Objective: To study the effects of staple food on the glycemic responses through a controlled feeding trial.
Methods: In November 2020, two groups of volunteers with different staple food habits(the rice group, n=35, and the wheat group, n=35), were recruited from Changzhi Medical College in Shanxi Province. They were subjected to a two-stage feeding trial, in which their staple food habits were maintained in the first stage(staple food fortification period, 4 weeks) and then swapped in the second stage(staple food swap period, 4 weeks), while keeping the rest of the dietary components same. A continuous glucose monitoring system was used to monitor the glycemic response of glucose, steamed buns and steamed rice, equivalent to 50 g of available carbohydrate(CHO). Blood glucose level up to 120 minutes postprandial, incremental area under the curve(iAUC) and glycemic index(GI) were analyzed.
Results: During the staple food fortification period, the glycemic response to steamed buns at 15 min(5.43±0.69 vs.5.14±0.50 mmol/L, P=0.047), 30 min(6.63±0.98 vs.6.10±0.70 mmol/L, P=0.012), 45 min(6.81±1.15 vs.6.21±0.67 mmol/L, P=0.011) and 60 min postprandial(6.03±0.96 vs.5.56±0.59 mmol/L, P=0.017) in the rice group were higher than the wheat group, and the trends for blood glucose fluctuation during the 120 minutes after consuming steamed buns were different between the two groups. During the staple food swap period, the 120 min iAUC(83.24±30.15 vs.69.32±26.25 mmol·min/L, P=0.032) and GI(88±24 vs.75±33, P=0.041) of the rice group to steamed buns were higher than the wheat group. Comparing the differences between the two groups in the staple food exchange period and the staple food intensification period, the rice group had an increased glycemic response to steamed buns(P=0.007), while the wheat group had an increased glycemic response to glucose(P<0.001), steamed buns(P<0.001) and steamed rice(P=0.018). The 120 min iAUC of steamed buns in the rice group increased(83.24±30.15 vs.70.12±26.02 mmol·min/L, P=0.029), and the 120 min iAUC of rice in the wheat group(69.75±32.32 vs.54.87±20.43 mmol·min/L, P=0.040) increased.
Conclusion: Even to the same food, there are significant differences in the glycemic responses of people with different staple food habits, and short-term changes in the intake of staple food will lead to differences in the glycemic response.
Keywords: dietary habits; glycemic index; glycemic response; staple foods.