Just what are these omega-3s that the news and food product labels are full of? Omega 3s are essential fatty acids, which means our bodies need them but cannot make them so we have to get them from our diet. There are three different omega-3s: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA exists in leafy greens and plant-based oils (especially flaxseed, olive, soy, and canola), as well as walnuts and soybeans. EPA and DHA are found only in microscopic ocean algae and the fish that eat them, particularly fatty fish like salmon, mackerel, anchovies, halibut, herring, striped sea bass, and tuna (albacore).
If we only receive ALA from plant sources, our body can manufacture EPA and DHA from the ALA, but the process is not efficient, and can be further disrupted by the intake of another group of essential fatty acids called omega-6s, which are often present in large amounts in plant-based oils. In Western diets, people consume roughly 10 times more omega-6 fatty acids than omega-3 fatty acids. This is in part why the American Heart Association has recommended specific doses of EPA and DHA.
Extensive research has shown that the intake of EPA and DHA has profound health benefits. The most conclusive scientific evidence shows that DHA and EPA in the form of dietary fish or fish oil supplements lowers triglycerides, reduces the risk of death, heart attack, dangerous abnormal heart rhythms, and strokes in people with known cardiovascular disease, slows the buildup of atherosclerotic plaques ("hardening of the arteries"), and lowers blood pressure slightly.
Multiple studies show arthritis patients see improvements in morning stiffness and joint tenderness with the regular intake of fish oil supplements. Several large studies report that dietary omega-3 fatty acids or fish oil may reduce the risk of developing breast, colon, or prostate cancer. Preliminary studies indicate taking fish oil may reduce the growth of colon cancer cells. There is some evidence supporting the use of omega-3 fatty acids in treating depression, including childhood depression, schizophrenia, and bipolar disease. Many other benefits appear linked to EPA and DHA, and are being investigated.
So what are the drawbacks? In very large doses omega-3s may cause increased bleeding, but this is at levels high above the 3 grams/day considered safe. Some worry about eating fish itself or fish oil supplements because of the risk of contamination. The National Institute of Health (NIH) suggests oil supplements are usually safe because heavy metals selectively bind with protein in the fish flesh rather than accumulate in the oil. An independent test in 2006 of 44 fish oils on the US market found that all of the products passed safety standards for potential contaminants. For healthy individuals, NIH and the American Heart Association consider two servings of fatty fish a week safe and desirable.
So along with your fruits and veggies, consider increasing your omega-3 intake, and particularly EPA and DHA. Consult your doctor before taking omega-3s to treat any disease. And look for more on ratios of omega-3s to omega-6s in a future issue.
- Rebecca Taggart
Rebecca Taggart is a San Francisco yoga instructor.