This was a study done to see if there was a link between dietary choices and the chance of developing depression. The study included over 4000 participants and followed them for up to 10 years. If you have been following this blog you know a large sample size (using lots of people) and following them for long periods are factors that improve the quality of a research study.

For this study the researchers were able to single out some key components of diet and found links between how frequently the person ate these items and their likelihood of developing depression. For instance they found if someone ate more fruit and vegetables they were less likely to develop depression. Even if they started out with low amounts of fruit and vegetable intake then increased them throughout the study it lowered their chance of developing depression. So it’s never too late to make healthy changes that will impact your life! Fruits and vegetables showed the strongest influence on depression but there was also a decrease in depression associated with increases in fiber, nuts and multivitamin use. The study also showed higher intakes of trans-fats, the hydrogenated oils found in many processed foods, was linked with an increase in developing depression. Also eating more saturated fat than polyunsaturated fat increased the rates of depression.

Since this study was looking at overall diets and not just one or two nutrients, there are several explanations as to why the particular diet factors were found to lower the chance of developing depression. The increases in antioxidants from eating a diet rich in fruits and vegetables have numerous benefits to the body. The antioxidants could protect someone from depression by reducing inflammation in the body. Chronic inflammation is a continual strain on the body which taxes our immune system and wears down our resistance to a number of diseases. This strain can also affect our brain function. This exhausting combination of stress to our body and brain is a recipe to develop depression.

It is also well known that trans fats, the hydrogenated oils found in processed foods have a dangerous effect on our brains. By weight our brain is made up of more fat than nerve cells. This fat surrounds each nerve cell to help protect it and serves as insulation to aid the transmission of nerve impulses. The more fluid this fat is the better it works in the brain. Trans fat is the stiffest and most rigid fat available. It is manufactured this way to be more stable and resist going bad while the “food” sits on the shelf. That’s fine for the food like product but bad for your brain. The most fluid fat, and therefore best for your brain, is from fish oil. That is why so many studies have shown the benefits of fish oil on depression and other health factors.

So to curb depression, and influence many aspects of your health in a positive way eat your fruits and vegetables while avoiding processed foods! See an apple a day really does keep the Doctor away!

Am J Clin Nutr 2013 February, 97(2): 419-427

By Dr Scott Szela