The regular consumption of soy products has long been associated with the reduced incidence of type 2 diabetes, and there has been an increasing interest in the glycaemia-reducing potential of rice bran and its components.
In this study, researchers from the Clinical Nutrition Research Centre in Singapore, Health Care R&D at Sunstar Inc., and the National University of Singapore investigated whether consuming soy milk with the addition of rice bran can reduce the glycaemic response to a carbohydrate-heavy meal.
Seventeen healthy Asian men (BMI: 18.5 to 29 kg/m2) participated in this randomised crossover trial.
On four occasions, they consumed white bread (two times) and white bread with two different soy milks differing in protein and rice bran content.
Blood samples were taken to measure glucose and insulin response over three hours.
"Taking the glycaemic index (GI) value of white bread as a reference value of 100, the GI of white bread when co-ingested with rice bran soy milk (RBS) was 83.1 (±7.7) and sugar-free soy milk (SFS) was 77.5 (±10.1), both were lower than white bread," wrote the researchers.
While the insulin response of both soy milk treatments was similar to white bread, the glucose / insulin ratio of RBS and SFS were 43.1 (±6.1) and 60.0 (±17.0) and were lower (p < 0.05) than white bread (123.5 ± 21.1) during the first 30 minutes after consumption.
In a previous study, the same researchers found that the co-ingestion of soy milk reduced the glycaemic response of white bread by about 25%.
This present study demonstrated that consuming soy protein derived from soy milk at lower doses (rice bran soy milk: 3.4g, sugar-free soy milk: 7.8g, versus the previous study's 11.8g) is still capable of lowering the glycaemic response by about 17% for RBS and 23% for SFS.
"This finding aligns with our hypothesis that co-ingestion of soy milk with a carbohydrate meal reduces the glycaemic response, and this can be a potential dietary strategy to improve glycaemic control," they concluded.
The research was supported by the Agency for Science, Technology, and Research (A*STAR) and partially by a grant from Sunstar Group (Japan).
"Co-Ingestion of Rice Bran Soymilk or Plain Soymilk with White Bread: Effects on the Glycemic and Insulinemic Response"
Authors: Christiani Jeyakumar Henry, et al.
Dr Sumanto Halder from Singapore's Clinical Nutrition research Centre will speaking at our forthcoming Healthy Ageing APAC Summit, where he will be shedding light on the anti-diabetic properties of a raft of functional foods. Find out more here.