Research has shown that depressed people often lack DHA (an omega-3 fatty acid). Peris points to a 2002 study featured in the Archives of General Psychiatry where participants took just a gram of fish oil each day and noticed a 50 percent decrease in symptoms such as anxiety, sleep disorders, unexplained feelings of sadness, suicidal thoughts and decreased sex drive.

“DHA is a very potent anti-inflammatory fat,” adds Kleiner. “It shuts down inflammation in the brain and shuts down inflammation that is about to occur.”

You should eat about 600 to 1,000 milligrams of DHA and EPA per day. Incorporate oily fishes, like salmon, sardines, herring and mackerel, into your diet. You can also find lower doses of these two marine oils in fortified eggs and milk.