The association between dietary diversity and depressive symptoms among adult population in rural Western Kenya

IntroductionLow dietary diversity has been identified as a predictor of depression outcomes in high-income countries, while evidence is scarce from low-income settings where poor nutrition and depression often co-occur. In this study, we estimate the relationship between dietary diversity and depression among adults in rural western Kenya. MethodWe conducted a cross-sectional analysis of 311 participants enrolled in the Bridging Income Generation through Group Integrated Care program. We assessed depressive symptoms using the 20-item Centre for Epidemiologic Studies for Depression Scale (CES-D), and measured dietary diversity as the number of five food groups consumed in previous 24-hours using a validated dietary diversity scale. We used linear regression to estimate the association between high dietary diversity (consumption of all the five food groups) and continuous depression scores, adjusting for key covariates. We tested for effect measure modification by wealth status. We conducted a secondary analysis using quantile regression to explore variation across depression scores distributions. ResultsHigher dietary diversity was associated with fewer depressive symptoms [adjusted {beta} (95% CI): -3.49 (-6.62, -0.38)]. The association was stronger among individuals with low wealth backgrounds [adjusted {beta} (95% CI): -6.00 (-10.46, -1.42)] relative to those with high wealth backgrounds [adjusted {beta} (95% CI): -0.53 (-4.76, 3.68); Wald p-value for interaction term =0.0003]. The effect sizes for the association were larger at higher quantiles, notably at 75th [adjusted {beta} (95% CI): -4.00 (-10.13, 2.13)] and 90th [adjusted {beta} (95% CI): -1.59 (-7.43, 4.25)] compared to those at lower quantiles for 10th [adjusted {beta} (95% CI): -0.59 (-2.46, 1.28) and 25th [adjusted {beta} (95% CI): -0.82 (-4.14, 2.50), though wide confidence intervals limited the precision of effect estimates. ConclusionIn rural western Kenya, higher dietary diversity was associated with lower depression symptoms, particularly among participants from lower wealth backgrounds, and particularly among those with scores consistent with more severe depression symptoms. These findings suggest that improving dietary diversity may offer mental health benefit to the most socioeconomically disadvantaged individuals and could be a promising strategy to reduce depression in resource poor settings. Future work could leverage longitudinal and experimental studies for improved inference and should investigate mechanisms through which dietary diversity may influence depression.