If you eat a diet with lots of olive oil, you can reduce the risk of becoming depressed. A spanish study investigated 12 049 people, who at the start of the study were not depressed. They were given a questionnaire about their eating habits. Then, six years later, the same people were checked to see which of them had had a depression. The researches found that those who eat more than 20 gram (=0.7 ounces) of olive oil per day had a 30 % reduced risk of becoming depressed. The study also found that trans fats (common in fast food and pies) increased the risk of becoming depressed. Those who at more than 1.5 grams (0.05 ounces) had a 48 % higher risk of becoming depressed.

The researchers believe that this is caused by good and bad types of cholesterols in the blood. Bad types of cholesterols can cause many small inflammations, which reduces the capability of the nerves to transfer serotonin.

Mediterranean food, containing lots of olive oil, fruits and vegetables, reduces the risk of depression.