Please note: We will be closed on Thursday, July 4th and Friday, July 5th, in observance of Independence Day.

Nutrition in Cancer Patients

Nutrition for Pets with Cancer

One of the most common questions I get is whether or not a patient’s diet needs to be changed once they have a diagnosis of cancer.  In addition, because a cancer diagnosis can make you feel powerless and afraid, it is understandable to want to do everything you can to help your pet.  Nutrition is an important part of that care and something you can actively do at home.  Because the internet is often full of misleading or biased information, I would like to provide at least some basic information here.

Unfortunately, there is very limited scientific knowledge about the ideal nutritional modification during cancer treatment for pets (and people).  To me, the most important thing is that your pet eats enough food and that their basic nutrient needs are met.

For most pets with cancer, our goal is to maintain weight, although underweight pets should gain weight and some overweight pets may benefit from losing some weight. Many pet owners feed more treats and focus on making sure that their pet eats heartily after their diagnosis and this can lead to the pet becoming overweight, which at least in studies in rodents and people may make the cancer worse. In addition to calories, nutrients are also important – adding more meat and other foods from your kitchen to your pet’s normal food, or starting to make your pet’s food at home can lead to nutrient deficiencies that can make it harder for your pet to fight the cancer.

The bottom line is that you don’t need to change your pet’s diet just because he or she has been diagnosed with cancer, but it is a good time to optimize your pet’s nutrition by ensuring adequate nutrient and calorie intake for overall health.  While many books and websites tout so-called “cancer diets”, there is no evidence that any one specific diet or diet strategy is better than any other for all pets with cancer (or people with cancer, for that matter!). If your pet is maintaining weight and otherwise doing well, there is no reason that you have to change his or her diet. Pets with cancer can be fed home-cooked diets, commercial diets, or a combination. The challenge with home-cooked diets is that unless they are carefully designed, nutrient deficiencies are common. Since it is hard to know whether the home cooked recipe you are following is truly a complete and balanced diet, I recommend that all pet owners interested in home cooking for their pets with cancer consult with a Board-certified Veterinary Nutritionist to have a balanced diet recipe designed specifically for their pet.

  • UC Davis provides nutrition consults with a board certified veterinary nutritionist.
  • is run by a veterinary nutritionist and can help provide recommendations.
  • JustFoodForDogs is another resource for prepackaged meals and nutritional supplements and recipes.

Raw Diets

Some sources strongly recommend raw diets for pets with cancer but these diets could be very dangerous to your pet. It is important to avoid feeding raw diets or treats to pets with cancer. Raw meat, eggs, and milk carry high risk of bacterial contamination with Salmonella, Listeria, E. coli, Campylobacter, and other potentially dangerous bacteria. Freezing or freeze-drying do not make raw diets safe. While these bacteria can infect healthy pets (and people in the household), pets with cancer may be at greater risk due to alterations in their immune systems. Pets undergoing common types of chemotherapy are particularly at risk as many drugs used for chemotherapy reduce the white blood cells, sometimes dramatically, that are used to fight infections. Concerns over bacterial contamination of food during cancer treatment is not a uniquely pet issue – food-borne infection is also a serious concern in people undergoing cancer treatment.

Carbs and Cancer

There is a perpetuated myth that low carbohydrate diets will “starve” cancer cells.  These low carbohydrate diets have no proven benefit.  I suspect some of this myth has derived from the link between obesity, potentially from the high carb Western diet, and cancer.  The concept of a  low carbohydrate diet as beneficial for cancer patients comes from the fact that cancer cells rely on sugar as an energy source and in theory, a low carbohydrate diet will decrease the supply of sugar and “starve” the cancer. While this is true in a test tube, improved survival or remission duration for pets being fed low carbohydrate diets has yet to be proven in dogs or cats. Similarly, there is also no proof to support the commonly repeated belief that grains are worse for cancer than other sources of carbohydrates. In fact, grain free diets have led to cardiac disease in dogs.

