Effect of a Novel High Fiber Rice Diet on 24-Hour Glycemic Responses in Asian Indians Using Continuous Glucose Monitoring: A Randomized Clinical Trial.

BACKGROUND: We have recently demonstrated a medium glycemic index for novel high fiber white rice (HFWR) variety compared to regular white rice (RWR). However, substituting HFWR for RWR during the whole day's diet may provide extended benefits. The current study aims to assess the 24 h glycemic responses of a HFWR diet compared to a RWR diet. METHODS: Continuous glucose monitoring (CGM) was used to assess the glycemic profile in 18 overweight, non-diabetic Asian Indians aged 25 to 50 in a randomized cross-over design. The volunteers were provided with iso-caloric (≈2100 kcal/day) HFWR or RWR based diets for four continuous days and switched diets after appropriate washout. Fasting blood samples for insulin assessments were collected at baseline and at the end of 4 day feeding. The glucose response in terms of incremental area under the curve (IAUC) was recorded. General linear model was used to assess the adjusted mean change of fasting insulin level of HFWR compared to RWR. Age and sex were adjusted as confounders in the model. RESULTS: The average 24 h glucose response for HFWR was significantly lower (IAUC 66.3 ± 3.1 mg-5 min/dL) than RWR (IAUC 79.8 ± 5.7 mg-5 min/dL). The adjusted mean change in fasting insulin levels from baseline was also lower for HFWR compared to RWR. HFWR elicited a 34% and 30% lower 24 h glycemic and insulin response respectively, compared to RWR. CONCLUSION: Replacing RWR with HFWR may be a healthier alternative for Asian Indians who are at a higher risk of developing type 2 diabetes.

Effect of a low molecular weight, high-purity ß-glucan on in vitro digestion and glycemic response.

ß-Glucans are believed to lower postprandial glycemia due to their ability to increase viscosity and slow down gastric emptying. The effect of high-purity barley ß-glucan (Glucagel) was tested on in vitro starch digestibility and glycemic response of chapattis. In a randomized controlled crossover trial, 10 healthy human subjects consumed chapattis containing 0, 4 and 8% ß-glucan on different occasions. Capillary blood samples were collected before and at 0, 15, 30, 45, 60, 90 and 120 min after consuming the chapattis. There was no significant difference either in the amount of glucose released after in vitro digestion or in the glycemic response to chapattis with 0, 4 and 8% ß-glucan (P>0.05). It may be concluded that low molecular weight barley ß-glucan, although of 75% purity, was not effective in lowering glycemic response possibly due to its inability to influence starch digestion and particle breakdown during in vitro digestion.