Media outlets around the world are covering the release of a Harvard School of Public Health study stating that red meat consumption leads to an increased risk in mortality, stirring debate among the public and experts.

“It was beyond our expectation with so many debates being incurred, but we think it’s a good thing,” said An Pan, lead author of the study and research associate at HSPH. “We want more people to realize the potential health risks of eating too much meat.”

The data showed that one daily serving of unprocessed or processed red meat led to a 13 or 20 percent increase in mortality risk, respectively.

“We saw in this paper that [eating red meat] has implications, although the association is modest,” Pan said. “A 13 percent increase is not that high.”

The overall message was for people to try to reduce red meat consumption to two to three servings per week and to replace red meat with healthier choices, according to Pan.

Mortality risks of red meat consumption have been explored repeatedly, though not on the same scale as the 2012 study.

In 2009, for instance, researchers studied half a million people for three years and concluded that high intakes of processed and red meat may increase mortality risk.

Compared to previous research, the 2012 study surveyed a smaller cohort group for a longer period of time, nearly 25 years, and also distinguished between processed and unprocessed meats.

While earlier research focused on meat consumption’s effect on specific maladies, Pan’s study examined the broader impact on mortality.

The study took advantage of data from two long-term and well-known studies.

The Nurses’ Health Study, which began in 1976 to study breast cancer, was expanded to include a diverse population and to look at other health risks. It is widely regarded as one of the most prominent studies in diet and health, according to T. Colin Campbell, an emeritus professor at Cornell who studies nutrition.

“We realize this would be a good population to learn the long term effect on diet and health,” said Walter Willett, chair of the department of nutrition at HSPH who has overseen the study since its expansion in 1986.

The Health Professionals Follow-Up Study follows men ages 40 to 75.

The researchers designed standardized questions about health and have been updating their results every four years.

The study has been critiqued extensively by the expert community. One critique is that people who eat red meat tend to ignore common wisdoms of healthy behavior, creating correlating factors in their risks of mortality.

“This particular group doesn’t adequately acknowledge that,” said David E. Cummmings, a professor of medicine at the University of Washington. “They try to account for this but never fully.”

Willett acknowledged that the researchers cannot be sure to have taken into account all correlating factors.

The American Meat Institute issued a statement the day of publication responding to the study and criticizing its “unreliable self-reporting.”

“We were concerned that the study was quite definitive in its answer,” said Janet M. Riley, senior vice president of the American Meat Institute.

—Staff writer Kerry M. Flynn can be reached at kflynn@college.harvard.edu.