In rare circumstances, some pets develop a condition called cancer cachexia.  Cancer cachexia is caused by cancer cells consuming energy from the patient leading to starvation of the patient, despite a normal calorie intake.  Cachexia causes severe, uncontrolled weight loss. In reality, most dogs with cancer will not develop cancer cachexia. I see this more often in cats, but it is not universal. I believe that higher protein, lower carbohydrate diets may help reverse cachexia in some dogs.  However, high protein diets may be detrimental for some patients, particularly those with kidney disease, or some other medical conditions.  It is best to review the specific dietary needs of your pet with your veterinarian.

Supplements for pets with cancer

Despite the enthusiasm around some products, there is also little evidence to support the use of most supplements in pets with cancer. Moreover, there is little regulation with respect to safety or efficacy of supplements for people or animals prior to marketing. Some of these products may be harmful rather than helpful. Therefore, we are selective when it comes to recommending specific supplements. We recommend products in which there are data demonstrating safety and a reasonable expectation of efficacy based on peer-reviewed scientific studies, safety studies, and/or third-party testing to make sure the product meets label claims with no contaminants.

This link provides vetted sources of supplements:

Omega Fatty Acids:

Omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, serve as natural anti-inflammatories in cells by inhibiting cyclooxygenase. Their use has been studied in a variety of human diseases, including asthma, inflammatory bowel disease and rheumatoid arthritis. There is evidence in cancer patients that these fatty acids can help prevent or reverse cancer cachexia, especially in people with gastrointestinal cancers. Studies also have shown that fatty acid supplementation may reduce postoperative infections and acute radiation side effects in human cancer patients undergoing surgery or radiation therapy.

Omega-3 fatty acids also may be able to kill cancer directly and have been shown to reduce cellular proliferation, angiogenesis and invasion, and increase programmed cell death. In addition, they have been shown to be protective against cancer development in human patients predisposed to colon cancer and are being studied as part of combination treatments for people with colon, breast and prostate cancer.

Despite their exciting potential, limited research exists on omega-3 fatty acid supplementation in veterinary cancer patients. One study evaluated the effects of a diet supplemented with high doses of omega-3 fatty acids in dogs with lymphoma. Improved outcome was seen in a subset of dogs receiving the diet, but not in all patients. Importantly, fatty acid supplementation was well tolerated and did not affect doxorubicin pharmacokinetics in these patients.

Another study in dogs with nasal carcinoma undergoing radiation found lower levels of inflammatory mediators in dogs receiving fatty acid supplements, which might translate to fewer radiation side effects. Further research into potential benefits of omega-3 fatty acid supplementation in pets with cancer is needed to better define their role. The optimal doses of fatty acids necessary to benefit cancer patients also is not known, but may be higher than labeled doses at approximately 100 milligrams/kilograms per day. Side effects are rare, even at high doses, but can include coagulopathy, diarrhea or a fishy odor.

Omega 3 fatty acids significantly improved objective measures of pain, lameness, and joint disease in dogs with osteoarthritis.

When adding fish oil to a diet with lower omega-3 concentrations, be sure to use a supplement that has been independently tested for quality control. and keep in mind the calories and fat that these supplements can add to the diet (fat is 10 calories per gram!). The type of omega-3s likely also matters – common plant-based sources of omega-3s (e.g. alpha-linolenic acid from flax or walnuts) do not have the same effects as the fish and algae-sourced products.

  • At VCSS, we recommend Nordic Naturals. They test all of their products to ensure they are free of environmental contaminants and toxins.

Antioxidants are commonly discussed with regards to cancer and are controversial. There is concern that high levels of added antioxidants from concentrated supplements may help protect the cancer cells from radiation or chemotherapy (which often work by creating oxidative damage). However, supplementing antioxidants from whole foods (such as fruits and vegetables) appears to be safe as long as you avoid ones that are toxic to dogs and cats (e.g., grapes, raisins, onions, garlic, chives, macadamia nuts).

