The effect of amylose content on insulin and glucose responses to ingested rice.

We evaluated the effect of amylose and amylopectin content on the glucose and insulin responses to rice. Thirty-three normal volunteers were given three types of rice containing 0, 14 to 17, or 23 to 25% of carbohydrate in the form of amylose. The glucose and insulin responses were measured over a period of 180 min. Serum glucose response to high amylose rice was significantly lower at 30 min, and dropped more gradually by 180 min than with 0% amylose rice. In addition, the high amylose rice produced significantly lower insulin levels at 30 and 60 min, as well as lower integrated secretion over the 3-h test. Thus, our results suggest the presence of a factor in high-amylose rice which delays digestion and/or absorption of carbohydrate. Since fiber content and surface area of the test rices were identical, other factors must underlie these observed differences. These include differential enzymatic hydrolysis of amylose and amylopectin and the presence of lipid-starch complexes in the amylose-containing rice.