Fish: Good for the Head and the Heart

It's possible that depression and heart disease don't cause each other. They may share one underlying cause, perhaps a common biological pathway such as subchronic inflammation. Or, say Canadian researchers Francois Lespérance, M.D., and Nancy Frasure-Smith, Ph.D., they might both be caused by a dietary shift to inadequate levels of omega-3, a fatty acid essential to the body but not produced by it; it must be supplied by diet, primarily fatty ocean fish. As critical components of every cell membrane, omega-3 fats boost cell function. Whether or not omega-3s are it, almost everyone believes they are a big part of the story—and an essential part of the remedy. They're anti-inflammatory. They act on platelets to reduce blood clotting. They're antiarrhythmic, aiding heart rate variability through parasympathetic channels. "They impact the multiple mechanisms linking heart disease and depression," says Lesperance. And they boost mood. Of two known omega-3s, depression may respond best to EPA (eicosapentaenoic acid). Hearts seem to favor a mixture of EPA and DHA (docosahexaenoic acid).