Coffee drinking linked to lower heart failure risk
Drinking up to four cups of coffee a day may reduce your risk of heart failure, a new study suggests. But the research also shows that people who drink 10 or more cups of coffee a day may be more at risk of having heart problems.
BMJ Group News
What do we know already?
Coffee is enjoyed by many people everyday all over the world. But we're not sure if drinking large amounts of coffee can cause health problems.
Some studies have looked at whether coffee drinkers have a higher risk of a heart condition called heart failure. This is when your heart isn't pumping blood around your body as well as it should. But these studies have found conflicting results.
One explanation for these inconsistent findings is that these studies have been fairly small or had other problems that made them less reliable.
To try to find out more about the link between coffee and heart failure, researchers pooled the results from five studies. A total of 140,220 people took part in these studies between 2001 and 2011, and 6,522 of them had heart failure.
The researchers looked at how likely people were to have heart failure depending on how many cups of coffee they drank every day. They defined moderate coffee consumption as four cups, and excessive consumption as 10 cups per day.
Drinking up to four cups of coffee a day was linked with a lower risk of heart failure. People who drank four cups of coffee a day were 11 percent less likely to have heart failure as those who didn't drink coffee.
Drinking less than this amount also reduced the risk of heart failure compared with people who drank none at all. But the reduction was not as big as for people who drank four cups a day.
However, drinking 10 or more cups of coffee a day was linked with an increased chance of heart failure. There was a slight increase of between one and three percent in the risk of heart failure in people who drank 10 or 11 cups of coffee a day compared to people who drank none.
How reliable is the research?
This is the first time that researchers have analysed all the good-quality long-term studies to see if there is a link between coffee drinking and heart failure. So the findings may be more reliable than previous studies.
Some of the people who took part in these studies already had a history of heart problems, or diabetes - which is linked to a higher risk of heart failure. The researchers took these factors into account when they looked at the relationship between drinking coffee and heart failure. But there may still have been other factors they overlooked.
These types of studies rely on people to report their coffee drinking habits accurately. But these may change over time. So we don't know for certain if there is a link between drinking a moderate amount of coffee and preventing heart problems.
Whether you drink strong or weak types of coffee, or caffeinated or decaffeinated coffee, may also affect your risk of having heart problems. But so far studies haven't looked at this.
What does this mean for me?
This study suggests that if you drink up to four cups of coffee a day you may have a lower risk of heart failure than someone who doesn't drink coffee. But there is not enough evidence from this study to show drinking a moderate amount of coffee will prevent heart failure. It is also not clear whether drinking 10 or more cups of coffee will make you more likely to have heart problems.
Other studies will need to explore the potential benefits and risks of drinking large amounts of coffee.
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