Wednesday, March 19, 2008

Meta-analysis of glycemic index and glycemic load effects on chronic disease‏

Due to inconsistent findings from observational studies, there is controversy over the effects of dietary glycemic index (GI) and glycemic load (GL) on the risk of certain chronic diseases. A recent meta-analysis showed that diets high in GI and/or GL increase the risk of certain chronic, degenerative diseases.

The American Journal of Clinical Nutrition recently published a meta-analysis to evaluate the association between GI, GL, and chronic disease risk. A total of 37 prospective cohort studies of GI and GL and chronic disease risk were included. In 4 to 20 years of follow-up across studies, a total of 40,129 incident cases of degenerative diseases were identified.

For the comparison between the highest and lowest quantiles of GI and GL, significant positive associations were found for type 2 diabetes, coronary heart disease, gallbladder disease, breast cancer, and all diseases combined. Low-GI and/or low-GL diets are independently associated with a reduced risk of certain chronic diseases. Relating to cardiovascular disease and type 2 diabetes, the protection is similar with that seen in diets high in whole grains and fiber.

The findings support the hypothesis that higher GI and GL diets, and their resulting increases in postprandial (after meal) blood glucose levels, increase the risk of several chronic, degenerative diseases.

Source: Glycemic index, glycemic load, and chronic disease risk—a meta-analysis of observational studies, Barclay et al, American Journal of Clinical Nutrition, Vol. 87, No. 3, 627-637, March 2008