Cancer and Your Dogs Diet
Cancer is when a group of cells in the body grow uncontrollably. They often destroy neighboring tissues and spread to other parts of the body. Cancer can affect your dog by causing a rapid weight loss, often associated with unwillingness to eat. However, nutrition geared at pets with cancer is not just aimed at maintaining a proper weight; it can also increase the quality of life and longevity of your pet. Additionally, it can reduce toxic effects of chemotherapy and lessen the effect of altered metabolic activity in cancerous pets. There is also evidence that specific nutrients can treat cancer directly or indirectly.
Improper nutrition can also increase a dog’s risk of getting cancer. For example, obesity is significantly related to a higher prevalence of mammary tumors and cell dysplasia in growth. Also, dogs eating home-made meals as opposed to commercial foods have a higher incidence of tumors and dysplasia. If you are making your dogs food at home, there are web-sites available online to help you formulate a complete and balanced diet.
Cancer cachexia is a condition in which dogs will loose weight, eat less, and suffer from inflammation. In these patients both the fat and protein stores are lost simultaneously. This syndrome is most likely due to a negative energy balance, which means that the animal needs more energy than it has available to use.
Treatments for cancer can affect a dog’s nutritional status: Surgery is generally used to remove tumors. Operating on the head or neck can directly affect the patient’s ability to eat, leading to difficulty with chewing and swallowing, and risk of aspiration. In these cases, a veterinarian may choose to place a tube, to facilitate feeding. These tubes may be used up to 2 months or more after surgery. If the tumor is in the stomach or intestine, taking out a piece of either organ can affect the absorption of nutrients. Chemotherapy affects several aspects of nutrition. This is because chemotherapy has the greatest effect on rapidly dividing cells, such as those in the GI tract. These drugs may cause nausea, vomiting, and alterations in smell and taste. If corticosteroids are part of your pet’s treatment, you may see excessive thirst and increased urination, leading to a loss of water soluble vitamins. Radiation can affect salivary secretions (decreased production and increased viscosity) causing dry mouth, impaired swallowing and dental disease due to alterations in the bacteria naturally present in the mouth.
The nutrition factors that need to be considered in cancer patients include soluble carbohydrates, fat, fatty acids, protein and some key amino acids like arginine. Feeding high levels of digestible carbohydrates may lead to increased levels of sugar in the blood and urine, liver dysfunction, respiratory insufficiency and hyperlactemia. Glucose and lactate containing fluids should be avoided. Carbohydrate levels in foods for cancer patients should contain no more than 25% digestible carbohydrate on a dry matter (DM) basis.
Fat and Fatty Acids: Some tumor cells can have difficulty using lipids as a fuel source. This means lipids can be used as an energy source for the host. Therefore foods relatively high in fat are better for cancer patients than foods relatively high in carbohydrates. Omega 3 fatty acids have a negative effect on tumor growth whereas omega 6 fatty acids can enhance tumor growth. Use a food with 25 to 40% DM fat, and greater than 5% omega 3 fatty acids and an omega -6:omega-3 fatty acid ratio about 1:1.
Dogs with cancer often have decreased muscle mass, as tumors use amino acids for energy. Dietary protein levels in the food of cancer patients should exceed normal levels. However, if kidney or liver function is compromised, this may not be true. 30-45% DM arginine helps the immune system and may decrease tumor growth.
Other factors
1) Glutamine is an important fuel for cells of the gut. Supplementation with glutamine may improve intestinal integrity during cancer treatments.
2) Branched chain amino acids like leucine, isoleucine and valine have anti-anorexia and anti-weight loss effects, by reducing the negative effects of tryptophan. It may also prevent cancer growth.
3) Some tumor cells use methionine for growth. If possible, methionine should be replaced with homocysteine.
4) Removing asparagines from the diet of dogs with lymphoma (and replacing with L-asparaginase) has caused remission in up to 80% of dogs and cats studied.
5) Vitamin E, Vitamin C, retinoids and glycine fight cancer, add them to the diet.
Bottom Line: If your pet is being treated for cancer, whether surgically or medically, make sure you discuss a feeding program with your veterinarian. Be prepared to purchase a special diet catered to the unique needs of your pet, for example from brands like Science Diet or Royal Canin.
