Responses of blood glucose and C-peptide to five Chinese starchy foods

Forty-nine patients with non-insulin-dependent diabetes mellitus (NIDDM) were randomly divided into four groups (10-18 patients per group) to compare the responses of blood glucose and C-peptide to some Chinese starchy foods. Ten healthy subjects were used as controls. After an overnight fast, the blood samples were drawn at fasting and 30, 60, 120, 180 minutes postprandially to measure plasma glucose and serum C-peptide levels. Bun, which was made from refined wheat flour and similar to white bread, was used in the assessment as the reference food. Other test foods included rice, lotus seed, seed of gordon euryale, and rhizome of common yam. There was only one kind of food in each test meal, and each serving contained 50 g of carbohydrate. With both glycaemic index (GI) and C-peptide index (CI) of bun set as 100 in this study, the GI and CI respectively were: rice 89 and 91; lotus seed 62 and 72; seed of gordon euryale 102 and 102; rhizome of common yam 103 and 95. The GI and CI of lotus seed were significantly lower than those of other test foods. It appears that lotus seed may have a beneficial effect in NIDDM patients, and may be one of the more appropriate foods for diabetic patients.