Fish Maintain Your Brain

Cod liver oil may be good for you, but it sure tastes awful.
Old-fashioned fish oil, usually in pill form, has regained its popularity as a health supplement now that the benefits of omega-3 fatty acids, found primarily in fish oils, are rapidly being confirmed.

Food manufacturers are jumping into the fray with a range of
products, from salad dressing to waffles that are supplemented with omega-3s. Known primarily for keeping the heart and blood vessels fit, these fats also improve mental health. Previous studies have linked low levels of the fatty acids to higher rates of depression, bipolar disorder and suicide.

Because brain cells are encased in fat, omega-3s help maintain brain cells and keep neurotransmission fluid. Fish oils may be as effective as conventional drugs in alleviating unipolar and bipolar depression, says Andrew Stoll, director of the psychopharmacology research lab at McLean Hospital in Belmont, Massachusetts.

But how much omega-3 fat is enough? The American Heart Association recommends at least two servings of fish per week to get cardiovascular benefits. A three-ounce serving of farmed Atlantic salmon has about 1,500 mg of omega-3 fat. Fish is the recommended source of omega-3s because only marine life contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the two most accessible forms of the fats. Also, adds Alice H. Lichtenstein, vice chair of the American Heart Association's nutrition committee and a professor at Tufts University in Massachusetts, a diet with regular servings of fish will likely cut down on steak, cheese and other sources of unhealthy fats. Walnuts and flaxseed are not adequate substitutes for fish, Lichtenstein says.

The ideal balance of EPA and DHA is hard to pin down, and may be different for different purposes, says Joseph Hibbeln, a psychiatrist who studies diet and behavior at the National Institutes of Health. A good starting point may be the same proportions one gets by eating fish: two to three times as much EPA as DHA. A third form of omega-3s, called alpha-linolenic acid (LNA), found in flax seeds and leafy plants, is useful because the body can convert it into EPA and DHA. But the conversion process is slow, and the same mechanism converts parts of soybean, corn and safflower oils into inflammatory omega-6s, which most Americans already consume in abundance. The production of EPA and DHA could be stymied if your body is already occupied processing omega-6, Hibbeln says.

Several factors control the amount of omega-3 available for use in the body: the amount of EPA and DHA in your diet, how much is converted from LNA and how much omega-6 your body is producing.