I'm sure the folks at Starbucks are rejoicing at yesterday's headlines announcing that "coffee drinkers might live longer." Women who drank more than six cups of coffee a day were found to have a 17 percent lower risk of dying from heart disease, cancer, and other illnesses over 24 years of follow-up compared with those who drank less than one cup a month. My editor had a big smile on her face when she heard this news and happily told me that she downs eight cups of freshly brewed coffee every morning before she comes to work. Though I hate to burst her bubble, I have to point out that women who drank four to five cups per day actually had better protection: a 26 percent lower risk of dying.
Being a two-cup-a-day person myself, I think the findings of this study are more reassuring than life altering. The researchers carefully phrased their conclusion that "regular coffee consumption was not associated with an increased mortality rate" and that evidence of modest benefits needs to be studied further. Certainly, women shouldn't add coffee to their list of nutritious foods that they have to get more of. After all, male coffee drinkers in the study didn't enjoy a lower death rate, and too much caffeine can cause temporary increases in blood pressure—not good for those with hypertension or heart disease.
JoAnn Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital, agrees. "The evidence isn't up to the level where people should be encouraged to take up coffee drinking for the purpose of improving their health." She's one of the researchers on the Nurses' Health Study, which provided the data for the current study, and notes that it simply observed the lifestyle habits of people rather than randomly giving coffee to some and not to others. "It's quite possible that people who drink coffee regularly drink less of other beverages like sugar-sweetened sodas, so it's really open to question as to whether these are direct benefits from the coffee itself."
Pregnant women also need to be wary of how much coffee they drink. Studies have flip-flopped over whether caffeine can cause miscarriages, but one compelling finding that my colleague Ben Harder blogged about in January suggests that drinking as little as 200 milligrams of caffeine a day—equivalent to about two cups of brewed coffee—doubles the rate of miscarriages. Many experts advise pregnant women to abstain from coffee if they can or at least to limit consumption to about one cup a day.
But coffee certainly never earned its "sinful food" reputation either. A growing body of research has shown that, like tea, coffee packs a wallop of antioxidants that can protect against diseases like diabetes, Parkinson's, gallstones, and some cancers, as U.S. News previously reported. And an April study found that small amounts of caffeine could help counteract the increased Alzheimer's disease risk found in those with high cholesterol levels. Though caffeine has been linked to bone loss in elderly women, additional findings show that this poses a problem only for those who don't get enough calcium.
"I think the bottom line is that coffee is not deleterious to health and may even have some health benefits," Manson says. "For those who are regular coffee drinkers, that's good to know."