Nutrition in Pets with Cancer
What diet should I feed my pet? What foods should I avoid? What if my pet is not eating? What about home-made diets? Here are some answers to some ‘Frequently Asked Questions’ asked by owners about diet for pets with cancer.
What diet should I feed my pet during chemotherapy?
The best diet you can feed your pet during chemotherapy is a diet that he or she likes to eat.
It is essential that your pet enjoys his or her quality of life during chemotherapy.
Owners may research that cancer cells prefer to thrive on carbohydrates and that it may be beneficial feeding pets a diet high in protein, fat, calories, and low in carbohydrates. However, at present, there has not been strong scientific evidence demonstrating a survival benefit in pets with cancer. Nevertheless, these diets may help maintain muscle mass in thin cancer patients.
Your pet’s diet should ideally be 'nutritionally complete and balanced', such as a balanced commercial diet (e.g. Hills or Royal Canin) that is appropriate for your pet’s breed and age. Provided your pet eats adequate calories, a balanced commercial pet food will contain the right macronutrients (such as carbohydrates, fats and proteins) and micronutrients (such as vitamins and minerals) for your pet. There is no need to add meat, protein or anything else to your pet’s diet. There is also no need to completely restrict carbohydrates from your pet's diet.
In 2023, Hills introduced a new cancer support diet called Hills Onc Care, available in both wet and dry formulations for dogs and cats. This diet is designed to support cancer patients due to its high palatability, complete and balanced composition, high calorie/energy density, richness in omega-3 fatty acids, high-quality proteins, and the presence of L-carnitine and other essential amino acids. It also includes prebiotic fibers to support gastrointestinal microbiome and consistent stool quality. Moreover, it is not restricted in carbohydrates. This diet has not been shown to improve cancer survival. However, it can be beneficial in patients that are not eating well or losing weight, provided pets enjoy eating it. Click here for further information. Click here to view the palatability study.
What foods should I avoid during chemotherapy?
1) Avoid feeding raw meat, bones or eggs during chemotherapy.
A raw diet will contain more bacteria for your pet's immune system to fight than cooked food and can increase the risk of gastrointestinal side effects, infection and sepsis from chemotherapy.
For example, if your pet has a low white cell count, he or she may be at slightly increased risk of infection and/or sepsis.
2) Avoid feeding a grain-free diet because it can lead to heart disease.
There is no scientific proof to show that a grain-free diet that reduces or eliminates carbohydrates will benefit pets with cancer. There is also no scientific proof to show that grains are the worse carbohydrates.
3) Avoid changing your pet’s diet of all of a sudden, particularly when your pet starts chemotherapy.
If you change your pet's diet all of a sudden, your pet may experience diarrhoea, and it can be challenging for your veterinarian to determine if the diarrhoea is related to chemotherapy or due to a recent change in the diet.
Pets with cancer are already undergoing other stresses and changes.
If you wish to change your pet's diet, consult your veterinarian. The best time to change your pet’s diet is when you and your veterinarian knows that your pet is tolerating chemotherapy. Unless you are changing your pet to a bland diet, if you are changing your pet’s diet, it is best to gradually transition to the new diet slowly—for example, over 3-5 days.
4) Avoid fatty foods.
Unless your veterinarian has prescribed a high-fat food such as Hills a/d, avoid feeding your pet high saturated fat foods such as bacon, bones, sausages and hamburgers, even if your pet is not eating well.
This is important to prevent your pet from developing gut upset and pancreatitis.
Can I feed my pet raw vegetables?
Raw vegetables are fine. In fact, raw vegetables are much better than cooked vegetables, particularly broccoli or other green vegetables.
What if my pet only eats raw meat?
Occasionally, pets will only eat raw meat and will not eat enough cooked meat. Other times owners feel their pet has a poor quality of life and their pet does not enjoy eating cooked meat or a commercial diet.
If this is the case, you can continue to feed your pet raw meat. But it is important to know that your pet will be at slightly increased risk of gastrointestinal side effects, infection and sepsis from chemotherapy.
If you pet has a very low white cell count, sepsis, infection or is experiencing gastrointestinal side effects from chemotherapy, you should not feed him or her any raw meat until the white cell count, sepsis, infection and gastrointestinal signs have resolved.
What if my pet is not eating?
If your pet is not eating, you should contact your veterinarian as soon as possible. Do not leave this past 24 hours as your pet may become dehydrated and run into other problems such as the development of kidney disease.
You can try tempting your pet to eat yummy warmed foods that he or she does not normally eat, such as cooked chicken breast, steak, lamb, tuna or fish.
You can also try hand feeding, patting or talking to your pet when he or she feeds; try feeding your pet in a different area of the house; or have someone different do the feeding. Sometimes a pet will associate its surroundings with an unpleasant experience. Dogs are pack animals so may eat better if you feed your dog with other pets or during your usual family mealtimes. Conversely, some cats like to be fed in a quiet environment away from people and other pets in the household.
Try to make mealtimes as comfortable and stress-free as possible. Try not to schedule mealtimes with medications and avoid pushing food in your pet’s mouth. If you need to medicate your pet with food, try to do so with a small meatball of food and at a different time to the usual mealtimes.
Try to tempt your pet to eat at least four hours apart, because tempting your pet too frequently or when your pet is showing overt signs of nausea or discomfort, can lead to ‘food aversion’, which is where your pet associates the act of eating or the sight of or smell of food with unpleasant side effects such as gagging, nausea, vomiting or pain. It is also important to not force your pet to eat if they do not want to. A pet that should be left alone is a pet that drools at the sight or smell of food, turns their heads away, spits food from the mouth, or buries food.
