This study revealed a significant relationship between diet, exercises, and mental stress, providing novel insights into the occurrence and aggravation of mental stress.
In this study, we applied both logistic regression model and classification tree to analyze the factors related to mental stress. The logistic regression model is insufficient to deal with the collinearity of variables, while the CART is not affected by the collinearity problems among variables in the analysis. However, the quantitative explanation of the effect of individual factors is not as good as that of the logistic regression model[17]. Our analysis combines two methods, which are helpful to understand better the potential factors affecting mental health.
Besides age, gender, and marital status, increased consumption of fried food and fresh vegetables or fruits was found to be related to mental stress by both the logistic regression model and classification tree. Previous studies had shown that gender differences in the susceptibility of mental health [18–20]. Mental stress stimulates the activity of the hypothalamic-pituitary-adrenal axis and regulates mood through cortisol[21]. Aging could increase the basal level of cortisol in the brain[22], explaining why older people produce less stress through earlier negative feedback to hormone levels. Poverty was more likely to lead to mental disorders[23], and both married families and cohabitants benefited from the income of two adult earners, while cohabitants have still fared slightly worse than married families[24]. Reducing the intake of fried foods, which were rich in acrylamide and trans fatty acids, might benefit for mental health[25]. Furthermore, fresh vegetables or fruits could reduce depression by resisting the adverse impacts of oxidative stress[26].
We found that increased dessert and pickled or smoked food was related to an increased risk of mental stress. The benzo[a]pyrene in picked or smoked food is a carcinogen, and incomplete oxidation of glucose in dessert will produce metabolites such as lactic acid when vitamin B1 is insufficient in the body, affecting the activity of the central nervous system[27, 28]. There was, in addition, the small amount of consumption of fish to concern. Fish is rich in omega-3 polyunsaturated fatty acids, and many studies had concluded that proper intake of fish was beneficial to mental disorders[29, 30]. Among the female, quitting smoking or quitting drinking seemed to show more mental stress. It might be explained by the interruption of the way of catharsis aggravated the mental state[31]. Some studies showed that physical activity For males, we observed that eating less cereal and legumes could also increase mental stress. Legumes and cereal contain high levels of B vitamin with antioxidant properties [26]. A follow-up project supported that the legumes were a protective factor and the randomized clinical trial came out that the intervention focused on the B vitamin could reduce occupational stress[32, 33].
Our study had several limitations. First, self-assessment may not fully reflect the actual state of mental health. Second, the cross-sectional study design limited the ability to verify the causal relationship. Third, recalling bias could also affect the results.
In conclusion, our study showed a significant role of diet habits and behaviors in the risk of mental stress, which might provide novel insights into interventions for mental health.