Since the lifetime prevalence of mental disorders is lower in Mediterranean countries than in Northern European countries, a study was conducted to see if diet plays a role as a protective factor.
We have covered the Mediterranean diet previously, in the article Take It Or Leave It? The Truth About 8 Mediterranean Diet Staples, which we recommend reading to get up to speed about the particulars of this diet.
The report was published in the October issue of Archives of General Psychiatry. Over 10,000 Spanish people participated in this study. Participants had to fill out a survey detailing their dietary intake. Researchers then translated those details into a level of adherence to the Mediterranean diet using a system of nine components. For example, one such component is maintaining a high ratio of monounsaturated fatty acids to saturated fatty acids in the diet.
After a median (midpoint) of 4.4 years of follow-up, 480 new cases of depression were identified, including 156 in men and 324 in women. 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 and use of seatbelts.
The scale of the study seems to clearly show some correlation between following the Mediterranean diet and better mental health. However, as long time readers are undoubtedly aware, correlation is not causation.
“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 write. 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 write.
There may be a combination of factors at play here. Perhaps living in Spain is less depressing than living in Northern Europe regardless of diet. We need scientists to unravel the specific mechanisms which are responsible for these results. Until then, we can only speculate.
Vitamin D is called the “sunshine vitamin” for a reason, and people in Northern Europe may simply not be getting enough.
Dairy is a good source of Vitamin D, but most people do not eat enough dairy to meet their daily requirements without sun exposure. Aside from the fact that eating so much dairy may be unhealthy and counterproductive, 60% of adults cannot digest lactose.
An important component of the Mediterranean diet is fish, and fish are rich in Docosahexaenoic acid (DHA). A recent study determined that feeding infants formula enriched with DHA is worth the cost premium because it can enhance IQ.