Oct. 5, 2009 -- A new study suggests people who follow a traditional Mediterranean diet, rich in foods like vegetables, fruits, nuts, whole grains, olive oil, and fish, may be less likely to develop depression.
Researchers say rates of depression are lower in Mediterranean than northern European countries, and the findings suggest that the food of the Mediterranean diet may an important role in fighting depression.
The study, published in the Archives of General Psychiatry, involved 10,094 healthy Spanish adults. Researchers collected information on the foods they regularly ate and then rated their diets based on adherence to the following components of the Mediterranean diet:
- High ratio of monounsaturated fatty acids (such as those found in olive oil) to saturated fatty acids (found in animal fats like butter and meat).
- Moderate use of alcohol and dairy products.
- Low intake of meat.
- High intake of legumes, fruits, nuts, cereals, vegetables, and fish.
After nearly four and a half years of follow-up, 480 new cases of depression were diagnosed.
The results showed those who most closely followed the Mediterranean diet were more than 30% less likely to develop depression than those who least adhered to the diet.
Researchers say it's unclear exactly how the foods of the Mediterranean diet may fight depression. But individual components of the diet may improve blood vessel function, fight inflammation, reduce the risk of heart disease, and repair oxygen-related cell damage, all of which may affect the risk of developing depression.
"However, the role of the overall dietary pattern may be more important than the effect of single components," write Almudena Sanchez-Villegas, B. Pharm, PhD, of the University of Las Palmas de Gran Canaria in Pamplona, Spain, and colleagues. "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."