Asia has a growing diabetes problem. With over 400 million adults in the region living with type 2 diabetes (T2D) as of 2024, health services face the looming challenge of providing adequate care for years to come. This is fuelling a search for preventive measures against T2D, particularly in people with prediabetes, who may appear healthy but carry tell-tale metabolic signs of a higher risk of future disease.
At the A*STAR Singapore Institute of Food and Biotechnology Innovation (A*STAR SIFBI), researchers such as Melvin Leow, Deputy Head of the Nutrition & Digestive Health Division, are looking to food and gut health for answers. While previous studies have linked legume-rich, plant-based diets with better blood sugar control and metabolic health, it’s less clear just how they affect T2D progression.
“Legumes are widely known to be nutritious, but their specific effects on metabolic health within a calorie-restricted diet hasn't been rigorously evaluated in populations at higher risk of T2D,” said Leow.
For new insights in this area, Leow and A*STAR SIFBI colleagues—including Alvin Surya Tjahyo and Sumanto Haldar, respectively a Senior Officer and Principal Investigator at the time—worked with the National University of Singapore and food processing company Wilmar International. The collaboration was originally initiated by A*STAR Senior Adviser Christiani Jeyakumar Henry, with Kevin Lim serving as the lead scientist from Wilmar.
Together, they conducted a randomised controlled trial of two 16-week diet plans among 127 prediabetic Chinese adults in Singapore. While both diets were calorie-controlled to similar amounts, the intervention diet used legumes as its primary protein source, while the control diet used chicken or fish alternatives.
“We sought to understand how specific dietary modifications may impact cardiometabolic health and T2D progression risk in at-risk groups,” said Leow, who added that their study was the first of its kind undertaken in the Asian region.
With participants equally divided between the two diet plans, the team monitored their weight, blood sugar, other metabolic markers and gut microbiome compositions. They found that both groups experienced modest weight loss; however, only the intervention group showed significant reductions in LDL and total cholesterol, as well as HbA1c, a long-term marker of blood glucose control.
The team also noticed that within the study’s first two weeks, participants on the legume-rich diet exhibited an early and sustained rise in fibre-loving gut bacteria such as Eubacterium rectale, Roseburia sp. and Bifidobacterium sp., which are associated with improved glucose and lipid metabolism. Conversely, bacterial species linked to poor intestinal health and metabolic outcomes, such as Ruminococcus sp. and Bacteroides sp., went through a sustained decline.
“Overall, we found that a multi-component, legume-rich diet can improve cardiometabolic health beyond what calorie restriction can achieve alone, with direct links to favourable changes in gut bacteria,” said Leow. “This study reinforces the importance of whole-diet based approaches and gut microbiome modulation in managing T2D and other chronic metabolic diseases.”
The team plans to explore the sustainability and effectiveness of such dietary interventions at a larger scale in community settings, as well as nutrition strategies tailored to individual microbiome profiles.
The ASTAR-affiliated researchers contributing to this research are from the A*STAR Singapore Institute of Food and Biotechnology Innovation (A*STAR SIFBI) and A*STAR Institute for Human Development and Potential (A*STAR IHDP).
