High-molecular-weight barley β-glucan in chapatis (unleavened Indian flatbread) lowers glycemic index

Food products incorporated with soluble dietary fiber β-glucan have shown varying effects on postprandial glycemia. The objective of the present study was to test the hypothesis that a food product fortified with barley β-glucan and subjected to minimum processing and mild cooking might be effective in lowering glycemic response. In a randomized, single-blind, controlled crossover trial, 8 healthy human subjects (3 men, 5 women; aged 26-50 years; body mass index, <30 kg/m2) consumed unleavened Indian flatbreads called chapatis containing high-molecular-weight barley β-glucan at doses of 0, 2, 4, 6, and 8 g on different occasions. Capillary blood samples were collected at 0, 15, 30, 45, 60, 90, and 120 minutes after consuming the chapatis. The incremental area under the glucose curve values for all the 5 different types of chapatis were significantly low (P < .001) compared with reference food glucose. The incremental area under the glucose curve of chapatis containing 4 and 8 g β-glucan were significantly lower than control chapatis (P < .05). Postprandial blood glucose was significantly reduced at 45 minutes by chapatis containing 4 g (P < .05) and 8 g β-glucan (P < .01) and at 60 minutes by chapatis with 8 g β-glucan (P < .01). The glycemic index (GI) values of chapatis with 4 and 8 g β-glucan were 43% to 47% lower (GI, 30 and 29, respectively) compared with chapatis without β-glucan (GI, 54). We conclude that barley β-glucan significantly reduces GI of chapatis, particularly at doses of 4 and 8 g per serving.