Results from a study suggest that a low-glycemic diet — rich in foods containing carbohydrates that are slowly absorbed into the bloodstream — significantly lowered markers of inflammation and also increased a hormone that helps in regulating the metabolism of sugar and fat (1).
The study, published in the Journal of Nutrition, randomized 80 healthy men and women to a controlled feeding trial. Half of the participants were normal weight and half were overweight or obese. The researchers, from the Fred Hutchinson Cancer Research Center in Seattle, found through subjects’ blood samples that C-reactive protein, a biomarker of inflammation, was reduced by about 22 percent among the overweight and obese subjects who followed the low-glycemic diet.
“This finding is important and clinically useful since C-reactive protein is associated with an increased risk for many cancers as well as cardiovascular disease,” said lead author Marian Neuhouser, Ph.D., R.D. “Showing that a low-glycemic-load diet can improve health is important for the millions of Americans who are overweight or obese.”
The researchers also found among the overweight and obese subjects that a low-glycemic-load diet moderately increased levels of the protective protein hormone, adiponectin. Adiponectin improves insulin sensitivity and increases fatty acid oxidation.
For two 28-day feeding periods, completed in random order, the subjects ate a diet featuring high-glycemic-load carbohydrates, and then a diet featuring low-glycemic-load carbohydrates. The diets were designed to maintain weight and while the type of carbohydrate and amount of fiber differed, the overall amounts of carbohydrates, calories, and other nutrients were the same.
“Dietary patterns that rapidly increase blood glucose and insulin concentrations postprandially (i.e., high GL) not only stimulate insulin resistance but also induce an inflammatory response due to the acute excess of cellular glucose,” the authors wrote.
High-glycemic-load carbohydrate sources are usually low in fiber and include products made with white flour, sugar-sweetened drinks and desserts, as well as fruit in canned syrup. Low-glycemic carbohydrate sources are generally higher in fiber or protein and include whole-grains, kidney beans, pinto beans, lentils, milk, as well as fruits such as apples, oranges, grapefruits, and pears.
Reference
- Neuhouser ML, Schwarz Y, Wang C et al. A Low-Glycemic Load Diet Reduces Serum C-Reactive Protein and Modestly Increases Adiponectin in Overweight and Obese Adults. J Nutr 2011. doi: 10.3945/jn.111.149807
