Staying Sharp: You (and Your Brain) are What You Eat

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We know that what you eat, and don't eat, can affect your health. But is it possible, as the White Rabbit advised Alice, to "feed your head"? Is there such a thing as brain food? I'm convinced there is. The evidence for some foods, such as fish, is stronger than for others, like turmeric and brightly colored vegetables. But none of those foods is bad for you, and they certainly won't make you any less smart.

The reason fish is so good for the brain is the so-called omega-3 fatty acids it contains. Oily fish, like salmon, sardines, mackerel, herring, bluefish and black cod, are the best sources of those special fats. One of the omega-3s—DHA—is the main constituent of cell membranes in the brain, and a deficiency of it can weaken the brain's architecture and leave it vulnerable to disease.

Diets associated with longevity and good health, like the Mediterranean and traditional Japanese diets, are high in omega-3 fatty acids from fish. The North American diet is not. I have long recommended that people in the U.S. eat more fish—at least two servings a week—but I have been concerned lately about reports of increasing levels of mercury, PCBS and other contaminants in certain fish species. In my diet I stick to sardines, herring, Alaskan black cod and Alaskan sockeye salmon. All sockeye (red) salmon are wild—fish farmers haven't yet been able to domesticate them—and since those fish are less carnivorous than other types of salmon, they have lower levels of the environmental contaminants that accumulate as you work your way up the food chain. Canned sockeye, available in most supermarkets, is a perfectly good source of omega-3s.

But for some people it may be easier and safer to rely on fish-oil supplements. The best are distilled and certified to be free of mercury and other toxins. Some are flavored, and some even taste good—or at least a lot better than the cod-liver oil I was forced to take as a kid. One product I recommend is Antarctic krill oil, made from the tiny crustaceans that abound in southern seas and are consumed in great quantities by whales and other marine mammals. Krill oil is red from carotenoid pigments, which have high antioxidant activity, and it doesn't cause those fishy burps. A good starting dose of fish oil of any kind is 1g a day. Higher doses, up to 10g a day, have been used, with varying results, to treat such diverse conditions as depression, attention deficit disorder, bipolar disorder and even autism.

Vegetarian sources of omega-3 fatty acids, such as walnuts, flax and hemp, are good additions to the diet but not so reliable as fish. They supply a short-chain compound (ALA) that the body must convert to long-chain DHA, and the efficiency of that conversion can vary. Some people don't do it well, and those eating mainstream diets top-heavy in the omega-6 fatty acids found in processed food and prepared meals are at a disadvantage because omega-6s interfere with the conversion of ALA to DHA. For vegetarians and vegans, there is one nonfish source of long-chain omega-3s: supplements made from algae. (Algae is the source of the omega-3s that fish store in their fat)