Nutrition and health status in the follow-up of the risks and benefits of a vegan diet (RBVD) study

Abstract To examine health risks and benefits of a vegan diet, the RBVD study was conducted in 2017 and followed up in 2021. The present paper evaluated dietary nutrient intake and status together with systemic cardiometabolic health-related biomarkers and examinations among vegans and omnivores in 2017 and 2021. Our study included n = 24 vegans and n = 26 omnivores (aged 30–60 years at baseline), who participated at both time points. Dietary nutrient intake was determined by 3-day weighed food records and an interview about supplement use. Nutrient status and health-related biomarkers were measured in blood and 24-h urine samples. Despite similar energy intake, fibre intake was higher and saturated fat intake was lower in vegans compared to omnivores at both time points. Vitamin B 12 status did not differ between both groups at any time. Compared to omnivores, vegans had higher blood concentrations of folate and 25-hydroxyvitamin D in 2021, and lower vitamin A and B 2 concentrations in 2017. Blood concentrations of magnesium and copper were similar in both groups at both time points, while urinary calcium excretion was lower in vegans compared to omnivores in 2021. Selenium and zinc serum concentrations were consistently lower in vegans. Compared to omnivores, vegans had lower serum total and LDL cholesterol as well as plasma HbA1c at both time points. Over a four-year period, significant nutritional intake, status and health biomarker differences were observed between vegans and omnivores. Future research is needed to clarify the associated long-term health risks and benefits.