Effects of plant-based diet on metabolic parameters, liver and kidney steatosis: a prospective interventional open-label study

This interventional single-centre prospective open-label study aims to evaluate the effects of a vegan diet, compared with a vegetarian and omnivorous diet, on metabolic parameters, insulin sensitivity, and liver and kidney steatosis in healthy adults. The study included fifty-three omnivorous participants aged 18-40 years, BMI 18-30 kg/m², without any chronic disease, chronic medication use, active smoking or significant alcohol consumption. All participants were omnivorous at baseline and selected to continue an omnivorous diet or transition to a vegetarian or vegan diet, with follow-up over 6 months. Anthropometric measurements, biochemical parameters and liver and kidney steatosis were assessed at baseline and after six months using MRI-proton density fat fraction. Primary outcomes included changes in liver and kidney steatosis, while secondary outcomes were alterations in anthropometric and biochemical markers. Among fifty-three participants, eighteen followed an omnivorous diet, twenty-one adopted a vegetarian diet and fourteen transitioned to a vegan diet. Dietary interventions did not result in statistically significant changes in BMI, fat mass, fat percentage or muscle mass over 6 months. However, statistically significant improvements in systolic and diastolic blood pressure, favouring the vegan diet, were observed. We aimed to control for potentially confounding variables to ensure the reliability of these findings. We have demonstrated a better decline in steatosis at the lower kidney pole, the total hilus and the Liver 6 index in vegans. We demonstrated that a plant-based diet is associated with improvements in several metabolic parameters and may reduce liver and kidney steatosis.