Vegetarian diet and mental health: Cross-sectional and longitudinal analyses in culturally diverse samples

Background: Vegetarianism is linked with better physical health, but also to increased anxiety and depression. The aim of the present study is to examine the relationship between vegetarianism and both positive and negative mental health, across cultures and over time. Method: Self-report questionnaire data were obtained from a large-scale multi-national cross-sectional sample including 2007 representative adult members of the German population, 3020 representative adults from Russia, and 3038 representative adults from the USA. Participants for the longitudinal analyses include university students from Germany (1608) and China (12,744). Statistical models included multiple linear regression, longitudinal linear models and longitudinal logistic models. Results: Vegetarianism diet is not reliably related to positive or negative mental health in US and Russian representative samples or in German representative or student samples. Vegetarianism is related to slight increases over time in anxiety and depression in Chinese students. Conclusions: Vegetarianism is not associated with mental health in the US, Russia, or Germany, but is associated with anxiety and depression in China in this study. Future studies should examine the nuances of vegetarianism in more detail and their links with mental health, including dietary composition and cultural beliefs and economic circumstances. Future researchers in this area may also want to consider the effects of experimental manipulation of diet on mental health outcomes over time.