A large analysis looked at hundreds of factors that might influence the risk of heart failure and found one dietary factor in particular that was associated with a lower risk：drinking coffee.
The analysis included extensive, decades-long data from three large health studies with 21, 361 participants, and used a method called machine learning that uses computers to find meaningful patterns in large amounts of data.
"Usually, researchers pick things that they suspect would be risk factors for heart failure - smoking, for example - and then look at smokers vs nonsmokers, " said the senior author, Dr. David P. Kao at the University of Colorado. "But machine learning identifies variables(变量) that are predictive of either increased or decreased risk, but that you haven't necessarily thought of. "
Using this technique, Dr. Kao and his colleagues found 204 variables that were associated with the risk of heart failure. Then they looked at the 41 strongest factors, which included smoking, blood pressure and the consumption of various foods. In all studies, coffee drinking was associated more strongly than any other dietary factor with a decreased long-term risk of heart failure.
Drinking a cup a day or less had zero effect, but two cups a day contributed to a 31 percent reduced risk, and three cups reduced the risk by 29 percent. There were not enough subjects who drank more than three cups daily to know if more coffee would decrease the risk further.
The study was not able to account for different types of coffee or brewing（冲泡）methods, or the use of additives like sugar or cream. Then should you start drinking coffee or increase the amount you already drink to reduce your risk of heart failure? "We don't know enough from the results of this study to recommend this," said Dr. Kao, adding that additional research would be needed.
