Guzman, G., Xiao, D., Liska, D., Mah, E., . . . Edirisinghe, I. (2021). Addition of orange pomace attenuates the acute glycemic response to orange juice in healthy adults. The Journal of Nutrition, 151(6), 1436. doi:10.1093/jn/nxab017

Abstract:

Background Fiber is an important part of a healthy diet and is known to attenuate postprandial glycemia. Orange pomace (OP) is a by-product of orange juice (OJ) production and is a rich source of fiber. Objective Two separate studies determined the impact of added OP to 100% OJ on postprandial glycemic response compared with sugar-matched OJ or whole orange fruit (WOF). Methods Study 1 included 17 adults [65% female, age 39.3 ± 3.1 y, and BMI (in kg/m²) 24.6 ± 0.7], and study 2 included 45 different adults (47% female, age 25.1 ± 4.3 y, and BMI 22.5 ± 1.6). Studies were conducted at separate locations using a randomized, 3-arm, crossover design to test the glycemic response to sugar-matched OJ, OJ with 5 g fiber from OP (OPF), or WOF. The primary outcomes were 2-h glucose incremental area under the curve (iAUC) in study 1, analyzed by repeated measures ANOVA, and maximum glucose concentration (C_max) in study 2, analyzed using PROC MIXED (ANCOVA). Glucose and insulin concentrations were measured at fasting and multiple time points over 2 h after test product consumption (study 1, serum; study 2, plasma). Results In study 1, glucose iAUC was not significantly lower in OPF compared to the OJ or WOF (825 ± 132 compared with 920 ± 132 and 760 ± 132 mg · min · dL⁻¹, respectively, P = 0.57 for both). In study 2, glucose iAUC was significantly lower in WOF compared with OPF and OJ (689 ± 70.7 compared with 892 ± 70.7 and 974 ± 70.7 mg · min · dL⁻¹, P = 0.02 and 0.001, respectively). Data from both studies indicated OPF reduced C_max compared with OJ and that the reductions were comparable to WOF (study 1: OPF, 115 ± 4.06 compared with OJ, 124 ± 4.06 and WOF, 114 ± 4.06 mg · dL⁻¹, P = 0.002 and 0.75, respectively; study 2: OPF, 128 ± 1.92 compared with OJ, 136 ± 1.92 and WOF, 125 ± 1.92 mg · dL⁻¹, P = 0.001 and 0.28, respectively). Conclusion Data from both studies demonstrated no significant effect of OPF on postprandial iAUC compared with OJ. However, adding OP into OJ attenuates the postprandial glucose C_max, and the responses were comparable to WOF in healthy adults.