Dog Cancer Diet Guidelines

What Do Dogs with Cancer Need to Eat?

There is arguably not a more important time in your dog’s life for need of a complete and balanced diet than when they have cancer. “Complete” means that the diet provides all of the nutrients your dog needs, and “balanced” means that the nutrients are provided in the correct amount – not too much, and not too little. The ideal dog cancer diet is complete, balanced, and packed with nutrition.

Let’s take a look at the official guidelines for dog diets as established by the federal government in the U.S.

AAFCO Guidelines for Dog Diets

Almost all commercially available over-the-counter diets for dogs meet the minimum nutrition amount guidelines as established by the Association of American Feed Control Officials (AAFCO).¹

Dog food manufacturers can meet these guidelines by either of these methods:

• Formulating the food to meet AAFCO nutrient profiles – this means the pet food company does the math when they create the recipe to make sure it aligns with AAFCO’s requirements for how much of each nutrient must be in the food, and/or they analyze the finished diet to confirm that it contains nutrient levels consistent with AAFCO’s requirements.

OR

• Performing feeding trials aligned with AAFCO’s guidelines – feeding trial requirements for adult dog food state that at least 8 dogs (but up to two can be removed from the trial once it is underway) must be able to maintain their body weight and have no significant changes in four basic blood parameters during the 6 months of the trial.

Nutritional Adequacy Statements

Your dog’s food should have a “nutritional adequacy statement” on the label that indicates which of these two methods was used to determine that the food is complete and balanced for a specific life stage.

AAFCO recognizes growth (puppy), reproduction (pregnant and nursing female dogs), and adult life stages – and the nutrient requirements for dogs differ by which stage of life they are in. It is important to feed a food that is formulated for your dog’s current life stage.

Remember that AAFCO does not approve, certify, inspect, or regulate pet food. But companies can choose to follow their nutritional profile guidelines, and the AAFCO nutritional adequacy statement will tell you that the company has done so. States determine independently whether to adopt and enforce these guidelines.

If you use a commercial diet, it is important to see those AAFCO statements, to know that the food will have the minimum nutritional profile set by AAFCO.

Cancer Diets Address Changes in Cancer Dogs

When your dog develops cancer, there are a number of changes in her body chemistry, physiology, and metabolism.²

• These changes can lead to cancer cachexia, which causes weight loss – not only of excess body fat, but also of needed lean muscle mass.
• Cancer (and its treatments) can also cause a decrease in appetite, which further worsens this unwanted weight loss.
• When your dog doesn’t want to eat, it’s difficult to make sure she is getting all the nutrients she needs.³

Does a Dog Cancer Diet Really Help?

Starting your dog on a dog cancer diet – whether that is a new commercial food, a homecooked diet, or something in between – is very common.

Not every veterinarian thinks that a change in diet will help cancer enough to make it worth the research and planning. They may also worry that dogs simply won’t like the new food or will get gastrointestinal problems because of changes in diet. Why rock the boat, when so many other treatments might help more?

All of that may or may not be true on an individual level for individual dogs, but dog lovers clearly don’t agree with this stance. Because each dog is unique, and cancer affects individuals in different ways, every dog affected with cancer needs individualized nutritional interventions. Many dog parents recognize this and want to use nutrition to their dog’s benefit after a cancer diagnosis.

In one study of 75 dog guardians whose dog(s) had cancer, 90% changed their dog’s diet in response to the cancer diagnosis.³

Regardless of whether most veterinarians approve of a change in diet, dog lovers clearly want to try it.

Let’s look at some different approaches to diet.

Commercial and Homemade Options

Commercial diets are typically produced in mass quantities, and are available in dry (kibble), canned, semi-moist, dehydrated, freeze-dried, or raw.

Because many of these are processed and packaged for relatively long storage (either on the shelf or in the freezer), they offer convenience.

Most of these diets adhere to AAFCO standard nutrient profile requirements, and because they are complete and balanced, are often recommended after a cancer diagnosis.³

Although in 2008 more than 90% of pet owners in the US and Australia fed their pets mostly or only commercial diets,⁵ many kibble and canned foods list some type of carbohydrate (corn/corn meal, wheat, or another flour) as the first ingredient. This is not ideal when feeding your dog with cancer.²

Homemade Dog Cancer Diets

Homemade diets offer flexibility and total control over what goes in your dog’s body, using fresh, whole food ingredients – so they often taste better to your dog, too, which may help to stoke her appetite. That alone can help to counter cachexia, and also contribute to quality of life.

