Glycemic Response to Black Beans and Chickpeas as Part of a Rice Meal: A Randomized Cross-Over Trial

Abstract

Legumes, such as black beans (Phaseolus vulgaris L.) and chickpeas (Cicer arietinum L.), have a low glycemic index, and may reduce the glycemic load of meals in which they are included. Although the low glycemic response of beans consumed alone has been documented, few studies have examined the glycemic response to traditional food combinations such as black beans and rice or chickpeas and rice. This randomized cross-over study examined the glycemic and insulinemic impact of 50 grams of available carbohydrate from three test meals: plain white rice (control), black beans with rice, and chickpeas with rice among healthy adult women (n = 12, 18-65 years). Treatments were consumed on different mornings, a minimum of 7 days apart. Blood samples were collected at time 0 (fasting), and at 30, 60, 90, and 120 min postprandial, and were subsequently analyzed for glucose and insulin concentrations. Glucose response based on the incremental area under the curve showed a significant difference by treatment (p = 0.027). Changes in blood glucose concentrations were significantly different for the black bean meal and the chickpea meal in comparison to rice alone at 60 min (p = 0.026 and p = 0.024), 90 min (p = 0.001 and p = 0.012) and 120 min post prandial (p = 0.024; black bean meal). Findings indicate that combinations of black beans and chickpeas with white rice improve glycemic response, providing evidence that has promising implications for dietary guidance to reduce postprandial glucose and related health risks through traditional food patterns.

Keywords: beans; blood glucose; glycemic response; insulin; insulin response; legumes; post-prandial; pulses.

Conflict of interest statement

The authors declare no conflict of interest

Figures

Figure 1

Effect of bean interventions on change in plasma glucose concentrations from fasting. Points denote mean glucose concentration at each data collection timepoint and error bars denote standard error of means. Mean fasting glucose values were not significantly different between treatment groups (91.68 (SEM 2.42), 89.54 (SEM 1.83), and 89.64 (SEM 5.70) mg/dL for white rice, black beans and white rice, and chickpeas and white rice, respectively). Results of a post-hoc paired t-test indicated that the glucose response curve was significantly different at 60 (p = 0.026), 90 (p = 0.001), and 120 (p = 0.024) for black beans (n = 12), and at 60 (p = 0.024) and 90 (p = 0.012) for chickpeas (n = 9) compared to control (rice alone). A trend was observed at the 120 min timepoint between chickpeas and rice and the white rice control meal (p = 0.072).

Figure 2

Effect of bean treatments on change in plasma insulin from fasting values. Points denote mean insulin concentration at each data collection timepoint and error bars denote standard error of means. Results of a post-hoc paired t-test indicated that the insulin response curve was significantly different at 30 (p = 0.037) for black beans (n = 12), and at 30 (p = 0.026) for chickpeas (n = 9) compared to the white rice control meal.

Figure 3

One-way Analysis of Variance of glucose iAUC was significantly different by treatment (p = 0.027). Tukey post-hoc tests indicated a significant difference between chickpeas and control (p = 0.047), and a trend was observed between black beans and control (p = 0.058). * p < 0.05. Bars denote mean insulin iAUC values and error bars denote standard error of means.

Figure 4

Insulin iAUC was not significantly different by treatment (p > 0.05). Bars denote mean insulin iAUC values and error bars denote standard error of means.