Your veterinarian may prescribe appetite stimulants and anti-nausea medications to help your pet eat.
In some situations, your veterinarian will recommend temporarily placing a feeding tube. Although most owners do not like this idea, this is important in some pets to reduce the risk of food aversion and ensure your pet is receiving the right nutrients to help combat cancer.
What if my pet is vomiting?
If your pet is vomiting, you should contact your veterinarian as soon as possible, particularly if the vomiting is severe (i.e. more than three episodes) or the vomiting persists for more than 24 hours. Do not leave this past 24 hours as your pet may become dehydrated and run into other problems such as the development of kidney disease.
Your veterinarian may prescribe anti-nausea medications to help stop the vomiting. If your pet is vomiting or nauseated (for example, lip-smacking or drooling), it is best to administer the anti-nausea medications on an empty stomach.
Unless your pet has kidney disease or veterinarian has told you otherwise, withhold any food and water for approximately 6-12 hours, then offer your pet a small amount of water.
If your pet is holding down water for 2-3 hours or if your pet is not interested in drinking, you can offer a small amount of a bland diet such as boiled chicken breast and white rice, Hills I/D, or Royal Canin Gastrointestinal Low Fat. If your pet starts to eat without vomiting, continue to feed this bland diet for the first three days, then gradually reintroduce your pet back to the usual diet slowly over the next 3-5 days.
What if my pet has diarrhoea?
If your pet has diarrhoea, you should contact your veterinarian as soon as possible, particularly if the diarrhoea is severe (i.e. more than three episodes) or the diarrhoea persists for more than 24 hours. Do not leave this past 24 hours as your pet may become dehydrated and run into other problems such as the development of kidney disease.
Ensure free access to water.
Your veterinarian may ask you to fast your pet temporarily. Do not do this without consulting with your veterinarian because it is only recommended in some pets with severe diarrhoea.
Your veterinarian may prescribe a short course of antibiotics, anti-diarrheal medications or probiotics to help resolve the diarrhoea.
Offer your pet a small amount of a bland diet such as boiled chicken breast and white rice, Hills I/D, or Royal Canine Gastrointestinal Low Fat. Continue this bland diet until the diarrhoea has resolved, then gradually reintroduce your pet back to the usual diet slowly over the next 3-5 days.
If your pet is refusing to eat a bland diet, contact your veterinarian as soon as possible.
What if my pet is losing weight?
Pets can lose weight during chemotherapy for various reasons. Cancer causes lots of metabolic changes in the body that can cause pets to lose weight rapidly. Sometimes weight loss or muscle wasting can be difficult or impossible to reverse.
If your pet is underweight, losing weight rapidly, has muscle wasting or cancer cachexia (i.e. profound weight loss due to cancer), you can try the following.
The simplest thing you can do is increase the dietary intake temporarily by 25-30% and increase the frequency of feeding. For example, feeding your pet three to five times daily instead of once or twice daily. Often pets with cancer will require much more than the usual amount in order to maintain his or her body weight. This is because the cancer is also competing for some of the nutrients and alters the normal metabolism and immune system in the body, that cannot be overcome simply by providing the usual calories and nutrients.
Unless otherwise directed by your veterinarian, you can try more calorie-dense diets such as a puppy or kitten food, a high-performance diet (such as lactation, working dog or active outdoor cat diet), or Hills Onc Care (which is a commercial diet that can help pets maintain lean body mass).
You can chat to your veterinarian about adding in fish oils that are high in omega 3 oils such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega 3 oils can help your pet maintain his or her lean body mass (i.e. reduce the amount of muscle loss) and can sometimes improve your pet's appetite. This is not the same as cod liver oil, flaxseed oils and other plant-based omega-3 fatty acids, which are not recommended in pets with cancer.
Divide the daily food intake into as many small meals as your schedule will permit. Small amounts frequently will prevent your pet from developing diarrhoea and can help your pet eat better.
What about home-made diets?
Home-made diets are often challenging for owners to get right. Although you can calculate macronutrients for your pet, it extremely difficult to calculate the right micronutrients for your pet’s age and breed.
Home-made diets that do not contain the right nutrients can lead to nutrient deficiencies and make it harder for your pet to fight cancer.
If you wish to feed your pet a home-made diet, try to ensure it is not the main diet for your pet (i.e. less than one-third of your pet’s total dietary intake).
If you wish to solely feed your pet a home-made diet, seek advice from a board certified veterinary nutritional specialist, who can individually tailor the diet for your pet: https://acvn.org/directory/
Is there any evidence that a cancer diet can make pets respond better to therapy or live longer?
Diet is known to prevent certain cancers. For example, in humans, reducing red meat intake and being a vegetarian lowers the risk of colon cancer. However, once cancer has already developed, unfortunately, the type of diet does very little in treating the cancer. Although cancer cells preferentially thrive on carbohydrates, even if you starve your pet of any carbohydrates in the diet, the cancer will start to use up your pet’s fat and protein stores, which can be detrimental to your pet’s health if your pet does not eat any carbohydrates.
Currently, there is no cancer diet that has shown to improve survival outcomes in pets with cancer, so until there is such evidence, I think it is best to feed a balanced diet, that your pet enjoys.
However, you must meet the basic nutritional needs of your pet. In human cancer patients, malnutrition can increase the risk of complications and decrease survival outcome. Patients with a good nutritional status have improved responses to therapy and a better quality of life. Malnutrition has not been studied in veterinary patients, but it is probably similar in pets.
I hope this information helps pet owners understand a bit more about nutrition in pets with cancer. Remember, the best diet is one that your pet enjoys!