Dietary intake of B vitamins and their association with depression, anxiety, and stress symptoms: A cross-sectional, population-based survey

• We evaluated the relationship between dietary intake of a vitamin B and depression, anxiety, and stress in a 7387 Iranian adults. • This is the first study showing significant protective associated between biotin with depression, anxiety, and stress. • Findings showed that B6 intake was inversely associated with stress symptoms. • The role of B complex requires further investigation in randomized controlled trials. B vitamins have vital roles in the development, maintenance, and functioning of the brain, while severe deficiencies have been linked to increased psychological disorders. However, no published studies have examined the association between dietary intake of vitamin B and depression, anxiety, and stress symptoms in a general population. This cross-sectional study was done on 7387 Iranian adults aged 20-70 years within the population-based cohort study framework. A validated semi-quantitative Food Frequency Questionnaire (DS-FFQ) was used to ascertained vitamin B intake. Participants completed the Iranian validated version of depression, anxiety, and stress scale questionnaire 21 (DASS 21) to assess their psychological health. Multivariable logistic regression analysis was performed to analyze the association between vitamin B intake and psychological disorders. After adjustment for a wide range of confounders, higher intake of biotin was associated with a lower odds of depression (OR 0.71, 95% CI 0.55-0.91, P-trend=0.008), anxiety (0.71, 0.56-0.89, P-trend=0.003), and stress (0.58, 0.39-0.87, P-trend=0.01). An inverse relationship was found between B 6 and stress risk (0.50, 0.28-0.90, P-trend= 0.01). Moderate intake of thiamin (0.76, 0.61-0.94, P-trend=0.20), niacin (0.78, 0.62-0.97, P-trend=0.41), and pantothenic acid (0.80, 0.65-0.99, P-trend=0.05) were related to lower odds of anxiety. Additionally, moderate folic acid intake was associated with lower odds of depression (0.78, 0.61-0.99, P-trend=0.71). A subgroup analysis based on sex revealed that biotin's dietary intake reduced the risk of depression, anxiety, and stress, but this association was not significant in the male population. Cross-sectional nature of the data prevents causal associations. This study suggests that a higher intake of dietary B vitamins, especially biotin, was associated with a lower prevalence of depression, anxiety, and stress symptoms. The role of B vitamins requires further investigation in randomized controlled trials.