Tuesday, November 27, 2007

Higher Carb, Higher GI and High GL = Higher Risk for Diabetes

A study published in the November 26, 2007 edition of the Archives of Internal Medicine, Prospective Study of Dietary Carbohydrates, Glycemic Index, Glycemic Load, and Incidence of Type 2 Diabetes Mellitus in Middle-aged Chinese Women, reached a startling conclusion, "High intake of foods with a high glycemic index and glycemic load, especially rice, the main carbohydrate-contributing food in this population, may increase the risk of type 2 diabetes mellitus in Chinese women." [emphasis mine]

In the study, researchers reviewed the food consumption records of 64,227 Chinese women with no history of disbetes or chronic disease for 4.6-years. They conducted in-person interviews and collected data about dietary habits, exercise and lifestyle factors. Over the study period, 1,608 women developed diabetes (defined in the study as a fasting blood glucose greater than or equal to 126mg/dL.When the researchers analyzed the dietary habits they found the risk of diabetes was 78% higher in women consuming the most carbohydrate each day, with rice making up the largest portion of carbohydrate in this population of women.

As MedPage Today noted, "In a multivariate analysis, women in the highest quintile of carbohydrate intake had a 28% greater risk of diabetes compared with women in the lowest quintile (95% CI: 1.09 to 1.50). Women who consumed the most rice had a 78% greater risk of diabetes compared with women who had the lowest rice consumption (95% CI: 1.48 to 2.15)." [emphasis mine]

What is really interesting, at least from my perspective, is that the women in the lowest quintile ate a similar calorie load as those in the highest quintile - yet the diets of the two groups were vastly different with not only carbohydrate, but also protein and fat. The women with the lowest risk consumed an average 84g a day of protein and 43g of fat - the women with the highest risk consumed an average 60g of protein and just 22g of fat.

The carbohydrate intake of those found to have a high risk for developing diabetes wasn't shocking by American standards - 338g per day! Those in the lowest quintile consumed 22% less carbohydrate on average, or 264g a day. Another interesting tidbit from the study data - those consuming less carbohydrate actually had a higher intake of fiber - 13.8g versus 9.3g per day.