Rice: a high or low glycemic index food?

We determined the glycemic (GI) and insulin-index (II) values for 12 rice products, using eight healthy subjects. The products were brown and white versions of three commercial varieties of rice [two varieties with normal amylose content (20%) and the other with 28% amylose], a waxy rice (0–2% amylose), a converted rice, a quick-cooking brown rice, puffed rice cakes, rice pasta, and rice bran. The GI of the rices ranged from 64 ± 9 to 93 ± 11, where glucose = 100. The high amylose rice gave a lower GI and II (P < 0.01) than did the normal-amylose and waxy-rice varieties. The converted rice and most other rice products gave a high GI. Insulin indices correlated positively with GI (r = 0.75, P < 0.05), although they were lower than expected. These results indicate that many varieties of rice, whether white, brown, or parboiled, should be classified as high GI foods. Only high-amylose varieties are potentially useful in low-GI diets.