Many people whose dogs have cancer report that they make their dogs’ food at home, whether cooked, raw, or some combination.³

However, when homemade diets come from untested sources (social media, word-of-mouth, or with no recipe whatsoever), they can easily be unbalanced and/or incomplete, resulting in nutritional deficiencies or excesses that can lead to health complications.⁵

One influential study that evaluated dietary factors in 86 healthy female dogs and 102 dogs with mammary cancer found that 67% of the total caloric intake of the dogs with cancer came from homemade foods, compared to 33% in the healthy dogs.

However, the study also noted that a higher percentage of dietary fat was also correlated with higher incidence of tumors and dysplasias. Was the issue the homemade diets (which included dogs receiving table scraps and treats), or the overall nutrient deficiencies in the diet?⁶

If you are using a homemade diet, please be sure that it is nutritionally balanced for your dog’s age, activity levels, and other health conditions in addition to cancer. We will get into details below.

What We Know from Cancer Diet Research

Cancer cells metabolize differently than healthy cells, so the raw materials you give your dog’s body (in the form of food) have an impact on that metabolism, and how well his body can weather the storm.^2,7

Dietary strategies proposed for dogs with cancer have included low-carbohydrate diets, keto diets, grain-free diets, raw food diets, and dietary supplementation with omega-3 fatty acids.^1,2

Overall, evidence shows that diets low in simple carbohydrates with moderate amounts of protein, fiber, and fats (with an emphasis on optimal levels of omega-3 fatty acids in particular) are beneficial to dogs with cancer.⁷

Let’s look at some of these items in more detail.

Carbs and Cancer

All cells in the body need an energy source to do their jobs, repair damage, grow, and reproduce.

• Carbohydrates provide glucose, an immediately available energy source. If it is not needed at the moment, glucose is stored as glycogen for later use.
• Fat in the diet also provides an energy source for cells, in the form of ketone bodies.

In many types of cancer, the cancerous cells are unable to use ketone bodies as fuel, so they rely exclusively on glucose.

The Warburg Effect

Cancer cells exhibit something called the Warburg effect: they need even more glucose than normal cells do, so they “burn” through it quickly. They use a different metabolic pathway than normal cells use, and this results in excess production of an acid called lactate.⁹

The buildup of lactate makes the environment even more favorable for the cancer to grow and less favorable for the immune system to knock it out.¹⁰

So, by limiting the amount of carbohydrates in your dog’s diet, you could help “starve” the cancer cells by reducing their fuel source, and help your dog’s body better fight the cancer.

Please note that “starve the cancer cells” is a common phrase you’ll hear, but it’s not entirely accurate that cancer cells will be completely deprived of food if you limit carbohydrates. It will reduce their fuel, but not necessarily “starve” them.

How Many Carbs Are Good for Dogs?

Dog lovers often wonder just how many carbs dogs should have in general, as well as when they have cancer. What do we know about this?

The National Research Council determines the nutrition guidelines upon which AAFCO’s nutrient profiles are based. AAFCO requires commercial dog foods to have guaranteed a minimum amount of protein, a minimum amount of fat, a maximum amount of fiber, and a maximum amount of moisture.¹¹

Notice that they have established minimum amounts of proteins necessary for health in dogs, but they have not established any carbohydrate requirement for dogs. Instead, they establish a maximum amount of fiber.¹¹

High fiber foods may be relatively low in carbohydrates, though. This lack of mandatory carbohydrate reporting on dog food labels can lead us to wonder just how many carbohydrates are in our dog’s food.

Do Dogs Love Carbs?

What do dogs themselves think about carbohydrates? We happen to have a study that reveals a little bit about that.

In one 10-day study researchers allowed 15 dogs to self-select their preferred diet among three choices, all of which met AAFCO guidelines:

• high-protein
• high-fat
• high-carbohydrate

The dogs both first approached and first consumed the high-protein diet most often: 64% of the time. They approached and consumed the high-carbohydrate diet least often: only 4% of the time.¹²

So, between the research done into dietary needs for carbs and the dogs own preferences, there is neither a need, nor a desire, for high carbohydrate levels in dog food.

