Studies suggest that populations that eat more fish per capita, such as Japan (147 pounds a year) and Iceland (225 pounds a year), have unexpectedly low rates of seasonal affective disorder.
Omega-3s and postpartum depression
Though studies have yet to confirm it, one promising use of omega-3s may be the treatment of postpartum depression. Evidence shows that women who develop postpartum depression tend to have an omega-3 deficiency, and because pharmaceutical antidepressants can be harmful to the fetus and child (through breast-feeding), physicians are hopeful that omega-3s will prove to be an effective preventive treatment during pregnancy.
The best way to get omega-3s is directly from the source (foods such as salmon, halibut, and walnuts), but fish-oil- and flaxseed-oil-based supplements are also available in both capsule and liquid form. Experts recommend taking anywhere from 0.5 to 2 grams a day, although the FDA warns that the daily intake of omega-3 fatty acids from all sources should not exceed 3 grams.