Fish oil – found in the fatty tissues of cold-water fish, is a source of the two essential omega-3 fatty acids, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). We all need these to maintain long-term health, to reduce our risks of heart disease and cancer, to decrease excessive inflammation and enhance mood. You should try to get omega-3s by eating at least 3 servings per week of oily fish, such as wild Alaskan salmon, mackerel, sardines, herring, or sablefish. I also recommend taking supplemental fish oil, at least two grams a day.
Fish oil does not help with heartburn or GERD. In fact, because both can be side effects of taking fish oil supplements, it is important to take them with food. Other possible side effects include belching, bad breath, nausea, loose stools, rashes and nosebleeds. These unwanted consequences appear to be rare. A review of 148 studies, including data on some 10,000 participants who were taking omega-3 supplements, found that more than half of the studies reported no adverse effects. The others found that those side effects that did occur were minor, usually digestive in nature and occurred among fewer than seven percent of the participants. In most cases, reducing the dose or discontinuing the supplements solved the problems.
Fish oil can help treat constipation, probably because it helps lubricate the intestines.
Individuals who take anticoagulant drugs or have bleeding problems should be cautious about fish oil supplements, since high doses of omega-3s can affect blood clotting. Very high intakes of fish oil/omega-3 fatty acids (termed “Eskimo amounts” by the National Institutes of Health, in reference to diets that consist almost exclusively of fish) have been associated with nosebleed and blood in the urine and may increase the risk of hemorrhagic stroke.
When choosing an omega-3 supplement, look for one derived from molecularly distilled fish oils to help assure it is free of mercury and other contaminants.
Andrew Weil, M.D.
- Wang et al “Effects of Omega‐3 Fatty Acids on Cardiovascular Disease: Summary.” Agency for Health Care Research and Quality, March 2004, https://www.ncbi.nlm.nih.gov/books/NBK11854/