Randomized clinical trial in healthy individuals on the effect of viscous fiber blend on glucose tolerance when incorporated in capsules or into the carbohydrate or fat component of the meal.

Background/objective: Addition of viscous fiber to foods has been shown to significantly reduce postprandial glucose excursions. However, palatability issues and the variability in effectiveness due to different methods of administration in food limits it use. This study explores the effectiveness of a viscous fiber blend (VFB) in lowering postprandial glycemia using different methods of incorporation.

Methods: Two acute, randomized, controlled studies were undertaken: Study 1: Twelve healthy individuals (mean ± SD, age: 36 ± 13 years, body mass index [BMI]: 27 ± 4 kg/m(2)) consumed 8 different breakfasts. All meals consisted of 50 g of available carbohydrate from white bread (WB) and 10 g margarine. Zero, 1, 2, or 4 g of the VFB was baked into WB or mixed with the margarine. Study 2: Thirteen healthy individuals (mean ± SD, age: 39 ± 17 years, BMI: 25 ± 5 kg/m(2)) consumed 6 test meals, consisting of 50 g of available carbohydrate from WB. Six capsules containing either cornstarch or VFB were taken at 4 different time points during the glucose tolerance test. After obtaining a fasting finger-prick blood sample, volunteers consumed the test meal over a 10-minute period. Additional blood samples were taken at 15, 30, 45, 60, 90, and 120 minutes from the start of the meal. For study 2, an additional fasting sample was obtained at -30 minutes.

Results: Study 1: Irrespective of VFB dose, glucose levels were lower at 30 and 45 minutes when VFB was mixed into the margarine compared to the control (p < 0.05). Incremental areas under the curve were significantly lower compared to control when 4 g of VFB was mixed into the margarine. Study 2: There was no effect of the VFB on postprandial glucose levels when administered in capsules.

Conclusion: Incorporation of VFB into margarine was more effective in lowering postprandial glycemia than when the VFB was baked into bread and no effect when given in capsules.