Flavonoids are phytonutrients (plant nutrients) found in tea, chocolate, red wine and many fruits and vegetables. They are already known to offer protective cardiovascular health effects and other health benefits, however the effect of flavonoid intake on depression has been unclear up to this point. Researchers from Harvard published an article in the American Journal of Clinical Nutrition analyzing data from the Nurses’ Health Study and the Nurses’ Health Study II, looking at potential links between flavonoid intake and depression.

The Nurses’ Health Study and Nurses’ Health Study II included 82,643 women without a previous history of depression. Over a period of 10 years of follow-up, a total of 10,752 incidents of depression were found. Analysis of flavonoid intake and depression frequency revealed that the highest quintile of total flavonoid, polymer, and proanthocyanidin intake was associated with a 9-12% decreased risk of depression. Lower intakes were associated with a reverse linear, but still significant decrease in depression risk. In women over 65 years, the results had even stronger statistical relevance and did so with almost all classes of flavonoids.

Flavonoid intake is associated with lower incidences of depression, with particularly strong links at the highest intakes and in older women. Not only does this study offer evidence that flavonoid intake may decrease the likelihood of depression, but it provides further evidence about the overall health benefits of flavonoid intake.