What cancer-related uses of fish oil have the best scientific evidence behind them? Dr. Block presented on this topic at the 10th International Society for Integrative Oncology in Vancouver, British Columbia on Sunday, October 20.
Laboratory studies of fish oil show that it has many effects on cancer, from modifying blood viscosity to modulating treatment resistance. It has beneficial effects on the important processes of apoptosis and angiogenesis. EPA and DHA, the major omega-3 fatty acids in fish oil, diminish inflammation, a critical driver of many cancer processes.
Besides lab studies, several important recent observational and clinical studies have shown the benefits of fish oil on different cancers. Breast cancer patients whose diets included the most EPA and DHA had 28% less risk of recurrence or metastasis, and 41% lower risk of mortality than those with the least. A randomized study of fish oil taken during chemotherapy for lung cancer found that patients had improved rates of tumor shrinkage, less weight loss and better retention of muscle mass. Prostate cancer patients who were given fish oil and a low fat diet before surgical removal of the prostate were found to have tumors with lower rates of cancer cell proliferation than those who ate typical Western diets. Fish oil also helped to maintain weight and immune function in gastrointestinal cancer patients who were receiving chemotherapy.
There are very few side effects from taking fish oil. Gastrointestinal side effects, such as belching or stomach upset, can be minimized by taking enterically coated fish oil capsules. We recommend fish oil that contains added vitamin E to reduce oxidation, which fish oil is prone to. Finally, fish oil has blood thinning effects and should be used cautiously with medications that thin the blood, and during times when blood platelets are low due to chemotherapy. If your doctor tells you, for instance, that you should not take aspirin due to low platelet counts, it is prudent to ask her/him if you should also stop fish oil supplements.
Dr. Block also discussed the study on omega-3 blood levels of prostate cancer patients by Brasky and colleagues that was discussed in this blog a few weeks ago, concluding that the results of this study did not offer any conclusive evidence of harm from taking fish oil. With the basis of randomized trials and observational studies of solid design showing benefit from taking fish oil, we continue to feel that this source of essential omega-3 fats is a healthful supplement for cancer patients.
For more information on The Block Center for Integrative Cancer Treatment, call (847) 230-9107 or visit BlockMD.com.