Let’s face it – Americans (among others), are hooked on coffee – it always good news when health benefits are found too. Research suggesting that there may be some potential health benefits to coffee continues to grow. One recent study found that those who sipped several cups every day had a decreased risk of developing multiple sclerosis. Another, published March 2 in the journal Heart, found that consuming three to five cups a day was associated with less calcium buildup in the arteries.

Ask the Expert: Coffee and Health

Dr. Rob van Dam
Assistant Professor in the Department of Nutrition, Harvard School of Public Health

4. Is there any research that suggests coffee may have some beneficial health effects?

Yes, research over the past few years suggests that coffee consumption may protect against type 2 diabetes, Parkinson’s disease, liver cancer, and liver cirrhosis. And our latest study on coffee and mortality found that people who regularly drank coffee actually had a somewhat lower risk of death from cardiovascular disease than those who rarely drank coffee; this result needs to be confirmed in further studies, however. This is a pretty active area of research right now, and it’s not at the stage where we would say, “Start drinking coffee to increase your health even if you don’t like it.” But I think the evidence is good that for people in general—outside of a few populations, such as pregnant women, or people who have trouble controlling their blood pressure or blood sugar—coffee is one of the good, healthy beverage choices.

5. Why does it seem like scientists keep flip-flopping on whether coffee is bad for you or good for you?

Often people think of coffee just as a vehicle for caffeine. But it’s actually a very complex beverage with hundreds and hundreds of different compounds in it. Since coffee contains so many different compounds, drinking coffee can lead to very diverse health outcomes. It can be good for some things and bad for some things, and that’s not necessarily flip-flopping or inconsistent. Few foods are good for everything. That’s why we do studies on very specific health effects—for example, studies of how coffee affects the risk of diabetes—but we also conduct studies such as this most recent one looking at coffee consumption and mortality over a long period of time, which better reflects the overall health effect.

Coffee is also a bit more complex to study than some other food items. Drinking coffee often goes along together with cigarette smoking, and with a lifestyle that’s not very health conscious. For example, people who drink lots of coffee tend to exercise less. They are less likely to use dietary supplements, and they tend to have a less healthful diet. So in the early studies on coffee and health, it was hard to separate the effects of coffee from the effects of smoking or other lifestyle choices.

Over the several decades that coffee has been studied, there have been some reports that coffee may increase the risk of certain cancers or the risk of heart disease. But in better conducted studies, such as the one we just published—larger studies that have a lot of information about all other lifestyle factors and make a real effort to control for these lifestyle factors—we do not find many of these health effects that people were afraid of.