It is known that diet can have a significant impact on the development and function of the brain and growing evidence suggests links between diet, cognition and mood disorders. Dietary flavonoids are the most common polyphenolic compounds in the diet, they occur naturally in plant foods and are present in substantial amounts in commonly consumed fruits and vegetables. A number of plausible biological mechanisms link intake of flavonoids to both mood disorders such as depression and cognition, including an increase in blood flow to the brain which may lead to nerve cell growth and the formation of new blood vessels and a reduction in neuro-inflammation, an important contributor to depression. In a study of over 80,000 adults, we found that a higher intake of flavonoids from citrus fruits was associated with a 10% lower risk of depression (Chang et al. 2016). Furthermore, flavonoid clinical trials have reported significant benefits to cognition, mainly in the executive function (cognitive control) domain (Macready et al. 2009).

Adolescence is both a period of significant cognitive development and a period of high risk for developing mood disorders; thus it is an ideal time to target preventive interventions. This project will examine a number of commonly consumed flavonoid subclasses in order to assess which flavonoids are most effective for preventing low mood and cognitive dysfunction in children. Different flavonoid sub-classes have shown to differ in both bioactivity and bioavailability and are therefore likely to show differential associations with our outcomes.