Foods that “Fight Cancer”

Even though there is no dietary carbohydrate requirement for dogs, they will still get them in even the healthiest of foods.

For example, vegetables that are necessary for fiber (roughage is a must), as well as the phytonutrients they provide, and they also have carbs in them.

Cruciferous vegetables are great for dogs with cancer.

Brassica Vegetables

Vegetables from the Brassica genus, like cauliflower, broccoli, and Brussel sprouts, are nutritional powerhouses for dogs with cancer, because they contain over 200 glucosinolates.

Sulforaphane, benzyl isothiocyanate, and phenethyl isothiocyanate are three of the glucosinolates that have been widely studied across several cell types, and they have been shown to both inhibit the growth of cancer cells and make drug-resistant cancer cells more sensitive to chemotherapy.¹³

Omega-3 Fatty Acids

Another addition that is widely viewed as beneficial in the diet of dogs with cancer is polyunsaturated n-3 fatty acids, or omega-3s.

In one study, 32 dogs with lymphoma received a diet supplemented with fish oil (a source of omega-3s) or a control diet with soybean oil. Dogs fed the experimental diet had significantly higher levels of n-3 fatty acids, and increasing n-3 fatty acid levels in blood were significantly associated with longer survival times and disease-free intervals.¹⁴

Leaner Meats

In the study mentioned above that looked at dietary factors in female dogs with mammary cancer, there was a negative correlation with chicken in the diet – meaning, a higher intake of red meat and less chicken was associated with mammary cancer developing, and less red meat with more chicken resulted in fewer cases of mammary cancer.⁶

The balance of omega-3 fatty acids and omega-6 fatty acids may play a role in this association. Factory-farmed animals tend to have higher levels of omega-6 fatty acids, which may be less healthy for dogs with cancer.

Leaner meats tend to have less fat, and therefore, less omega-6 fatty acids.

Cooking and Nutrients

Cooking does affect some nutrients, including those beneficial isothiocyanates in cruciferous veggies, like cauliflower.¹³ Boiling and blanching, in particular, may result in loss of protein and minerals, as well as the phytonutrients. However, steaming, stir-frying, and microwaving minimize these losses in cauliflower.¹⁵

Generally, cooking foods by microwave causes minimal loss of protein, fat, and mineral content. Vitamin loss through microwaving was similar to that of conventional cooking in one study.¹⁶

But another study that looked at 10 different vegetables prepared by four different cooking methods found that the degree of vitamin loss was not consistent among vegetables for any cooking method – and in fact, some vegetables had higher available vitamin content after certain types of cooking.

So, the effect of cooking on vegetables can be quite variable.¹⁷

We may not know enough about how specific foods react to specific cooking methods to make recommendations about how to cook every ingredient you give your dog. (Although we do know about high-heat cooking, see below.)

Cooking and Digestibility

To complicate things further, even though some foods may have higher nutrient content in their raw state, those nutrients might not be readily available to dogs because they are “locked” in a relatively undigestible food – and cooking them may be the key to unlocking those nutrients.

Vegetables and mushrooms contain cellulose (a type of fiber) in their cell walls. Herbivores make the enzyme necessary to break down that cellulose to access the nutrients in the plant cells, but omnivores and carnivores don’t.

By cooking these foods for your dog, you can make them more easily digestible, and that helps your dog absorb more nutrients.

For example, chicken necks, full of small bones, are an excellent source of calcium and phosphorus. Drs. Dressler and Ettinger recommend cooking them until the bones are soft and malleable (don’t stop cooking too early, when they are in the brittle stage – that’s when they can break into sharp pieces that can be dangerous), then mashing the necks and removing any pieces large enough to find, to minimize choking risk. The tiny pieces of softened bone left in the mash are mineral-rich.²

Cooking Temperatures and Carcinogens

Cooking temperatures are an important factor in the safety of your dog’s food, so let’s look at those next.

