Longitudinal associations between fruit and vegetable intakes and depressive symptoms in middle-aged and older adults from four international twin cohorts

Beneficial associations between higher fruit and vegetable intakes and risk of depression appear to exist but few studies have focused on adults aged 45 + years and the potential that associations are due to residual confounding has not been tested. This longitudinal study of twins (n = 3483, age 45-90 years) from Australia, Denmark, Sweden and USA, assessed the associations between baseline fruit/vegetable intake and depressive symptoms over 5-11 years using linear mixed effects models. Intakes from food frequency questionnaires were trichotomized. Depressive symptoms were assessed using validated measures. The co-twin method was used to examine familial confounding. Compared with low intakes, both high fruit and high vegetable intakes were associated with lower depressive symptoms (fruit: β -.007 [95%CI - .014, < - .001], p = .040; vegetables: β - .006 [95%CI -.011, -.002], p = .002); whereas only moderate vegetable intakes, were associated with lower depressive symptoms (vegetables: β - .005 [95%CI - .009, - .001], p = .014). No familial confounding was found for vegetables, while the results for fruit were inconclusive, likely due to smaller sample size and the marginal significance of the main result. Higher fruit and vegetable intakes may protect against depressive symptoms, presenting another argument for increasing intakes in adults aged 45 + years.