Glycemic Index (GI) Values for Major Sources of Dietary Carbohydrates in Iran

BACKGROUND: The glycemic index (GI) values of staple foods are not available in a standardized method in Iran. OBJECTIVES: The aim of this study was to measure the GI values of the major carbohydrate sources in a typical Iranian diet. METHODS: Using the international standard method, the GI values were determined for four wheat flatbreads, barley and rye bread, white and brown rice, as well as white and brown rice mixed with lentils. Twelve healthy adults were given 50 g anhydrous glucose three times (as the reference carbohydrate) and the test foods once each throughout the study. Using finger-prick blood samples, capillary blood glucose was measured using a reliable glucometer. The GI was calculated using the trapezoidal method. RESULTS: The GI values of the following types of bread were: Barley 66, Lavash 72, Taftoon 79, Sangak 82, rye 84, and Barbari 99. The GI values for brown and white rice were 65 and 71, respectively. The mixture of brown rice with lentils had a GI value of 55, and the mixture of white rice with lentils had a GI of 79. CONCLUSIONS: The most common types of bread and white rice consumed in Iran have high GI values. There is potential to reduce the overall GI values in the Iranian diet by encouraging the consumption of barley bread and brown rice.