Don't be afraid of fish oil

Philip J. Goscienski, M.D.

September 2011

A deficiency of omega-3 fatty acids is among the more serious shortfalls in the American diet. More than half a century ago nutritionists referred to them as essential fats because the body cannot manufacture these nutrients. In a perfect nutritional world we would get them from fish and green leafy vegetables but omega-3 inadequacy is part of a lifestyle that contains very little of each.

Among persons with very low blood levels of omega-3 fats there is a greater likelihood of psychiatric disorders that include attention deficit disorder (ADD), aggressive behavior and depression, including postpartum depression.

A child's developing brain requires large amounts of omega-3 fats in the form of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) from early fetal life until about the age of two. That leaves women of childbearing age with a difficult choice because fish, especially the larger species, sometimes contain high levels of mercury and cancer-causing chemicals. What to do?

Pregnant women can reduce the hazard of mercury from fish by avoiding certain types such as swordfish, shark, king mackerel and tilefish during pregnancy and to limit tuna and sea bass. Not all types of tuna are high in mercury but it's simply easier to avoid it all for a few months. Smaller fish such as salmon and sardines are OK. Fish oil from reputable sources is a good alternative.

Another fear is the risk of bleeding from high levels of omega-3 fats. Persons with heart disease such as atrial fibrillation may be taking Coumadin or other blood-thinners. Should they avoid fish and fish oil? Studies show that bleeding will not occur, even in patients who are taking Coumadin or aspirin, at high intakes of 3 to 5 grams of fish oil per day (or more than about 8 ounces of fish such as salmon).

A seeming solution is to obtain essential fats from flaxseed and other plant sources but it doesn't work in practice. High doses of flax can interfere with some medications such as pain relievers and cholesterol-lowering agents. Further, the conversion of the fatty acids in plant foods to DHA and EPA is not very efficient.

There is no way to avoid all toxic elements in our food supply. The bottom line: the benefits of fish and fish oil far outweigh the risk of mercury toxicity and bleeding, especially when persons most at risk follow simple guidelines to reduce those hazards.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at