Eating Your Way to Mental Health
Evidence Is Mounting That Fatty Fish Can Treat Depression

Feeling depressed? Ask not what your parents did or didn’t do when you were a child. Ask yourself what you had for dinner last night, and the night before, and the night before that.

For half a dozen years now, the evidence has been growing that omega-3 fatty acids, the kind found in fatty fish like salmon, sardines, and tuna, can help prevent and treat depression.

Rich in EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), these are among the “good” oils that have long been known to reduce the risk of heart attacks and strokes. They are also the oils that, in recent decades, in tandem with rising depression rates, Americans have not been getting enough of. Omega-3s combat auto-immune diseases like rheumatoid arthritis, reduce cardiac arrhythmias, and are crucial to the development of the spinal cord, brain, and retina in infants and to healthy brain functioning in adults as well.

The case for linking low omega-3 levels to depression is strong, though not yet a slamdunk. But there is little risk – and significant benefit – to following the American Heart Association recommendation to eat fish at least twice a week and, if you already have heart disease, taking at least 1 gram a day of supplements containing EPA and DHA.

The latest evidence for the role of omega-3 fatty acids and depression came last month, when researchers from McLean Hospital in Belmont, Mass., reported that omega-3 fatty acids, plus uridine, another substance found commonly in meat and other protein-rich foods, prevented depression in rats just as well as antidepressant drugs. The effect of uridine was immediate, said Bill Carlezon, director of the behavioral genetics lab at McLean. It took 30 days for omega-3 to kick in. But combining the two made omega-3 effective three times faster.

“There is something to this story,” said Dr. Andrew Leuchter, vice chair of psychiatry at the Neuropsychiatric Institute at UCLA. “I have seen enough patients who treat themselves with omega-3 fatty acids to think these substances may have, at least in some individuals, potent effects on mood.”

No one knows exactly why omega-3s might protect against depression, but theories abound. One is that depression may, in part, be an inflammatory problem, which omega-3s can damp down, said Dr. Andrew Stoll, director of psychopharmacology at McLean. Another is that the oils keep cell membranes more fluid, making it easier for receptors to respond to neurotransmitters like serotonin, which is often deficient in depression. Another is that omega-3s may boost levels of serotonin.

Whatever the underlying mechanism, “the epidemiological evidence is huge,” Dr. Stoll said, that omega-3s can protect against depression.