A Systematic Review and Meta-analysis of the Effectiveness of Dietary Interventions to Enhance Mental Wellbeing in Emerging Adulthood

Mental well-being in emerging adulthood (18-29y) can come under severe strain. A healthy diet may support a smooth transition and promote high mental well-being among emerging adults. Several systematic reviews have confirmed that a healthy diet can increase mental health in a general adult population, but so far, no systematic review or meta-analysis has summarized experimental evidence of dietary interventions on mental wellbeing. This study conducted a systematic review and meta-analysis of experimental studies into the effects of dietary interventions on mental wellbeing in emerging adults. Nineteen studies were included in the systematic review, of which thirteen in the meta-analysis. The meta-analysis showed a small but significant effect (g = 0.296, 95% CI 0.110-0.481, p = .002). Review findings show that certain dietary interventions have consistent positive effects on some but not all wellbeing indicators (taking breakfast, Mediterranean diet) whereas others show mixed effects on mental wellbeing (fruit and vegetable consumption). Chocolate consumption showed mixed to very short-lived effects (3 min.) on wellbeing. In sum, a Mediterranean diet and its components (cereal and protein breakfast, fruit and vegetables) may promote mental wellbeing among emerging adults. More experimental studies with larger sample sizes are needed to allow moderator analyses to further understand differences in effects between types of dietary interventions and types of wellbeing outcomes.Trial Registration This systematic review was registered in the PROSPERO International Prospective Register of Systematic Reviews under the number CRD42020165113.