Plant-Based, Vegetarian, Vegan, and Mental Health (Adult Population)

The purpose of this 2021 review/meta-analysis was to evaluate the association between vegan or vegetarian diets with cognitive and mental health. The authors state that although vegetarian and vegan diets provide health benefits, they may also lead to nutritional deficiencies. This review goes on to investigate its link with cognition and mental health since disorders in these domains contribute to a high economic burden. Firstly, two authors selected original observational or interventional human studies of vegan/vegetarian diets that were published on online databases such as PubMed, Scopus, ScienceDirect and Proquest. Thirteen studies were included in this review, providing data of 17809 participants. There was no significant correlation between diet and the continuous depression score, stress, well-being, or cognitive impairment. Vegans/vegetarians were found to be at higher risk of depression, but they also showed lower anxiety scores. Heterogeneity (variation) was large, which explains the numerous differences observed in subgroup analyses. In conclusion, vegan or vegetarian diets were related to increased odds of depression and lower anxiety scores. Higher risk of anxiety was shown in vegetarians/vegans under the age of 26 years, and in studies of higher quality. Thus, more studies with higher overall quality are required to make clear positive or negative associations and conclusions.