Connections Between Diet and Mental Health: Comparing Participants Randomized to Vegan and Omnivorous Diets in the Nutritious Eating With Soul (NEW Soul) Study.

Research on vegan diets and mental health shows mixed results but most of the studies have been cross-sectional and among white populations. This study examined changes in perceived stress and mental wellbeing among African American adults aged 18-65 years (N = 159) with overweight/obesity, who were randomized to vegan or omnivorous diets in a 2-year nutrition intervention. Changes in outcomes were assessed using intent-to-treat analysis with mixed model repeated measures. Both groups experienced decreased stress from baseline, seen at 6, 12, and 24 months for the omnivorous group and at 12 and 24 months for the vegan group. The omnivorous group showed improved mental wellbeing at 24 months. There were no differences in changes between the groups at any timepoint (P > 0.05) for stress and mental wellbeing. There were no differences between adherent vegan vs adherent omnivorous participants in changes in either outcome at any timepoint (P > 0.05). Prior research suggests increased stress and reduced mental wellbeing or reduced stress and increased mental wellbeing among individuals following a vegan diet, but this study found no difference in changes in stress and mental wellbeing between participants randomized to vegan or omnivorous diets.