The association between dairy products and psychological disorders in a large sample of Iranian adults.

BACKGROUND: Dairy products contain certain nutrients that are useful in mental disorders. This study aimed to assess the associations between dairy products and psychological disorders in a large sample of Iran, a Middle Eastern country. METHODS: This cross-sectional study was undertaken on 7387 adults. Data on dietary intakes were obtained using a validated Food Frequency Questionnaire. Psychological health was assessed by the Iranian validated version of depression, anxiety, and stress scale 21. Multivariable logistic regression analysis was performed to analyze the association between dairy intake and psychological disorders. RESULTS: After adjustment for potential confounders, total milk consumption (OR for the highest vs. lowest tertile: 0.73, 0.58-0.92) and total yogurt consumption (0.78, 0.62-0.97) were associated with decreased odds of depression. An inverse relationship was found between total dairy (0.73, 95% CI 0.590.91), total milk (0.72; 0.58-0.88), kashk (0.79, 0.65-0.96), and yogurt drink (0.80, 95% CI 0.65-0.98) consumption and anxiety symptoms. Higher intake of cheese was related to greater odds of stress (1.52, 1.02-2.26). No association was found between the consumption of high-fat dairy, low-fat dairy, low-fat milk, low-fat yogurt, high-fat yogurt, cheese, kashk, yogurt drink, and depression. Also, there is no association between dairy products and stress symptoms. This association was significant among men and women and high-fat and low-fat products in the total adjusted stratified analysis models. CONCLUSIONS: Findings of this study revealed that both high-fat and low-fat dairy products are associated with a reduced prevalence of psychological disorders. Still, more prospective studies are required to confirm these associations.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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 B6 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. LIMITATIONS: Cross-sectional nature of the data prevents causal associations. CONCLUSIONS: 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.