Association between mealtime distribution of macronutrient and mental health in apparently healthy Iranian adults: a cross-sectional study

Mental health (MH) disorders are one of the most prevalent global public health issues for a significant portion of the population. The aim of this study was to investigate the relationship between the mealtime distribution of macronutrients and MH in Iranian adults. We used a convenience sampling technique to perform this cross-sectional study. The Depression, Anxiety, and Stress Scale (DASS-21) was used to assess the MH outcome. Dietary consumption was assessed using multiple 24-hour dietary recalls. The coefficient of variation (CV) was then used to compute the macronutrient distribution at mealtime. In all, 54.6%, 53.9%, and 56.6% were classified as having anxiety, depression, and stress symptoms, respectively. The CV scores for carbohydrate were relatively evenly distributed across all meal times, with a mean of 0.38, 0.38, and 0.39 for breakfast, lunch, and dinner, respectively. We observed no significant association between the mealtime distribution of carbohydrates and mental health indices in any of the analyzed models. However, a more skewed distribution of protein intake towards dinner (i.e. a higher protein CV value) was positively associated with anxiety (OR: 1.69; CI: 1.02-2.78) and stress symptoms (OR: 1.93; CI: 1.17-3.16). We also observed a significant association between fat distribution and depression symptoms, with subjects in tertile 2 having higher odds of depression compared to T1 (OR: 1.63; CI: 1.00-2.63). In conclusion, a skewed distribution of protein and fat intake may be associated with mental health problems. Future studies are warranted to validate these findings and gain a better understanding of the underlying mechanisms.