If you asked people years ago about the health benefits of coffee you would have gotten blank looks. Coffee was bad for your heart, wasn't it? Weren't there links to some types of cancer? If you were a kid, everyone knew that drinking it would stunt your growth. Right?
But several studies and what are called meta-analyses of studies have found some surprising ways that a couple of cups of coffee can help your health. A meta-analysis is a statistical method that pools all the data from several studies, which allows researchers to see patterns that were not apparent in the smaller studies.
Some of the results:
Based on 36 studies involving more than 1.2 million people, those who drank 3 to 5 cups of coffee a day were at the lowest risk for cardiovascular problems. People who drank more than 5 cups a day had no higher cardiovascular risk that those who drank none.
Eleven studies on more almost 480,000 participants found that drinking 2 to 6 cups of coffee a day was associated with a lower risk of stroke compared to those who drank no coffee.
Another meta-analysis found that drinking moderate amounts of coffee was associated with a lower risk of heart failure. Only those who drank more than 10 cups a day saw any increase in risk of heart failure.
A study looking at coffee consumption and all cancers seems to suggest that it might be associated with reduced overall cancer incidence.
A meta-analysis found that drinking two more cups of coffee a day was associated with a 40% lower relative risk of liver cancer.
It is not known how much of these protective effects of coffee are due to caffeine. Most of these studies did not look at decaf to see if it has the same protective effects as coffee with caffeine.
Make no mistake, though: there are downsides to coffee. Too much coffee can interfere with your sleep. If you drink your coffee with a lot of milk and sugar, you are adding a lot of calories to your daily intake. And most studies used an 8-ounce cup as a measure of how much coffee was consumed. So if you are filling your 20-ounce mug three times a day, you are actually drinking 7.5 cups a day.
And caffeine is an addictive substance. If you are used to drinking three cups a day and you stop suddenly you will go through withdrawal, with a bad headache and a lousy feeling for several days.
The bottom line is that if you don't have any sleep problems and don't feel jittery, enjoy your coffee.