New Study Links 2 to 3 Cups of Coffee per Day to a Lower Risk of 3 Serious Health Conditions

A study published today in the Journal of Clinical Endocrinology & Metabolism¹ has linked drinking about two to three cups of coffee each day to a lower risk of developing heart disease, stroke, and type 2 diabetes.

“Coffee and caffeine consumption may play an important protective role in almost all phases of cardio-metabolic multi-morbidity development,” the study’s lead author, Chaofu Ke, told CNN. That’s when a person has at least two cardio-metabolic diseases (think: heart disease, stroke, diabetes, high blood pressure) at the same time.

Here’s what else the study says about caffeine’s role, including the possible effects of caffeine on heart health.

A closer look at the study

The research included 180,000 healthy people from the UK who did not have any cardio-metabolic diseases at the beginning of the study. Data was carefully analyzed from a large biomedical database that tracks people’s long-term health. Participants self-reported how much caffeine they drink, and the development of heart and metabolic disease was observed through hospital records, death certificates, and data from their primary care visits.

Researchers found that people who drank a moderate amount of caffeine had a significantly lower risk of heart and metabolic disease compared to people who didn’t drink coffee or drank less than one cup daily. Three cups of coffee a day (or about 200 to 300 milligrams of caffeine) was associated with a more than 40 percent reduced risk.

Given the huge sample size and comprehensive data, researchers (and even doctors unaffiliated with the study) feel confident about the results and, more generally, that caffeine may have a positive effect on heart and metabolic health.

“These observations add to the growing body of evidence that caffeine, and commonly consumed natural substances that contain caffeine such as tea and coffee, may enhance cardiovascular health,” Gregory Marcus, MD, the associate chief of cardiology for research and professor of medicine at the University of California, San Francisco, told CNN.

There are still questions about caffeine and heart health

The evidence is strong, but there’s more to be discovered about the connection between caffeine and heart and metabolic health (especially if you’re drinking too much coffee).

“It is important to emphasize that, while these data suggest a relationship between caffeine, tea, and coffee and a reduced risk of a combination of cardiovascular diseases, we need to be careful before we infer true causal effects,” Dr. Marcus says. “It remains possible that the apparent protective effects do not truly exist at all and that the positive associations are all explained by some as yet unknown or unmeasured true determining factor.”

The study did not factor in caffeine that comes from carbonated drinks or energy drinks, like soda or Celsius. So for now, there’s no way to tell if those caffeine sources would have the same positive effects, or whether coffee is the best type of caffeine for heart health, according to Ke.