Turkey tail mushroom (Coriolus versicolor)

Turkey tail mushroom is a nutritional supplement that may inhibit cancer cell growth through cell cycle inhibition, immunomodulation and gene modulation. Some human studies suggest that it can improve long-term survival when combined with other cancer treatment modalities.

In veterinary medicine, a randomized clinical trial in dogs with splenic hemangiosarcoma was conducted using the brand I’m-Yunity.  Dogs were treated with varying doses of the product after splenectomy. Results indicated that the herb is well tolerated, and dogs at a dose of 100 mg/kg per day had a longer time to cancer progression, though no difference in survival was found. Further study into the ideal dose and duration of this herb and how it can best be combined with chemotherapy is necessary.

There are many forms of this product available on the market and it is hard to know if the dosing and efficacy is consistent across all products.

  • We carry a turkey tail product from Aloha Medicinals.  Other available recommended products include I’m-Yunnity and K9 Immunity Plus.

OncoSupport by RxVitamins

OncoSupport is a nutritional supplement designed for pets with lowered immune systems due to cancer or illness. It features a natural blend of plant-based antioxidants, vitamins, and immune modulators including mushroom extract, spirulina, selenium, green tea extract, silymarin extract. During cancer or chemotherapy treatment, OncoSupport may help protect the liver and gastrointestinal system and support the immune system.  This product comes in a powdered formulation to be sprinkled over and mixed in with food.

Yunnan BaiYao

This is a Chinese herb blend that has been used in veterinary medicine to reduce the risk for bleeding from hemangiosarcoma or for nose bleeds, when given orally.  I’ve even sprinkled the powder on bleeding skin lesions to help stop bleeding. This product is imported from China and thus its contents are NOT regulated.  Yunan Bai Yao has been used in people for over 114 years. Initially, it was used to curtail bleeding from combat injuries. VCSS has been using this product in patients for several years.


Probiotics have been defined as “live micro-organisms which when administered in adequate amounts confer a health benefit on the host” by the joint Food and Agriculture Organisation (FAO) and the World Health Organisation (WHO). We use probiotics for patients with chronic diarrhea either caused by their disease, or from dietary upset, or antibiotic use.  There is no exact dose for this product, but can range from 5 to 15 billion CFU per day.

  • Proviable Forte is what we carry and recommend. This is 10 billion CFU per capsule and includes prebiotics as well.
  • We also offer Proviable Kits that come with a kaolin and pectin paste for acute diarrhea.

Rx Clay

This product helps reduce diarrhea and support normal stools and digestion in dogs and cats. It uses hydrated calcium aluminosilicate, a natural clay, to help absorb toxins and support the gastrointestinal tract and bowel function. Rx Clay is a hypoallergenic, vegetarian powder given with your pet’s food.

Joint Supplements

There are many products available to help improve joint function, support cartilage matrix, reduce the breakdown of cartilage, and reduce joint pain in pets.  Omega fatty acids, which can be beneficial for joint health, were discussed previously in this handout.  In addition, we recommend glucosamine and chondroitin.

  • We recommend Dasuquin as a reputable source of these products for pets.
  • Adequan (generic ichon) – is an injectable joint supplement consisting of polysulfated glycosaminoglycans. Reduce the swelling and inflammation associated with joint disease to improve lameness
    • Restore synovial lubrication that facilitates movement and reduces local inflammation
    • Repair cartilage and rapidly aid in the production of new cartilage
    • Reverse the disease cycle that leads the loss of cartilage components by inhibiting harmful enzymes that attack cartilage and synovial fluid

Brassicas (Sulforaphane)

This family of vegetables, including broccoli, brussel sprouts, kale and cauliflower, is gaining attention for their potential anticancer properties.

Nutramax has data on dosing and benefits for dogs.  Their product is called Avmaquin which is used to increase sulforaphane levels in dogs using the active ingredient found in broccoli and broccoli sprouts.  Sulforaphane supports cellular detoxification by stimulating Nrf2 which causes production of certain Phase 2 enzymes. Nrf2 upregulates protective enzymes and proteins to help protect cells from oxidative stress. The production of these enzymes also promotes antioxidant activity against free radicals, which can damage DNA, proteins, and lipids.


