Daily Pint of Milk May Lower Metabolic Syndrome Risk

CARDIFF, Wales, July 13 -- Men who drank at least a pint of milk daily were more than 60% less likely to develop metabolic syndrome than men who drank less milk, researchers reported here.

Moreover regular consumption of any dairy product reduced the risk of metabolic syndrome by 56%, but neither milk nor overall dairy product consumption significantly reduced the risk of new onset diabetes, reported Peter C. Elwood, M.D., of Cardiff University, and colleagues, in the August issue of the Journal of Epidemiology and Community Health.

The finding emerged from a study of 2,375 men who did not have diabetes at the time they were recruited for the Caerphilly Cohort Study (1979-1983). Men were 45 to 59 at baseline.

The risk of metabolic syndrome decreased as consumption of dairy products -- defined as milk, cheese, and yogurt -- increased so that men in the top quartile of dairy product consumption had an adjusted OR of 0.40 (95% CI 0.20-0.79), they wrote. Men who drank a pint or more of milk daily had a 0.38 OR for metabolic syndrome (95% CI 0.18-0.78).

About 15% of the men had metabolic syndrome at baseline, which was associated with a quadrupling of the 20-year relative risk of developing diabetes (RR 4.09, 95% CI 2.92-5.74), a 79% increase in relative risk of ischemic heart disease (RR 1.39 95% CI 1.36-2.37), and a 46% increase in relative risk of all death from any cause (RR 1.46, 95% CI 1.12-1.88), they wrote.

Food consumption was ascertained on the basis of a dietary questionnaires at baseline, which included specific questions about the quantity of milk and dairy products consumed daily. Additionally, 640 men kept a seven-day weighed dietary record.

Baseline examinations also measured plasma insulin, plasma glucose, body mass index, high-density lipoprotein and triglycerides, and blood pressure to identify men who had metabolic syndrome.

Metabolic syndrome was defined as the presence of two or more of these criteria:

• Plasma insulin of 163 mmol/L or more and/or plasma glucose of 6.1 mmol/L or more.
• BMI of 30 kg/m² or higher.
• HDL less than 0.92 mmol/L and/or triglycerides more than 3.25 mmol/L.
• Systolic pressure of 166 mm Hg or higher and/or diastolic pressure of 104 mmHg or higher.

At five-year intervals men were re-examined, self-reported diabetes was recorded, and incident vascular events were identified.

The authors conceded that the protective effect of dairy products they found could be explained by unmeasured confounding factors but "it seems most unlikely that a factor or factors further to those for which adjustments have been made could explain, let alone reverse, the trends observed."

Moreover, they said the findings were similar to those reported in the Tehran Lipid and Glucose Study and the CARDIA study. But the British Women's Heart and Health Study found that women who didn't drink milk had a reduced risk of metabolic syndrome.

Earlier this week, researchers from Tufts-New England Medical Center reported that dairy-rich diets, with high calcium and vitamin D intake, were associated with about a 30% reduction in risk of metabolic syndrome and about a 15% reduction in risk of diabetes. The diabetes risk reduction was only seen in those with glucose intolerance at baseline. (Dairy-Deficient Diet May Determine Diabetes Risk http://www.medpagetoday.com/Endocrinology/Diabetes/tb2/6130?pfc=101&spc=230)

U.S. dairy producers had been aggressively promoting dairy products as way to spur weight loss, but in May the Federal Trade Commission ruled that "such claims are not supported by scientific research." The FTC action came in response to a petition brought by Physicians for Responsible Medicine.