Dairy consumption is associated with decreased insulin resistance among the Japanese.

Beneficial effects of dairy consumption in preventing obesity and metabolic syndrome have been suggested, but the association between dairy intake and insulin resistance (IR) is not clear. To test the hypothesis that higher dairy consumption is associated with lower insulin resistance, the authors investigated the association between dairy intake (taking fat content into consideration) and markers of IR in a Japanese working population. A cross-sectional study was conducted in 2009 among 496 subjects aged 20-68 years who participated in a health survey during a periodic checkup. Dairy consumption was assessed using a validated brief dietary history questionnaire. Multiple regression analysis was used to assess the association between fasting serum insulin, plasma glucose, and the homeostatic model assessment of IR (HOMA-IR) and dairy consumption with adjustment for potential confounding variables. The subjects in the highest quartile for total dairy intake showed the lowest mean IR markers compared to those in other categories, although the difference was not statistically significant. Intake of full-fat dairy products was inversely associated with HOMA-IR (P for trend = 0.02). The multivariable adjusted mean HOMA-IR values (with 95% confidence intervals) for the four groups, from those who consumed the fewest to those who consumed the most servings of full-fat dairy products, were 1.04 (0.96-1.12), 1.04 (0.96-1.13), 1.00 (0.91-1.08), and 0.86 (0.76-0.96), respectively. Low-fat dairy intake was not significantly associated with any IR markers. The results suggest that the consumption of full-fat dairy products may be associated with lower IR among Japanese adults.