Heterocyclic amines are compounds that are formed when meat is cooked at high temperatures. These compounds have been associated with cancer in animals and primates.¹⁸

Traditional methods of cooking meat, such as grilling, smoking, and roasting can cause these carcinogenic compounds – heterocyclic amines, and another type called acrylamides – to develop.

Microwaving, steam roasting, or infrared grilling are better options for retaining nutrients while not introducing carcinogens.¹⁹

Concern over the formation of carcinogens during cooking and the high-heat processing involved in manufacturing kibble and canned foods has contributed to interest in raw meat-based diets for dogs.²⁰

But cooking is still a safe option, if it’s done at lower temperatures. Drs. Dressler and Ettinger recommend cooking low and slow, because almost no carcinogens are formed at 212°F, but over 390°F there is increased risk.²

So if you cook for your dog, stick to cooking at lower temperatures to minimize their production: simmer, cook in a crock pot or slow cooker, or use a pressure cooker or instant pot.²

Cooked vs. Raw?

Raw meat-based diets might be an excellent choice for healthy dogs with healthy immune systems.

But dogs battling cancer may have significant immune system compromise – from both cancer itself, and from some of the cancer treatments – that leaves them unable to fend off potentially dangerous bacteria (like E. coli or Salmonella) or parasites that can be found in raw meat.²

Even freezing and freeze-drying don’t necessarily mitigate this risk enough to make these diets the best bet for dogs with cancer.²⁰

The One Commercial Food Designed for Dogs with Cancer

For those who don’t want to spend so much time cooking and thinking, there is one option for a commercial diet designed specifically for dogs with cancer. Hill’s, the pet food company, has stepped into this void twice.

In 1998, Hill’s released Prescription Diet n/d (for “neoplasia diet”) that was designed for dogs with cancer – the first commercial product specifically for this purpose. It was discontinued for a while, but Hill’s is releasing a new product – Prescription Diet ONC Care (“oncology care”) to fill this void.

It is available in the U.S. as of March 2023 and will be globally in 2024.

Hill’s says their new ONC Care diet includes highly digestible proteins and high levels of essential amino acids, along with prebiotics to support the microbiome as an assist for the digestive upset that can occur with cancer and its treatment.⁸

Is There a Definitive Home Cooked “Dog Cancer Diet”

There are no defined nutrient profiles specific to dogs with cancer at this time, so there is not one accepted “dog cancer diet.”

Your dog’s best dog cancer diet is one your dog will eat that meets all nutrient requirements.

It should also offer enough flexibility to use ingredients that address your dog’s changing needs and preferences as he progresses through his journey.²

Every dog – and their cancer – is different.

For example, mast cell tumors release histamine, which can create swelling, blood pressure changes, vomiting, and loss of appetite. Some foods, like tofu, yogurt, and shellfish, are either high in histamine themselves or they trigger the release of histamine in your dog’s body. These would be on the “foods to avoid” list for dogs with mast cell tumors. But they could be fine additions to the diet for a dog with a different type of cancer.²⁰

You can arrive at the ideal diet plan for your dog with cancer by working with a board-certified veterinary nutritionist who can provide valuable information, formulate a diet specific to your dog’s needs, and monitor their response to dietary changes.³

Rough Macronutrient Guidelines

It can be hard to get a home-diet right – it may not be nutritionally adequate on its own, especially if you aren’t using a recipe formulated by a nutritionist, or if you’re not following the recipe exactly.

In a study investigating 27 home-prepared recipes for dogs, none of them met the AAFCO or NRC Recommended Amounts for all essential nutrients.¹

Protein and Fat Guidelines

AAFCO minimums are 18% protein and 5% fat for adult dogs, with no carbohydrate requirement.

But these are minimums, not necessarily ideal proportions.

Higher protein (closer to 40%) and moderate fat (about 15-20%), along with low-carb vegetables (and some fruits) to provide fiber and phytonutrients may be a better target.

Healthy whole grains may round out the diet, especially for dogs with cancer who may have trouble maintaining their weight, as these can be a nutritious source of additional nutrients and calories.

Multivitamins

Multi-vitamins are commonly used to help “fill in the gaps” that may be present in home-prepared diets. But do take care not to blindly over supplement – some vitamins have established safe upper limits.

