Good news for female coffee lovers
CHICAGO — Here's good news for women who love coffee: Drinking it doesn't seem to cause long-term high blood pressure, a study suggests.
But for some reason, women in the same study who drank colas did seem to have a greater risk of high blood pressure. Researchers were surprised at that and cautioned that the study wasn't conclusive.
Caffeine is a well-known ingredient in both beverages and has been shown to cause short-term increases in blood pressure. But coffee drinkers in the study were no more likely than abstainers to develop high blood pressure during 12 years of follow-up.
Previous data on coffee and hypertension are mixed, but there's a common perception that its temporary effects on blood pressure mean an increased long-term risk, said Dr. Wolfgang Winkelmayer, the study's lead author and a researcher at Boston's Brigham and Women's Hospital.
"We found strong evidence to refute" that belief, the researchers wrote.
There was even some evidence that women who drank lots of coffee — four or more daily cups of regular or decaf — faced a slightly lower risk for developing high blood pressure than those who drank little or none.
Winkelmayer said that may be because coffee has lots of antioxidants, which are thought to help protect the heart and reduce cancer risks.
He called the results for cola drinkers potentially worrisome, but also far from definitive because it's unclear how sodas might increase blood pressure.
The government-funded study appears in today's Journal of the American Medical Association.
Several recent studies have shown possible health benefits from coffee, including a report calling it a major food source for antioxidants; results linking heavy coffee consumption in men with a reduced risk of diabetes; and Japanese research suggesting that coffee might help prevent liver cancer.
Winkelmayer's group examined data on 155,594 mostly white female nurses age 55 on average who took part in two long-running health studies. They were questioned about their diets and health and followed over 12 years. About 33,000 were diagnosed with high blood pressure.
Women who drank more than three cups of coffee daily were about 7 percent to 12 percent less likely to develop high blood pressure than women who drank little or no coffee.
Those who drank at least four cans of sugared cola drinks daily had a 28 percent to 44 percent increased risk of high blood pressure, compared with women who drank few or none. Diet sodas also increased the risk, although slightly less than the nondiet drinks.