Researchers from the University of Las Palmas and University of Navarra reported in the Journal of American Medical Association (JAMA) that those who eat the Mediterranean diet (plenty of vegetables, fruits and cereals, little red meat) may have less likelihood of developing depression.
The study involved 10,094 healthy adults over a period of 4 years who completed questionnaires which showed that participants who strongly adhere to MDP (Mediterranean Dietary Pattern) were 30% less likely to develop depression. While admitting that further studies are needed, Dr. Cecila D'Felice, a clinical psychologist claimed that there is increasing evidences of the importance of diet in treating depression, with a diet high in olive oil enhancing the amount of serotonin, which is how most anti-depression works (increase serotonin).
SerotoninSerotonin is a monoamine neurotransmitter found extensively in the gastrointestinal tract of animals, some synthesized in serotonegic neurons, found also in fungi and plants including fruits and vegetables.
Source: Wikipedia: Serotonin