The study, led by Felice Jacka, Ph.D. , a NARSAD 2010 Young Investigator at Deakin University in Australia, is the first randomized, controlled trial to evaluate the effects of a healthy diet on the symptoms of depression.
The trial, which the researchers called Supporting the Modification of Lifestyle In Lowered Emotional States (SMILES), involved 67 participants with moderate to severe depression, most of whom were already being treated with psychotherapy, medications, or both
Among those not allowed to participate in the trial were people who had failed antidepressant therapy two or more times
Those in the dietary intervention group met regularly with a dietician and were encouraged to follow a diet made up mostly of fruits, vegetables, whole grains, legumes, lean red meats, fish, low-fat dairy products, eggs, nuts, and olive oil, while reducing their intake of fried foods, processed meats, and sweets and limiting alcohol consumption. The diet was not designed for weight loss, and there were no restrictions on how much participants could eat.
After 12 weeks, depression symptoms had declined significantly more in the group that had followed the improved diet. About one-third of the group following the Mediterranean diet had achieved remission, whereas only 8 percent of those who received only social support reached remission.