And some dogs can’t tolerate high doses of certain minerals, even if there if is no accepted maximum recommended amount. For example, excess copper has been tied to liver disease in dogs.²¹ How much copper is too much? Well, there is no defined upper limit. But since this is a problem, don’t supplement copper if your dog’s diet already meets the minimum nutritional requirement for copper.

Especially if you are using a highly-supplemented commercial diet for part of your dog’s daily ration, be aware of what is in his food, and don’t use an extra supplement without guidance. Work with your veterinarian and veterinary nutritionist to ensure your dog’s diet is hitting all his nutritional targets.

Specific Foods to Include

Some foods are worth including regularly in your dog’s diet, especially if she has cancer. Some of these can be added on top of a commercial diet, for example:

• Vegetables from the Brassicaceae family (cauliflower, broccoli, Brussel sprouts) are especially well-known and effective because they have a number of bioactive phytochemicals that help to both prevent and treat cancer.^22,23
• Mushrooms have beta-glucans (β-glucan) in their cell walls that work to stimulate lymphocytes, a big player in immune function.²
  • Some especially great mushroom choices are the “medicinal mushrooms”: Reishi (Canoderma lingzhi), Maitake (Grifola frondosa), Shitake (Lentinula edodes), and Turkey tail (Coriolus versicolor)
• Proteins:
  • Chicken is a great source of protein, including some specific amino acids, as well as vitamins and minerals.
  • Beef is also a rich source of protein and other nutrients, but it is not the best protein option for dogs with mammary (breast) cancer.² As above, high beef intake and low chicken intake has been associated with mammary tumors.⁶
• Other sources include fish (although not a good choice for mast cell tumors), turkey, venison, duck, pork, goat, and lamb.
• Other foods you may wish to include are cottage cheese, oatmeal, virgin coconut oil, brown rice, raspberries, sardines, leafy herbs (parsley, basil), garlic, and ginger root.²

Drs. Dressler and Ettinger recommend these meal-time guidelines in The Dog Cancer Diet, from The Dog Cancer Survival Guide:

• High quality lean protein – full of amino acids, vitamins, and mineral, and helps maintain muscle mass
• Fats and oils – healthy fat is good fat. Fish oil and krill oil are great sources of omega-3 fatty acids, which often need a boost in the diet to balance the often excessive – and pro-inflammatory at high levels – omega-6 fatty acids (chicken is high in omega-6s)
• Vegetables – brighter colored vegetables tend to be higher in cancer-fighting phytonutrients
• Chicken necks are a great whole food source of important minerals like calcium and phosphorus.
• Whole grains – a healthy source of carbohydrate energy. Brown rice and oatmeal are good example.
• A multivitamin – this can help to provide missing elements in your dog’s homemade diet (so it’s important to know what is present and what is missing)
• Healthy additions of toppers and treats: Add flavor to your dog’s meal while sneaking in immune boosting and cancer fighting components – fresh garlic, basil, virgin coconut oil, and fresh blueberries are a few examples.

How Much Should I Feed My Dog?

If you have used commercial diets until now to feed your dog, you are used to seeing instructions on how many cups or ounces of food to give your dog based on their weight.

However, this is not the best way to decide how much to feed a dog. Dogs are highly variable, just like humans are. A couch potato needs less food than an athlete, just like humans.

Dogs with cancer are highly variable, and so is the amount of food that they need. Keep in mind that over-feeding is never healthy, and obesity can contribute to cancer.²

In fact, obesity at one year of age, and one year before their cancer diagnosis, was significantly correlated to the prevalence of mammary tumors in female dogs.⁶

When a nutritionist formulates a recipe, they should provide feeding guidelines for your dog, based on her age, activity level, current weight and body condition, and metabolic needs. Feeding more or less than the recipe was formulated to deliver can result in vitamin or mineral excesses (which could be toxic) or deficiencies (which doesn’t give your dog what her body needs to function).

If you are transitioning your dog from his previous diet to a cancer-fighting diet, do so gradually enough to allow his system to acclimate, usually over a period of about two weeks.²

Hybrid Dog Cancer Diets

If switching to a totally homemade diet seems overwhelming or impractical, fear not – your dog can reap the benefits of some cancer-fighting super foods in addition to her regular commercial diet.

