Do the advantages and disadvantages of drinking coffee often lead to a longer life? Three cups of coffee a day can help prolong life?

Drinking three cups of coffee a day may help prolong life, according to a study of nearly 500000 people from 10 European countries.

The study, published in the Annals of Internal Medicine, shows that drinking an extra cup of coffee can prolong a person's life-even if it doesn't contain caffeine.

But skeptical experts point out that it is not necessarily because coffee has a protective effect, but that coffee drinkers may have a healthier lifestyle.

Researchers from the International Agency for Research on Cancer and Imperial College London say they have found that drinking more coffee is associated with a lower risk of death-especially heart and intestinal diseases. They reached their conclusions after analyzing data from healthy people over the age of 35 in 10 EU countries. At the beginning of the study, they asked them how much coffee they preferred to drink, and then looked at the average death toll of 16 years.

Professor David Spiegelhalter of the University of Cambridge analyzed public understanding of risk and said that if the estimated reduction in the death toll is really due to coffee, drinking an extra cup of coffee a day can extend a person's life by about three years. But despite the scale of the study, it is by no means perfect and accurate, nor does it prove that coffee beans are magical ingredients.

This is depressing news for coffee fans. That's because the study failed to take all factors into account-blurring people's certainty about the effect of coffee. For example, it does not take into account the life background of coffee drinkers compared with non-coffee drinkers. People who can buy three cups of coffee a day may be richer and the extra money helps protect their health to some extent. People who drink three cups of coffee a day may spend more time socializing, which in turn may increase their happiness.

So it seems that drinking coffee is good for the human body, isn't it? But in fact, some researchers pointed out that the more coffee they drank, the higher the incidence of ovarian cancer in women. Although the paper studied many people, the researchers excluded anyone who had diabetes, heart disease or stroke at the start of the study.

For many people, caffeinated drinks can temporarily make people feel more alert. But caffeine has a greater effect on some people than others, and the effect varies from person to person. NHS experts do not set limits on coffee in the general population, but they do say pregnant women should avoid drinking more than 200mg of caffeine a day. They say this is because coffee may increase the chances that babies will be born too young. Too much caffeine may also increase the risk of miscarriage.

And, of course, caffeine is not just in coffee. For example, the limit of 200 mg of caffeine can be achieved by drinking two cups of tea and a can of cola or two cups of instant coffee.

The strictest scientific way to determine that coffee can prolong life is to force thousands of people around the world to drink coffee regularly while preventing thousands of others from drinking it. Scientists will then have to monitor other aspects of their lives-for example, what else they eat and drink, how much money they earn and how much exercise they do. So this is a study that will never happen. Instead of wrestling with this problem, take the time to go to the coffee shop and order a cup of coffee. There is nothing wrong with walking, because I am exercising.