The greater consumption of red meat over time has been linked to an increased risk of developing type 2 diabetes mellitus (T2DM) in a follow-up of three massive studies of American men and women.

Long has there been an association between the disease risk and an old-fashioned "meat and potatoes" diet, the meal's side dishes guilty merely by association. But now researchers have measured red meat consumption through time, among 149,000 study subjects.

Reporting on Monday in JAMA Internal Medicine, researchers from the National University of Singapore analyzed data from three large studies conducted by Harvard University, updating measurements of more than 26,000 men in the Health Professionals Follow-Up Study, nearly 49,000 women in the Nurses' Health Study and another 74,000 women in the Nurses' Health Study II.

The diets of study participants were assessed using questionnaires, accumulating a range of data encompassing 1.9 million person-years, wherein the disease occurred more than 7,500 times.

"Increasing red meat intake during a four-year interval was associated with an elevated risk of T2DM during the subsequent four years in each cohort," the study authors wrote.

Compared with those who consistently ate the same level of red meat, those who increased their consumption by more than a half-serving per day experienced a 48 percent higher risk of developing T2DM during the subsequent four-year period in the study. However, those who reduced their consumption of red meat by a half-serving per day from their baseline habit experienced a 14 percent lower risk during those years.

"Our results confirm the robustness of the association between red meat and T2DM and add further evidence that limiting red meat consumption over time confers benefits for T2DM prevention," the authors wrote.

They cautioned that causal results could not be conferred given the purely observational nature of the study.

William J. Evans, a researcher at Duke University and GlaxoSmithKline, said the study confirmed previous observations that the consumption of red meat is associated with the increased disease risk, but quibbled about the definition of red meat. "Perhaps a better description of the characteristics of the meat consumed with the greatest effect on risk is the saturated fatty acid (SFA) content rather than the amount of oxygen-carrying proteins," Evans wrote in commentary published by JAMA.

"A recommendation to consume less red meat may help to reduce the epidemic of T2DM," he wrote. "However, the overwhelming preponderance of molecular, cellular, clinical, and epidemiological evidence suggests that public health messages should be directed toward the consumption of high-quality protein that is low in total and saturated fat... These public health recommendations should include cuts of red meat that are also low in fat, along with fish, poultry and low-fat dairy products. It is not the type of protein (or meat) that is the problem: it is the type of fat."

Source: Pan A, Sun Q, Bernstein AM, et al. Changes In Red Meat Consumption And Subsequent Risk Of Type 2 Diabetes MellitusThree Cohorts Of US Men And Women. JAMA Internal Medicine. 2013.