Legume-enriched diet improves metabolic health in prediabetes partially mediated through gut microbiome: a randomized controlled trial

Healthy dietary patterns rich in legumes can improve metabolic health, although their additional benefits in conjunction with calorie restriction has not been well-established. We investigated effects of a calorie-restricted, legume-enriched, multicomponent intervention diet compared with a calorie-restricted control diet in 127 Chinese prediabetes participants, living in Singapore. The study was a 16-week, single-blind, parallel-design, randomized controlled trial (n=63 intervention group (IG), n=64 control group (CG)). Primary outcomes were markers of glycemia and all measurements were taken at 2 or 4-weekly intervals. At the end of 16 weeks, both groups had significantly lower BMI compared with baseline, with minimal difference between groups. The IG had significantly greater reductions in LDL cholesterol, total cholesterol and HbA1c compared with CG, alongside increases in fibre degrading species in IG, mediated through metabolites such as bile acids and amino acids. A legume-enriched, multicomponent intervention diet can improve metabolic health in a prediabetes population, in addition to benefits obtained from calorie restriction alone, partially mediated through changes in gut microbial composition and function.Trial registration: Clinical Trials NCT04745702.