Eat Yourself Happy? Mediterranean Diet Link To Less Depression
Eating a Mediterranean-style diet - plenty of olive oil, fruits, nuts, vegetables, and fish - may guard against depression, a new study suggests.
What do we know already?
The Mediterranean-style diet has long been linked to a lower risk of heart and circulation problems. The diet, based on the style of eating in southern European countries such as Spain and Greece, is characterised by plenty of olive oil, more fish than meat, a low intake of dairy products, and lots of vegetables and fruit. It also includes alcohol (usually red wine) in moderation.
Researchers aren't quite sure why the diet is linked to health benefits, but one reason is thought to be the low levels of saturated fats it contains (of the type found in butter, cheese, and red meat), and higher levels of monounsaturated fatty acids (found in olive oil), and of certain polyunsaturated fatty acids found in fish.
We also know that Mediterranean countries have lower rates of depression and suicide than northern Europe. This study considered whether the diet typical of the Mediterranean region might be one reason for this.
The researchers recruited 10,000 Spanish graduates, who filled in a food questionnaire at the start of the study and were then followed up on a regular basis.
What does the new study say?
People whose diets were more strongly associated with the Mediterranean diet were less likely to be diagnosed with depression during the four and a half years they were followed up. They had about one third of the risk of those who ate a diet least like the Mediterranean diet.
The researchers say that how much fruit, nuts, and legumes (such as lentils and beans), as well as the types of fats or oils they ate, were strongly linked to a lower risk of depression. They think that the fatty acids found in olive oil may be one factor in lower rates of depression, although they conclude that the overall effect of the diet may be more important than singling out individual foods.
How reliable are the findings?
This was a big, well-conducted study. But studies like this can't prove that one thing caused another: they can only show a link between them.
We know that regular exercise is likely to protect against depression. In the study, people who stuck closest to the Mediterranean diet were also more likely to exercise. The researchers took this into account when they analysed the figures. But there may have been other factors they didn't take into account.
For example, it's possible that people in the study who ate a Mediterranean diet were more likely to live in the south of Spain, where the weather is sunnier and warmer than in central and northern Spain. And Mediterranean-diet foods, such as fish, fresh vegetables, and fruit, may be cheaper and more readily available in the south of the country. It's also possible that the different climate might explain some of the difference in depression. But the researchers didn't consider where people lived in their analysis.
Where does the study come from?
The study was done by researchers from a number of universities in Spain. It was published in the Archives of General Psychiatry, which is owned by the American Medical Association. The study was funded by grants from the Spanish government.
What does this mean for me?
We already know a Mediterranean-style diet can be good for your heart. This study suggests it might be good for your state of mind, too.
From:
Sanchez-Villegas A, Delgado-Rodriguez M, Alonso A, et al. Association of the Mediterranean Dietary Pattern With the Incidence of Depression. Archives of General Psychiatry. 2009;66:1090-1098.
