Comparison of vegan and non-vegan diets on memory and sleep quality

Summary: Background and aims: It is widely acknowledged that the quality of nutrition affects many aspects of physical and mental performance. A vegan diet is associated with superior cardiovascular and cerebrovascular conditions. Mediterranean diets (high fruit and vegetable content) are linked with reduced risk of neurodegenerative diseases and improved performance on cognitive. The aim of the present study was to evaluate the effects of diet on memory and sleep quality. Materials and methods: Verbal memory and sleep quality were assessed in a cohort of 62 adults aged 40 and above. Using a modified Mediterranean Diet Adherence Screener, the participants were divided into the categories of vegan, vegetarian, pescatarian, omnivores with low meat/fish consumption, and omnivores with high meat/fish consumption. The California Verbal Learning Test was used to assess verbal learning memory, and the Pittsburg Sleep Quality Index was used to assess sleep quality. Results: The diet group with the best performance was pescatarian (M = 118.2), followed by vegetarian (M = 117.6) and vegan (M =116.0). The group with the lowest performance was omnivore high (M = 104.7). Females performed better than males in every diet group except vegetarian. Analysis of variance showed a main effect of diet on delayed recall, F(4, 57) = 2.823, P = .033, ηp 2 = .165. There was a significant difference among the diet groups on the delayed recall, where vegetarians had the highest scores (116.43) followed by pescatarians (116.20), vegans (115.21), omnivore lows (105.41) and lastly omnivore highs (99.43). Conclusions: Diet was found to have a significant effect on memory but no significant effect on sleep quality. The sample size may have been insufficient to capture the effects of diet on sleep. To definitively establish the relationships between diet patterns and quality of cognitive functioning and sleep, further research is required. The results of this study cast doubt on the hypothesis that the consumption of animal products boosts memory performance.