Higher consumption of fruit and vegetables has been associated with a lower risk of various chronic diseases including coronary heart disease, obesity, and certain cancers. Recently, fruit and vegetable intake has also been linked with mental health, including depression. This systematic review aimed to evaluate the association between fruit and vegetable intake and depressive symptoms in young people and adults aged 15-45. The systematic review focused on peer-reviewed cohort studies published from 1 January 2000 to 31 August 2020 using searches of six electronic databases. The exposure was fruit and vegetable consumption analysed both separately and/or together, and the outcome was depression or depressive symptoms. Data from eligible studies were extracted according to predefined criteria and the studies were appraised using the Newcastle-Ottawa Scale (NOS) for Cohort Studies to evaluate for study quality and risk of bias. To evaluate the association between fruit and vegetable consumption and depressive symptoms, a narrative synthesis was conducted. Of 9667 potentially relevant studies that were screened for title and abstracts, 144 full text studies were evaluated, and 12 studies from seven countries were deemed eligible and included in the qualitative synthesis. Using the NOS framework one study was categorised as ‘very good’ quality, ten studies were ‘good’ quality, and two studies were ‘moderate’ quality. With respect to combined fruit and vegetable consumption, two studies demonstrated an inverse association with depression. When the effects of fruit and vegetable on depression were analysed separately, five studies showed significant associations in fruit consumption, and two studies showed significant associations in vegetable consumption. Four studies showed no association between combined fruit and vegetable consumption and depression, one study showed no association between fruit consumption and depression, and two studies showed no association between vegetable consumption and depression. Despite some contradictory results in the studies included in this review, the evidence seems to be building that a possible association exists, and this may have implications for addressing the burden of mental illness in young people and adults aged 15-45 years. Well-designed prospective cohort studies are needed to provide more robust evidence on the diet-depression relationship.
Fruit and vegetable intake and the risk of overall cancer in Japanese: A pooled analysis of population-based cohort studies