Cannabinoids are a consideration in managing pain, anxiety and poor appetite in pets.  However, there remains limited scientific data on dosing, toxicity and benefits.  We cannot legally prescribe these products.  If you choose to use them, we recommend consulting with a reputable dispensary and making sure products are from organic sources (pesticide free).  Ask us about serotonin syndrome, a potential life threatening complication seen in dogs taking CBD.


Curcumin, the principal compound in turmeric, has been shown to inhibit cancer cell growth in vitro by many mechanisms, including inhibition of cell-signaling pathways. Unfortunately, curcumin and its metabolites are poorly bioavailable and travel with minimal absorption through the GI tract. For this reason, most over-the-counter forms of the supplement are not expected to be clinically useful. Some suggest that adding black pepper to curcumin can increase absorption.  There is no established dose for this supplement. Too much curcumin can cause stomach upset, gas and bloating, but is otherwise considered a safe supplement.

SAMe and Milk Thistle

Liver function is important in the activation or metabolism of many chemotherapy drugs. Some chemotherapeutic agents also can be directly toxic to the liver, and CCNU is the most severe hepatotoxin used in veterinary oncology. Up to 84 percent of dogs that receive CCNU therapy will develop elevations in liver enzymes during therapy, and 7 percent will develop liver failure.

SAMe and silybin, the most potent flavonoid from the milk thistle plant, are beneficial in treating and managing liver toxicity.  We recommend that all patients on CCNU be taking a liver supplement such as Denamarin (SAMe and silybin)  or HepatoSupport (silybin, sylmarin, DL methionine, and B Vitamins).

What if my pet is not eating well?

If your pet is not eating well, you should offer an energy dense diet that he/she likes. Feeding enough calories is the most important means to address nutritional concerns. Providing a palatable diet that your pet will eat consistently is more important than providing a specialized diet. There are a few highly palatable, energy dense, ‘recovery diets’ that your dog may like including Hill’s Prescription Diet a/d, Iams Maximum Calorie, or Royal Canin Recovery RS. Other diets that may be considered include canned or dry kitten/ puppy foods and diets for active dogs. Heating foods so that they are warm to the touch can enhance the smell and may encourage food intake. In some cases ‘recovery diets’ are not recommended especially if your pet has kidney, liver, or pancreas problems. These diets should not be used for long periods of time. Once your pet is eating more consistently he/she should revert back to a regular type of food (i.e. adult maintenance, senior or active adult). It is important to discuss these changes in diet with your oncologist or primary care veterinarian. There are appetite stimulants that may be prescribed, as well as anti-nausea medications and antacids that can be useful in pets that are not eating well. Please inquire with your veterinarian.

What about ‘people food’?

Feeding ‘people food’ can often stimulate your pet’s appetite. You can offer a variety of foods such as cooked unsalted meats (roasted, boneless, skinless chicken; pan brown ground turkey or ground beef), cooked eggs (scrambled or hard boiled), cottage cheese, rice, bread, pasta, white or sweet potatoes, oatmeal, cereal crackers, baby food, or other foods. Some pets like sweet carbohydrates such as flavored oatmeal or sweet potatoes better than bland carbohydrates. Adding a small amount of yogurt, animal fat, oil, margarine, or grated cheese can enhance the flavor. Chicken or beef broth can be used as gravy; however, make sure that it does not have garlic or onion in it. Dairy products should be introduced to your dog slowly to make sure that gastrointestinal upset does not develop.

What to avoid: Never feed your dog raisins, grapes, garlic, onion, chocolate, or artificial sweeteners (xylitol), since these can be toxic. If your dog is eating an unbalanced diet for a prolonged period of time (greater than 2 weeks), vitamin/mineral supplementation is recommended. Cats should not be fed anything with onions or garlic.

Have questions? Need to make an appointment?

The Veterinary Cancer & Surgery Specialists team is here to help!