Effect of high milk and sugar-sweetened and non-caloric soft drink intake on insulin sensitivity after 6 months in overweight and obese adults: a randomized controlled trial.

Background/objectives: Milk contributes with saturated fat, but randomized controlled trials (RCT) on the effects of dairy on the risk of type 2 diabetes (T2D) where dairy is given as whole foods are scarce. The objective of our study was to investigate the long-term effects of semi-skimmed milk on insulin sensitivity and further to compare milk with sugar-sweetened soft drinks (SSSD).

Subjects/methods: A secondary analysis of a 6-month RCT with 60 overweight and obese subjects randomly assigned to 1 L/d of either milk (1.5 g fat/100 mL), SSSD, non-calorie soft drink (NCSD), or water was conducted. Insulin sensitivity was evaluated by oral glucose tolerance test (OGTT) and plasma free fatty acids. Second, fasting blood lipids, blood pressure, and concentration of plasminogen activator inhibitor-1 were assessed.

Results: There were no differences between milk, SSSD, NCSD, and water on insulin sensitivity assessed by OGTT (Matsuda Index, fasting, and area under the curve glucose, insulin and homeostasis model assessment values). SSSD increased total cholesterol compared to NCSD (P = 0.007), and triacylglycerol compared to NCSD and water (P = 0.045 and 0.045, respectively). None of the other parameters differed significantly between the groups.

Conclusions: In conclusion, there were no differences in effect between intake of milk, SSSD, NCSD, and water (1 L/d) for 6-month on risk markers of T2D in overweight and obese adults. As a secondary analysis, these results need confirmation in future studies.