Omega-3 fatty acids
Omega-3 fatty acids are found in fish and algae as well as seeds and nuts. Our cells cannot make omega-3 fatty acids so we must consume them. Omega-3 fatty acids in plants are comprised of alpha-linolenic acids (ALA). Once ingested, we break down ALA into eicosapentoic acid (EPA) and docosahexaenoic acid (DHA). Alternatively, EPA and DHA can be consumed by eating seafood or algae products.
Deficiencies
The optimal blood level of omega-3 is expressed as a percentage of the fatty acids in red blood cell membranes which are EPA and DHA. The optimal level omega-3 fatty acids is approximately 8%. Vegetarians are generally deficient in EPA and DHA because it is difficult for the body to convert sufficient ALA into EPA and DHA. Additionally, anyone who does not regularly eat seafood, seeds and nuts may be deficient. Having sufficient omega-3 fatty acids may be associated with a lower risk of cancer, especially colon and breast cancers.
There are blood tests available, the most well-studied of which is the OmegaQuant® test, which can check blood levels of omega-3 and other types of fatty acids. These tests can be self-ordered or ordered by healthcare practitioners although they may not be covered by insurance.
Outright deficiency of omega-3 deficiency is extremely rare. However, most modern Western diets result in relative deficiency of omega-3 fatty acids compared to omega-6 fatty acids which are found in a wide variety of grains, meats and vegetables. This relative deficiency is linked with inflammatory joint pain, impaired immunity, increased risk of coronary artery disease, and increased risk of muscle wasting (sarcopenia). Relative deficiency of omega-3 can be addressed with diet and/or supplementation.
Role of Omega-3 fatty acids in cancer
Omega-3 supplementation with conventional chemotherapy treatment may improve the anti-cancer effects of the chemotherapy, especially for colorectal cancer, breast cancer and non-small cell lung cancer. Omega-3 fatty acids can also improve tolerance to conventional treatment by reducing joint pain, supporting a balanced mood, lowering the risk of peripheral neuropathy and decreasing the risk of loss of lean muscle.
Type and Dose
Supplemental omega-3 is most commonly in the form of fish oil, with algae oil appropriate for vegetarians. Although fish oil supplements are commonly available, the quality varies considerably. Fish oil can be contaminated with heavy metals. Fish oil products should be tested for heavy metals, especially mercury. Fish oil can become rancid, especially when packaged in clear bottles which allows light to oxidize the fatty acids. Rancid fish oil will have a strong fishy odor.
The dosage of fish oil varies depending upon the indication for its use. Nonetheless, a commonly studied and recommended dose is between 1g – 2g of omega-3 daily (as EPA and DHA). Fish oil supplements should always be taken with food to avoid fishy burps.
Warnings
High doses of fish oil can cause diarrhea, nausea and fishy burps. Fish oil may be discontinued prior to surgery due to concerns about increased bleeding risk. While clinical research has not proven this risk, caution and health provider supervision is best for someone undergoing surgery. Additionally, if you are taking a blood thinner (anti-coagulant), fish oil should be discontinued.
Resources
https://www.mskcc.org/cancer-care/integrative-medicine/herbs/omega-3
