Associations of a healthy dietary pattern, foods, and nutrients with the incidence of high depressive symptoms in two large cohort studies in the Netherlands

Background: We studied the association of a healthy dietary pattern, different foods, and nutrients with the incidence of high depressive symptoms over 6-11 years in two population-based cohorts in the Netherlands. Methods: We included data from the multi-ethnic Healthy Life in an Urban Setting study (HELIUS, N=2556, aged 18-71 y) and the Longitudinal Aging Study Amsterdam (LASA, N=800, aged 55-91 y). Dietary intake was assessed using the HELIUS food-frequency questionnaire. Depressive symptoms were based on questionnaires with established cut-offs: PHQ-9 ≥ 10 in HELIUS and CES-D ≥ 16 in LASA. We analysed the data according to the guidelines of the Global burden of disease Lifestyle And mental Disorder Taskforce. Cohort-specific log-linear models with robust variance estimation were conducted in the full sample and stratified by sex. In the main models we used the residual method to account for energy intake and adjusted for baseline confounders.Results: In HELIUS, we observed no associations in the total sample. In men, a higher processed meat intake (IRR=1.016, 95% CI=[1.004, 1.028]), and a lower fibre intake (IRR=0.954, 95% CI=[0.914-0.995]) were associated with a higher incidence of high depressive symptoms. In LASA, a higher polyunsaturated fatty acid intake was associated with a lower incidence of high depressive symptoms in the total sample (IRR=0.947, 95% CI=[0.907, 0.989]). No associations were found in sex-stratified analyses.Conclusion: In this prospective study of two population-based samples, we found limited evidence for an association between diet and the incidence of high depressive symptoms.