If it seems fishy that some owners supplement their dogs' cancer treatment with fish oil, think again. While conventional cancer treatments like chemotherapy and radiation are often effective, some owners incorporate alternative treatments, such as fish oil supplements, to help slow the development and metastases of certain cancers.
Omega-3 Fatty Acids
The secret ingredients in fish oils, according to an article in Modern Dog Magazine by Elizabeth Pask and Laura Scott, are the omega-3 fatty acids eicosapentaenoic acid and docosahexanoic acid, which Pask and Scott's article says appear prevent the growth and development of some tumors. Omega-3s may also help prevent your dog from suffering cancer cachexia, which is the wasting syndrome of weight loss, fatigue, muscle weakness, loss of appetite and impaired immune function. Conversely, omega-6 fatty acids, the "unsaturateds," have been shown to stimulate tumor development.
Of course fish is the primary source of omega-3s, but fish that come from cold waters are your best bet. Wild Alaskan salmon, Arctic char, Atlantic mackerel, sardines, sablefish or black cod, anchovies, oysters, rainbow trout, albacore tuna, mussels, and Pacific halibut are all high in omega-3s and are environmentally friendly choices. However, of note: Because many fish come from waters polluted with chemicals, especially mercury, be sure to buy the best fish possible. Omega-3s are also found in flaxseed and borage oils.
Fish Oil Supplements
While supplementing your dog's diet with natural sources of fish is the safest way to go -- it's more difficult to over-consume omega-3s found in food -- it can be costly, and sometimes difficult to find appropriate sources, and your dog may not like or tolerate fish well. Consequently, fish oil supplements that you can buy at any health food store are viable alternatives. However, prolonged use of fish oil supplements can cause vitamin E deficiency, and fish liver oils can cause toxic levels of vitamins A and D if overused, according to the American Cancer Society.
Too Much Fish Oil
Always be careful when giving your dog any kind of supplements, including fish oils. According to Dr. Ken Tudor of the petMD website, dogs fed too much omega-3 could suffer higher blood loss when injured or needing surgery, and they could also have problems with wound healing, especially after surgical procedures. Also, Tudor says the anti-inflammatory response created by fish oils can interfere with a sick dog's need for an inflammatory response to protect the body by fighting off germs and diseases.