People who followed the Mediterranean diet, which is rich in fruits, vegetables, whole grains, fish and nuts, were less likely to develop depression in a Spanish study (2009 Archives of General Psychiatry).
“We are speaking of a relative reduction in risk of 42 percent to 51 percent,” said study co-author Dr. Miguel A. Martinez-Gonzalez, chair of preventive medicine at the University of Navarra. “This is a strong association.”
The Mediterranean diet usually often recommended to reduce the risk of heart attack, stroke and other cardiovascular problems. This study is one of only a few to look at the effect of tis diet on mental functioning.
More than 10,000 healthy adults who filled out questionnaires over a six-year period were followed. All were free of depression at the start of the trial. Their diet was measured through nin components: low intake of meat, moderate intake of alcohol and dairy products, and high intake of fruits, nuts, cereals, vegetables and fish.
After about four and a half years, the overall incidence of depression for those who most followed the diet was 30 percent lower than for those who most ignored the dietary rules. Even lower rates of depression were associated with intake of specific elements of the Mediterranean diet, such as fruits, vegetables and olive oil.
Lead author Martinez-Gonzales explained that this diet improves the function of the endothelium, the delicate inner lining of blood vessels. The endothelium is involved in the production of neurotrophic factor (BDNF), responsible for the growth and function of nerve cells. “Dysfunction of BDNF is thought to be responsible for some depression cases.” Olive oil also improves the binding of serotonin to its receptors, a key neurotransmitter in depression. He added, “In fact, Prozac acts by increasing the availability of serotonin in the brain.”
Omega-3 fatty acids, abundant in this diet, are thought to improve function of the central nervous system. In all, those who follow this diet could be expected to have greater resilience in handling everyday stresses.
HealthDay reports: “It’s not surprising to see these results,” said Dr. David Mischoulon, an associate professor of psychiatry at Harvard Medical School. “They are what we would have expected to see on the basis of previous information. There is a very large body of work in the psychiatric literature saying that components of the Mediterranean diet when looked at separately have such an effect.” Mischoulon agreed that he would not recommend the diet as a treatment for existing depression. “A person in an episode of depression needs more direct and more targeted intervention,” he said.But the study adds one more reason for adopting the Mediterranean diet, Mischoulon said. “If you have a family history of depression and you are concerned about it, a diet like this probably would be a good place to start,” he said.
Click for an explanation of the Mediterranean diet by the American Heart Association.
Sources: Miguel A. Martinez-Gonzalez, MD, PhD, professor and chair, department of preventive medicine, University of Navarra, Pamplona, Spain; David Mischoulon, MD, associate professor, psychiatry, Harvard Medical School, Boston; October 2009 Archives of General Psychiatry; Federal Government’s Source for Women’s Health Information.