Glycemie index — a review and implications for the Potato industry

Glycemic index (GI) ranks carbohydrate foods according to the postprandial impact on blood glucose. High glycemie index carbohydrates cause a rapid rise in blood glucose and are not recommended for consumption by diabetics, who have inadequate insulin production and are susceptible to hyperglycemia. The clinical value of glycemie index as a tool for controlling diet-induced glycemie response in diabetic patients is endorsed by the World Health Organization, the Canadian Diabetes Association, the European Association for the Study of Diabetes and the Dietitians Association of Australia. Currently the American Diabetes Association considers GI as primarily a tool for researchers. Potato is a carbohydrate food with no fat, rich in vitamin C and potassium and a good source of dietary fibre. However, the starch of cooked potato is rapidly broken down to glucose by amylolitic enzymes, resulting in a rapid elevation of blood glucose, and therefore potato products in general have a moderate to high GI. Glycemie load (GL) takes into account the actual amount of carbohydrate consumed per serving. The GL of potato is generally moderate and seldom high because of potato—s high moisture content. GI and GL provide useful guides for diabetics to control the glycemie response associated with the consumption of carbohydrate sources. GI and GL differ between cultivars and can be modified by processing methods. GI is also influenced by other components of the meal, even a previous meal. More research is required to adequately define GI and GL of potato cultivars and identify the impact of the composition of the starch (amylose/amylopectin ratio), processing techniques that contribute to a lower GI, and the effect of other meal components on the GI of potato.