Objectives: Although animal studies show the advantageous impact of allium-derived compounds on brain function, there is no epidemiological study on the link between allium vegetable consumption and mental disorders.
Methods: 447 Iranian women (20-50 years) were included in this cross-sectional study. A trained nutritionist assessed participants' habitual dietary intake by a valid and reliable 168-item food frequency questionnaire. To evaluate mental disorders, a validated version of the Depression, Anxiety, and Stress Scale-21 (DASS-21) was used, which is a 21-item self-reported structured scale consisting of three subscales: depression, anxiety, and psychological distress. The subscale had seven questions each, with responses on a four-point Likert scale [0 (never), 1 (little), 2 (sometimes), 3 (always)]. A bimodal scoring method (0-0 to 1-1) estimated the final score for each subscale between 0 and 21. Scores of ≥10 for depression, ≥8 for anxiety, and ≥15 for psychological distress indicated mental disorders. Logistic regression calculated odds ratio (OR) and 95% confidence interval (95CI%) for the association of allium vegetable consumption with depression, anxiety, and psychological distress.
Results: Participants were categorized based on their weekly consumption of total allium vegetables ( < 141.96; 141.96-222.95; >222.95 g/week), onion ( < 17.50; 17.50-74.97; >74.97 g/week) and garlic ( < 0.28; 0.28-4.97; >4.97 g/week). After accounting for potential confounders, an inverse association was observed between total allium vegetable consumption and depression (OR: 0.54 [95CI% 0.30, 0.94] Ptrend: 0.02), anxiety (0.51 [0.29, 0.90] Ptrend: 0.01), and psychological distress (0.37 [0.21, 0.65] Ptrend: 0.0001). Onion consumption was also inversely linked to depression (0.47 [0.26, 0.84] Ptrend: 0.008), anxiety (0.50 [0.28, 0.89] Ptrend: 0.01), and psychological distress (0.44 [0.25, 0.78] Ptrend: 0.004). However, there was no significant association between garlic consumption and any of the subscales of mental disorder.
Conclusions: Results indicate that the consumption of allium vegetables may be beneficial in preventing depression, anxiety, and psychological distress. Longitudinal studies are required to establish a causal relationship between the observed associations.
Funding Sources: First author is funded by a CIHR Vanier Scholarship.
