Researchers at the University at Buffalo and the University of Manitoba have found that the consumption of high amounts of low-fat dairy food decreased insulin resistance in healthy adults.
The high-dairy diet, though, had no ill effects on body weight, body composition, energy expenditure, blood pressure, blood glucose, blood lipid or lipoprotein responses.
“The study found that those who consumed four servings of dairy per day over a six-month period responded with a nine percent reduction in plasma insulin, and an 11 percent reduction in an established marker of insulin resistance,” said Todd Rideout, assistant professor of the department of exercise and nutrition sciences at UB School of Public Health and Health Professions.
The study evaluated 23 adults between the ages of 18 to 75, who were assessed to be healthy on a pre-study screening.
“They completed a randomized, crossover trial of 12 months,” Rideout said.
“Our study was designed to specifically examine the effects of low-fat milk and yogurt products. This is important, as different dairy foods have been shown to elicit differential metabolic responses. Determining the specific health benefits of specific dairy products and isolated dairy bioactive components will be critical issues of future dairy-based research,” he added.
The test subjects were first randomly assigned to one of two treatment groups: high-dairy group, which supplemented its diet with four servings of dairy a day (restricted to low-fat milk or yogurt products), or low-dairy group, which supplemented its diet with no more than two serving of low fat dairy each day. Subjects did this for a six-month period.
For the second six months of the study, the high-dairy and low-dairy diet groups swapped dairy products. The high-dairy group ate low-dairy, and low-dairy group ate high dairy. During both parts of the study, baseline, midpoint and endpoint metabolic responses were examined.
In HD-consumption groups, plasma insulin levels dropped by an average of nine percent, and insulin resistance was reduced by 11 percent when compared to the LD groups.
Metabolic syndrome or insulin-resistance syndrome is a combination of medical disorders that increases the risk of developing cardiovascular disease and diabetes. Twenty-five percent of Americans have the syndrome and its prevalence increases with age.
“Insulin resistance is a condition in which the body produces insulin, but does not use it effectively. When people have insulin resistance, glucose builds up in the blood instead of being absorbed by the cells, leading to type 2 diabetes or pre-diabetes,” wrote the Department of Heath and Human services.
While the exact causes of insulin resistance are not completely understood, scientists think the major contributors are excess weight and lack of physical activity.
For more information, the study is published in the May, 2013 issue of Nutrition Journal.