Consideration of the validity of glycemic index using blood glucose and insulin levels and breath hydrogen excretion in healthy subjects

AimAlthough glycemic index (GI) is very important in choosing appropriate foods for patients with diabetes mellitus, GI itself does not provide sufficient information for choosing adequate foods. The validity of GI is considered by measurement of blood glucose and insulin levels, and breath hydrogen excretion, testing several cultivars in the same type food.MethodsTwelve females, 23.8 y participated in this within-subject, repeated-measures study. To clarify variations in GI in inter-cultivars of various foods, we examined four white rice and three potato cultivars and three noodle brands. Starchy-foods with a glucose equivalent of 50 g were repeatedly and randomly given to each subject. Blood and end-expiration were collected at selected periods.ResultsThe significant difference of GI and insulinemic index (II) was not observed among the four white rice cultivars, though II of one cultivar were smaller than those of other three white rice cultivars. GI of three potato cultivars was relatively small, but the range of II was very large among three cultivars. Moreover, GI did not correspond to II among three noodle brands. AUC-3 h-glucose and AUC-3 h-insulin scores of white rice and noodle were significantly larger than those for 2 h. The amount of breath hydrogen excretion showed a negative correlation to GI of tested foods.ConclusionsWe should recognize that rare foods in which GI does not correspond to II exist in the cultivar of foods used for diet therapy of diabetes mellitus. We propose the addition of other information such as II and breath hydrogen excretion of selected foods.