Glycemic index and glycemic load – a concept relevant for the diet of healthy individuals?

Part 1: Factors influencing the glycemic index, and relevance for the prevention of nutritional diseasesDeutsche Gesellschaft für Ernährung, Bonn

The glycemic index is a classification proposed to quantify the relative blood glucose response to carbohydrate containing foods. It is defined as the incremental area under the blood glucose response curve after a standard amount of carbohydrate from a test food relative to that of a control food is consumed.

Factors such as carbohydrate type and structure, other food components, the degree of processing and food preparation and the composition of the meal influence the GI and may have contributed to the large variation of published GI values for some foods, e. g. potatoes.

As both the quantity and quality of carbohydrate affect the glycemic response, the glycemic load (GL) has been defined. It is the product of the amount of available carbohydrate in a serving and the GI of the food.

Whether the GI is a predictor of the risk of developing prevalent chronic diseases has been the subject of several epidemiologic studies. In two of four large-scale cohort studies the GI or GL was unrelated to diabetes risk. In the other two studies, a low GI or GL was associated with a significantly reduced risk of developing type 2 diabetes. However, the association between GI and diabetes risk was attenuated by cereal fibre intake, in men to a greater extent than in women.

Study results are also inconsistent with regard to an association between GI and coronary heart disease. Furthermore, in the prospective Nurses’ Health Study and in a large case-control study, the relation between GI and coronary heart disease risk was modified by BMI. A low GI was only associated with a decreased risk of coronary heart disease in obese subjects (BMI ≥25) and in women with a BMI at or above 23.

Several studies have analysed whether the GI or GL of the diet is linked to the risk of cancer of the colon, pancreas, breast, endometrium or the ovaries. However, clear-cut results for the various cancer sites are missing and more research is clearly needed.

It has been suggested that low-GI foods promote satiety. However, short-term studies are difficult to compare because of methodological differences in measuring satiety and other differences among test diets. Whether low-GI foods prevent overeating and, in the long term, the development of obesity has not been systematically studied. EU03/04

Keywords: Glycemic index / glycemic load / diabetes / cancer / coronary heart disease / satiety

Sie finden den Artikel in deutscher Sprache in Ernährungs-Umschau 03/04 ab Seite 84.