August 30, 2005
Cancer Causes “Wasting”
Besides changing energy and protein requirements, you also need to consider any health conditions from which your dog suffers, because they can alter its nutritional needs. For example, even long before any symptoms of cancer appear, subtle changes occur in how the affected animal metabolizes carbohydrates, proteins and lipids. These metabolic alterations are called cachexia.
One of the most dramatic changes occurs in carbohydrate metabolism. Normal animals use glucose through an aerobic mechanism in which glucose is broken down to carbon dioxide and water. This results in the production of the maximum amount of adenosine triphosphate. ATP can be considered the body’s energy banker. The bond created when ATP is formed from adenosine diphosphate and phosphate is stored as chemical energy. Breaking that bond releases energy that can be linked to biochemical processes that require energy.
For some unknown reason, cancerous tissue prefers to metabolize glucose in an anaerobic process that results in lactate as its end product. The conversion of lactate into a usable form requires energy. The net effect is an overall energy loss for the animal. Even dogs that have been cured with chemotherapy and surgery retain these elevated lactate levels. Clearly, some fundamental change has occurred due to the malignancy, and therapeutic dietary intervention is required.
[snip left][/snip]Abnormal protein metabolism also is seen in the cancer patient. A significant decrease of a wide range of amino acids suggests high-quality, highly bioavailable protein must be fed to the patient. Lack of these essential nutrients alters many important bodily functions, including gastrointestinal function, surgical healing and, most importantly, the immune response.
Dogs with cancer have lower levels of high-density lipoproteins (the good cholesterol) and higher levels of total triglycerides and very low-density triglycerides (the bad cholesterol). Alteration of lipid metabolism also leads to an increase in fatty acid synthesis. This metabolic abnormality has been linked clinically to immunosuppression, and it does not improve significantly, even after clinical remission from cancer. Some studies, however, show tumor cells have difficulty using fat as a fuel source. This implies that a high-fat diet may be beneficial to an animal with cancer. Omega-3 fatty acids seem to be especially helpful.14
Other nutritional therapies using anti-oxidants such as vitamin C, grape seed extract, vitamin E and vitamin A have proved therapeutic in clinical trials. Selenium, vitamin K, arginine, glutamine and garlic also show promise in the nutritional treatment of cancer.15-18 The use of therapeutic enzymes seems beneficial if used concurrently with other, more traditional anti-cancer treatments. Although the mechanism by which these enzymes function has not been elucidated, some research has suggested they eliminate pathogenic immune complexes.19
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By Susan Thorpe-Vargas, Ph.D. and John C. Cargill, M.A., M.B.A., M.S.