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Mark A. Pereira, Ph.D., of Children's Hospital and Harvard Medical School, Boston, and colleagues examined the association between intake of dairy products and the incidence of insulin resistance syndrome (IRS). Components of IRS include obesity, glucose intolerance, high blood pressure, and blood lipid abnormalities (low levels of high-density lipoprotein, HDL, or ''good'' cholesterol and high triglyceride levels).

According to background information in the article, ''An increasing incidence of IRS in all racial, ethnic, and social class groups in the United States can be inferred from the increasing prevalence of obesity and type 2 diabetes over the last 3 decades. Recently, this syndrome has been observed in youth, and age-adjusted prevalence among adults has been estimated at 24 percent. An increase in the prevalence of IRS may partly explain the recent plateau or increase in cardiovascular disease rates, after several decades of decline.''

The researchers add that milk intake has decreased significantly over the past three decades while the prevalence of obesity and type 2 diabetes has increased. The authors state that for most of the past 30 years, the U.S. Department of Agriculture and the American Heart Association have recommended low-fat diets for the prevention and treatment of cardiovascular disease. The authors report that some other researchers have questioned these recommendations out of concern that high-carbohydrate consumption might promote IRS.

Dairy products were identified as any items reported during the diet history interview that were either 100 percent dairy (e.g., milk) or included dairy as one of the main ingredients. The most frequently consumed dairy product at the baseline examination was milk and milk drinks, followed by butter, cream, and cheeses.

''Dairy consumption was inversely associated with the incidence of all IRS components among individuals who were overweight but not among leaner individuals,'' the researchers report. ''The adjusted odds of developing IRS were 72 percent lower among overweight individuals in the highest [35 or more times per week] compared with the lowest [less than 10 times per week] category of dairy consumption. Each daily occasion of dairy consumption was associated with 21 percent lower odds of IRS. These associations were similar for blacks and whites and for men and women,'' the authors note.

''Our study suggests that dietary patterns characterized by increased dairy consumption may protect overweight individuals from the development of obesity and the IRS, which are key risk factors for type 2 diabetes and cardiovascular disease,'' the authors conclude.

Editor's Note: This work was supported by the Children's Hospital League, Charles H. Hood Foundation, a grant from the National Institute of Diabetes and Digestive and Kidney Diseases, an unrestricted gift from General Mills, Inc., and contracts from the National Heart, Lung, and Blood Institute (CARDIA).