A Novel Nutritional Supplement Reduces Postprandial Glucose Response in Healthy Individuals in a Randomised, Placebo-Controlled, Crossover Clinical Study

Abstract

Background: Sugar laden foods and carbohydrate rich diets with high glycaemic index intake are associated with weight gain, increased incidence of diabetes and is linked with increased cardiovascular risk. A blend of mulberry leaf extract and apple peel extract (Glubloc™) may reduce postprandial blood glucose surge and insulin response following dietary carbohydrate intake by limiting its digestion and uptake from the gut.
 Methods: In this randomised, placebo-controlled, crossover study, thirty healthy male and female subjects were supplemented with either placebo or Glubloc™, 10 min before a carbohydrate and sugar rich meal intake. Changes in postprandial blood glucose (upto120 minutes) and insulin levels (at 60 minutes) were measured as the primary endpoints. Changes in blood glucose incremental area under the concentration curve (iAUC), maximum concentration (Cmax) and peak time (Tmax) were compared.
 Results: Thirty adults (mean age 31±7.2 years, BMI 24±3.8 kg/m2) completed the study and the Glubloc™ blend relative to placebo significantly reduced glucose iAUC at 0.5 h (− 38%, p < 0.0003), 1.0 h (− 30%, p = 0.0007), 1.5 h (− 29%, p = 0.0008), and 2.0 h (− 26%, p = 0.002). A statistically significant reduction in 1 h insulin levels (− 35%, p = 0.029) was observed. 
 Conclusion: A single dose supplementation of Glubloc™ significantly reduced the postprandial blood glucose spike and serum insulin levels. The observation of a significant glucose reduction paralleled with a significant lower insulin response supports a reduced gastrointestinal glucose absorption. None of the subjects experienced any major gastrointestinal side effects. This study builds a body of evidence that the combination of white mulberry leaf and green apple peel extracts (Glubloc™) can be a useful supplement to manage postprandial glucose levels, further studies are necessary to evaluate its potential in type 2 diabetes and the regulation of dysglycaemia.