Br J Nutr. 2020 Mar 10:1-22. Epub 2020 Mar 10. PMID: 32151287
Effect of 4 weeks daily wild blueberry supplementation on symptoms of depression in adolescents.
Adolescence is an important period for cognitive maturation and emotional regulation and this age group is particularly vulnerable to developing depression. Diets rich in fruits and vegetables have been associated with decreased risk of developing depressive disorders across the lifespan, an association that may be due to the high flavonoid content of these foods. Previously we have shown increases in transient positive affect in both children and young adults two hours after administration of a wild blueberry intervention. Here, using a randomized double-blind, placebo-controlled trial, we investigated the effects of four weeks, daily wild blueberry supplementation (containing ~253mg anthocyanins) on transient and chronic mood in adolescents. Healthy 12-17-year old (N = 64, 35 females) were recruited and randomly assigned to receive either a wild blueberry or matched placebo supplementation. Depression and anxiety symptoms were assessed before and after the intervention period using the Mood and Feeling Questionnaire and Revised Child Anxiety and Depression Scale. Transient affect was assessed before, two weeks, and at four weeks using Positive and Negative Affects. Following the intervention period there were significantly fewer self-reported depression symptoms in participants who were supplemented with the wild blueberry intervention compared to those who received the matched placebo (p=0.02, 95% CI -6.71 to -5.35). There was no between group effect on anxiety symptoms or on transient affect. Further investigation is required to identify specific mechanisms that link flavonoids consumption and mood. If replicated, the observed effects of wild blueberry supplementation may be a potential prevention strategy for adolescent depression and may have benefits for public mental health.