Abstract
BACKGROUND: Anxiety and depression are widespread mental health disorders with substantial global influence. dietary exposures have been proposed as modifiable risk factors of these diseases, but their causal relationships remain uncertain. This study aimed to elucidate the causal effects of specific dietary exposures on the risks of anxiety and depression using Mendelian randomisation (MR). METHODS: Two-sample MR analysis was performed using summary-level data from large-scale genome-wide association studies of European populations. Nineteen dietary exposures, including beef, cereals, tea, non-oily fish and unsalted peanuts, were analysed. Causal estimates were obtained using the inverse variance weighted (IVW) method, MR-Egger regression and weighted median approach. Sensitivity analyses were conducted to assess heterogeneity and horizontal pleiotropy. RESULTS: High consumption of beef (odds ratio [OR] = 0.95, 95% confidence interval [CI]: 0.9182-0.9854, p < 0.01) and cereals (OR = 0.99, 95% CI: 0.9723-0.9982, p = 0.026) was associated with a reduced risk of depression, Whereas high tea consumption (OR = 1.01, 95% CI: 1.0009-1.0176, adjusted p = 0.029) was linked to an increased risk. Regarding anxiety disorders, non-oily fish intake (OR = 1.01, 95% CI: 1.0024-1.0121, p < 0.01) was positively associated with this risk, whereas unsalted peanuts (OR = 0.98, 95% CI: 0.9527-0.9986, p = 0.038) showed a protective effect. CONCLUSIONS: This MR study provides genetic evidence supporting the role of specific dietary exposures in influencing the risks of anxiety and depression. The findings highlight the potential of targeted dietary interventions in the prevention and management of mental health disorders.