Associations between fruit and vegetable consumption and depression symptoms

Depression is a highly recurrent, chronic, and potentially lifelong mental illness. Increasing efforts to develop preventive strategies for depression is a critical investment. The role of diet and particularly higher fruit and vegetable consumption has been of particular interest as a novel approach to reduce the risk of depression. However, the associations between fruit and vegetable consumption and depression symptoms remain largely unexplored in young people and adults. This thesis comprises two studies, a systematic review¹ and a secondary analysis study¹. The first study aimed to systematically review the longitudinal studies of the associations between fruit and vegetable consumption and depression symptoms in young people and adults aged 15-45. The second study examined the differential effects of fruit and vegetables in relation to depression symptoms over a 15-year follow-up in young women from the 1973–78 cohort of the Australian Longitudinal Study on Women’s Health (ALSWH). Findings from the systematic review suggested that a possible association exists between fruit and vegetable consumption and depression symptoms, particularly consuming fruit on a daily basis. The secondary analysis supported the evidence that fruit and vegetable consumption was cross-sectionally associated with lower odds of depression symptoms over 15 years of follow-up. In longitudinal analysis, higher intake of fruit (≥ 4 servings) and vegetable (≥ 5 servings) was consistently associated with lower odds of depressive symptoms, with a 25% lower odds (OR 0.75; 95% CI 0.57, 0.97; p = 0.031) and a 19% lower odds (OR 0.81; 95% CI 0.70, 0.94; p = 0.007) than consuming one serve or less of fruit and vegetable respectively. The collective thesis findings highlight the importance of consuming adequate fruit and vegetables for reducing the risk of depression symptoms. Therefore, increasing fruit and vegetable consumption can be a promising approach for reducing the risk of depression symptoms. Furthermore, policy actions at a national and international level are needed to increase the availability, acceptability and affordability of fruit and vegetables.