In a study where 75 owners whose dogs had cancer were interviewed, 18% used a combination of conventional and homemade diets.³

There are a number of ways this can look. A few options include:

• If your dog eats twice daily, 1 or 2 meals out of the 14 meals per week are homemade.
• You could make 25-50% of your dog’s bowl at every meal fresh food mixed with her commercial diet, as long as this is complete and balanced (rely on a nutritionist to help you determine this).
• You could add healthy treats or meal toppers to her entirely commercial meals
  • These toppings can add flavor as well as immune boosting cancer fighting properties² so choose wisely – select foods with benefits.
  • The general rule of thumb is no more than 10% of the total diet should be treats and/or toppers, to avoid disrupting overall balance.
  • Avoid overloading any individual vitamins or minerals – too much of a good thing can sometimes be a bad thing.
  • If you are using a commercial food base, know whether any nutrients are approaching safe upper limits, so you don’t inadvertently add more of this nutrient to the bowl. You will likely need to call the manufacturer to get this information.
  • Anecdotal evidence and testimonies from owners of dogs with cancer show that positive outcomes can be observed when toppers are added to commercial food diets.²

Dogs with Multiple Health Conditions

Your dog may have preexisting conditions (or develop other conditions after cancer diagnosis) that will impact many aspects of their cancer treatment, including diet. Some common examples are:

• Kidney disease:
  • Avoid dry kibble. Dogs lose more fluid through their urine in the face of kidney disease, and fresh foods that contain moisture can contribute to hydration.
  • Avoid foods that are high in phosphorus – foods like jerky, sardines, bread, beans, nuts, organ meats and many “regular” dog foods. Phosphorus restriction is accepted as the most critical dietary intervention for dogs with kidney disease.²⁴
  • A protein restricted diet may be suggested, but this is controversial as studies have not consistently demonstrated the same benefits as phosphorus restriction.²⁴
• Pancreatitis:
  • Avoid high fat diets, as they have been associated with pancreatitis.²⁵ If your dog does develop pancreatitis, he will likely need to remain on a low-fat diet for life. Choosing very lean meats is important, so leave the skin off poultry and choose 90% lean (or leaner) ground meats.
  • Dogs that have pancreatitis and cancer may not benefit from a high-fat diet (e.g., keto).
• Allergies:
  • Your dog could have an allergic reaction to any number of things (just as people can). Monitor your dog when trying anything new, and avoid foods your dog has already reacted negatively to. For example, krill oil is not a safe choice if your dog has a shellfish allergy, but there are plenty of other food sources rich in omega-3 fatty acids, such as salmon or other fatty fish, or flax seeds.²

Focus on the foods that are generally “safe”, used commonly, and can help your dog with both cancer and his other conditions. For example, omega-3 fatty acids are part of the management plan for cancer, kidney disease, and allergies.²

Choosing Between Other Health Conditions and Dog Cancer Diet

Many dog lovers panic when their dog with cancer develops kidney problems and needs a kidney-friendly diet, or pancreatitis that requires a pancreas-friendly diet, or new allergies that require a different diet. They worry that feeding their dog a non-dog cancer diet will be harmful and let the cancer progress.

We always have to weigh pros and cons in treating any illness, and this is a tricky one.

In general, the best choice is to modify the diet to accommodate the non-cancer condition, because, frankly, they can kill a dog faster than cancer usually does. Pancreatitis can be deadly, resulting in death within a few days. Kidney and liver failure generally kill dogs much quicker than cancer does. Allergies might not kill a dog, but they sure do make them miserable.

Your veterinarian will be able to explain to you the timelines involved in each of your dog’s health issues, to help you understand why dietary modifications away from cancer fighting foods and towards foods that support organs will help your dog.

In the End, Your Dog Must Eat

The bottom line for feeding your dog with cancer is that eating something is better than not eating anything at all.²

If your dog won’t eat the masterfully crafted (complete and balanced) diet full of cancer-fighting superfoods that you offer him, know that even small improvements in diet can make a big difference – so you don’t have to feed the “perfect” diet to create positive changes.

In general, diets that are low in simple carbohydrates and have moderate amounts of protein, fiber, and fats (with a special emphasis on omega-3 fatty acids) are beneficial to dogs with cancer.⁷ The closer you can get to these parameters, the better.