Causal relationships between dietary habits and five major mental disorders: A two-sample Mendelian randomization study

To explore the causal relationship between dietary habits and five major mental disorders using the two-sample Mendelian randomization (MR) analysis.This study was based on the summary data of the genome-wide association study (GWAS) on diet and five major mental disorders in the European population. The genetic locus data of five major mental disorders (mania, bipolar disorder, manic depression, depression, schizophrenia) from those who never eat eggs, dairy, wheat, and sugar were used. Two-sample MR analysis was conducted to evaluate the causal relationship between diet and five major mental disorders.This study revealed a causal relationship between "Never eat Wheat products" and all five types of mental disorders (mania, bipolar disorder, manic depression, depression, schizophrenia), demonstrating a significant negative correlation (P < 0.05). However, no significant causal relationship was observed between "Never eat Sugar or foods/drinks containing sugar" and any of the five mental disorders (P > 0.05). Furthermore, the study found that the statement "Never eat eggs, dairy, wheat, sugar: I eat all of the above" had a causal relationship with mania, bipolar disorder, and manic depression, showing a significant positive correlation (P < 0.05). However, this statement did not exhibit a significant causal relationship with depression and schizophrenia (P > 0.05).There was a negative correlation between never eating wheat products and the five mental disorders (mania, bipolar disorder, manic depression, depression, schizophrenia), indicating that never eating wheat products may reduce the risk of mental disorders.