A Mediterranean-style diet, already thought to protect against diseases like cancer, is now also associated with reducing the risk of depression, according to a Spanish study.

Researchers found that depression was more than 30% less likely to develop in people who followed a diet high in vegetables, fruit, nuts and whole grains, and low in red meat.

Study Details

The research, published in the Archives of General Psychiatry, studied 10,094 healthy subjects who completed an initial questionnaire between 1999 and 2005. Participants reported their dietary intake on a food frequency questionnaire, and the researchers calculated their adherence to the Mediterranean diet, by inclusion of the following components:

• high ratio of monounsaturated fatty acids to saturated fatty acids;
• moderate intake of dairy products;
• low intake of meat;
• high intake of legumes, fruit and nuts, cereals, vegetables and fish.

After a follow-up halfway through the study, 480 new cases of depression were identified. Individuals who followed the Mediterranean diet most closely had a greater than 30 percent reduction in the risk of depression than whose who had the lowest Mediterranean diet scores. The association did not change when the results were adjusted for other markers of a healthy lifestyle, including marital status.

"The specific mechanisms by which a better adherence to the Mediterranean dietary pattern could help to prevent the occurrence of depression are not well known," the authors wrote. Components of the diet may improve blood vessel function, fight inflammation, reduce risk for heart disease and repair oxygen-related cell damage, all of which may decrease the chances of developing depression.

"However, the role of the overall dietary pattern may be more important than the effect of single components. It is plausible that the synergistic combination of a sufficient provision of omega-three fatty acids together with other natural unsaturated fatty acids and antioxidants from olive oil and nuts, flavonoids and other phytochemicals from fruit and other plant foods and large amounts of natural folates and other B vitamins in the overall Mediterranean dietary pattern may exert a fair degree of protection against depression," the authors wrote.

Research Paper Details:

Sanchez-Villegas A, Delgado-Rodriguez M, Alonso A, et al. Association of the Mediterranean Dietary Pattern With the Incidence of Depression: The Seguimiento Universidad de Navarra/University of Navarra Follow-up (SUN) Cohort. Arch Gen Psychiatry, 2009; 66 (10): 1090-1098.