The omega-3 fatty acid in some fish may be a "brain food" that helps ward off depression because it increases gray matter in three areas that tend to be smaller in people who have serious depression, a study suggests today. The increase could help explain why past studies have found that the omega-3 acid DHA reduces symptoms of depression. The richest sources of DHA are fatty fish and fish-oil capsules. Researchers gave magnetic resonance imaging tests to 55 adults. Participants also reported everything they ate for 24 hours on two randomly selected days, says study leader Sarah Conklin, a neuroscientist at University of Pittsburgh Medical School. She'll report her findings at the American Psychosomatic Society meeting in Budapest. The more DHA a person consumed, the more gray matter there was in three areas of the brain linked to mood: the amygdala, the hippocampus and the cingulate, Conklin says. Seriously depressed people tend to have less gray matter in these areas, she says. "That doesn't mean omega-3 is a panacea for depression," she says. "Many other things influence risk, such as genetics, environment, drug use and alcohol."