Messonier, cellulase is especially important if you are adding more vegetables to your dog's diet, as this enzyme specifically helps your dog to break down plant material and release essential nutrients that are often bound by fiber.

You'll find digestive enzymes at most pet food stores nowadays, and they are one of the safest, most beneficial and least expensive supplements you will find. One of the most common brands is called Prozyme. Available in powdered form, you can simply sprinkle 1/4 teaspoon of Prozyme on each meal. Please Note: Because digestive enzymes are destroyed by heat, they are not found in the vast majority of commercial diets, and should never be added to hot or warm food or mixed with warm water.