What role does salt play in depression and anxiety? A prospective cohort study

Background: Despite the numerous studies highlighting the detrimental health effects of excessive salt intake, research remains scarce in the field of mental health. Objective: This study aims to explore the relationship between the frequency of salt added to food and the risk of incident anxiety and depression. Methods: The prospective cohort study comprised 276,138 individuals from the UK Biobank who were initially free from anxiety and depression. Cox proportional hazard models were used to investigate the relationship between the frequency of salt added to food (categorized as never/rarely, sometimes, usually, and always) and the incident depression and anxiety. Results: Within the analyzed population of 276,138 individuals, the average age was 56.6 years, with males accounting for 48.6 % of the cohort. During a median follow-up of 14.6 years, 10,486 individuals developed depression, and 10,786 individuals developed anxiety. The multivariable-adjusted hazard ratios (HRs) for incident depression were 1 (reference), 1.10 (95%CI, 1.04-1.16), 1.19 (1.11-1.28), and 1.45 (1.32-1.59) (p trend <0.001). For incident anxiety, the adjusted HRs were 1 (reference), 1.08 (1.03-1.14), 1.08 (1.01-1.16), and 1.24 (1.12-1.37) (p trend <0.001). Adequate vegetable and fruit intake showed a modifying effect on the risk of incident depression and anxiety (p for interaction = 0.049 and 0.031, respectively). Conclusions: Higher frequency of salt added to food is linked to increased risk of anxiety and depression, while adequate vegetable and fruit intake may mitigate the detrimental effects of excessive salt consumption.