Eating slowly digested carbohydrates, such as whole grains, legumes and other high-fiber foods, milk and fruits significantly reduces markers of inflammation associated with chronic disease among overweight and obese adults, say researchers.
Such a "low-glycemic-load" diet, which does not cause blood-glucose levels to spike, also increases a hormone that helps regulate the metabolism of fat and sugar.
A new study by Fred Hutchinson Cancer Research Center, which involved 80 healthy Seattle-area men and women - half of normal weight and half overweight or obese - found that among overweight and obese study participants, a low-glycemic-load diet reduced a biomarker of inflammation called C-reactive protein by about 22 percent.
"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., a member of the Cancer Prevention Program in the Public Health Sciences Division at the Hutchinson Center.
Neuhouser and colleagues also found that among overweight and obese study participants, a low-glycemic-load diet modestly increased - by about 5 percent - blood levels of a protein hormone called adiponectin.
This hormone plays a key role in protecting against several cancers, including breast cancer, as well as metabolic disorders such as type-2 diabetes, nonalcoholic fatty liver disease and hardening of the arteries.
"Glycemic load" refers to how the intake of carbohydrates, adjusted for total grams of carbohydrate, affects blood-sugar levels.
"The bottom line is that when it comes to reducing markers of chronic-disease risk, not all carbohydrates are created equal. Quality matters," Neuhouser said.
"There are easy dietary changes people can make. Whenever possible, choose carbohydrates that are less likely to cause rapid spikes in blood glucose," she said.
These types of low-glycemic-load carbs include whole grains; legumes such as kidney beans, soy beans, pinto beans and lentils; milk; and fruits such as apples, oranges, grapefruit and pears.
Neuhouser also recommends avoiding high-glycemic-load carbohydrates that quickly raise blood glucose. These include highly processed foods that are full of white sugar and white flour, and sugar-sweetened beverages and breakfast cereals.
These findings are published online ahead of the February print issue of the Journal of Nutrition.