Study suggests that more than 4 cups of coffee a day could kill you

A recently published study by researchers at the Mayo Clinic suggests that more than four cups of coffee a day could be linked to an increased risk of premature death from multiple causes. According to National Public Radio, men under 55 who drink more than 28 cups of coffee per week had a 55 percent increased risk of death and women faced a greater than 200 percent increased risk of premature mortality.

The Mayo report, entitled "Association of Coffee Consumption With All-Cause and Cardiovascular Disease Mortality" was released last week and flies in the face of recent findings that suggest that coffee drinkers are at decreased risk of suicide, stroke and prostate cancer.

The threshold of risk, however, rises sharply for people under 55 who consume more that four cups a day.

"The older people, over 55, were not affected by these high amounts of coffee," said study co-author Dr. Chip Lavie to NPR.

Harvard School of Public Health epidemiologist Rob van Dam told NPR via email, "This result is surprising because results from other cohort studies in U.S. men and women suggest that coffee consumption is associated with a slightly lower risk of premature mortality."

The study looked at 40,000 subjects ages 20 to 87 who participated in the Aerobics Center Longitudinal Study, a long-term health study that ran from 1971 to 2002. One factor that could contribute to the risk of premature death for the heavy coffee drinkers appeared to be smoking. People who consumed more than four cups per day were often cigarette smokers, who face a number of health risks.

Harvard's Van Dam told NPR that since the studies began more than 40 years ago, many failed to take into account the link between coffee and smoking. Ultimately this led early researchers of the data to conclude that coffee was much more dangerous than it is, blaming it for the high blood pressure, heart disease and increased stroke risk seen in people who smoke.

Lavie told NPR's Maria Godoy that the bottom line is that drinking two to three cups of the brown stuff per day is harmless and potentially beneficial. Van Dam said that if a person is healthy, not a smoker and not pregnant, four cups of coffee a day does not pose any significant risk, according to "the totality of evidence."

However, he said, it's important to listen to your body's signals.

"If people think they experience detrimental symptoms related to too much caffeine, such as difficulty sleeping or nervousness," he said, "they should try reducing their intake."

[image of skeleton drinking poison coffee at his desk via Shutterstock.com]