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.