In the study, researchers followed more than 47,000 female nurses for several decades beginning in the 1970s. Every few years, the women answered detailed questions about their diets, including how much coffee, tea and cola (like Coca-Cola or Pepsi) they typically drank. Then the scientists looked at how many of the women were still alive and met their definition of “healthy ageing” in 2016.
Just over 3700 women met that definition: they were 70 or older; reported good physical and mental health, with no cognitive impairment or memory problems; and were free of 11 chronic diseases such as cancer, Type 2 diabetes, heart disease, kidney failure, Parkinson’s disease and multiple sclerosis.
The researchers found a correlation between how much caffeine the women typically drank (which was mostly from coffee) when they were between 45 and 60 years old and their likelihood of healthy ageing. After adjusting for other factors that could affect ageing, such as their overall diet, how much they exercised and whether they smoked, those who consumed the most caffeine (equivalent to nearly seven 8-ounce cups of coffee per day) had odds of healthy ageing that were 13% higher than those who consumed the least caffeine (equivalent to less than one cup per day).
Drinking tea or decaffeinated coffee was not associated with healthy ageing, the researchers found. That may be because the study participants generally consumed less tea and decaffeinated coffee overall, so perhaps there were fewer chances for the researchers to find benefits linked to them, said Sara Mahdavi, an adjunct professor of nutritional sciences at the University of Toronto who led the study. Tea and decaf coffee also have less caffeine, and tea has different plant compounds from regular coffee, so that may explain the results, too, she added.
Drinking cola, another potential source of caffeine, was associated with significantly decreased odds of healthy ageing.
Mahdavi cautioned that while drinking up to seven small cups of coffee per day was associated with healthy ageing in her study, that doesn’t necessarily mean that drinking that much will benefit everyone, or that it is healthy to do so.
Research in other groups of people suggests that the health benefits of coffee may plateau or even dip when they drink more than three to four cups per day.
What does other research suggest?
Many other studies have linked drinking coffee regularly to a lower risk of early death. In a study of more than 46,000 US adults published in May, Zhang and her colleagues found that those who consumed one to three cups of coffee per day were about 15% less likely to die within the next nine to 11 years than those who didn’t drink coffee. That benefit disappeared, though, for people who said they typically added more than about a half-teaspoon of sugar to their coffee and for people who added more than 1g of saturated fat (equivalent to about one tablespoon of half-and-half or 3.5 tablespoons of whole milk) per cup of coffee.
Research has also suggested that people who drink coffee regularly have lower risks of heart disease, Type 2 diabetes, Parkinson’s disease, liver disease, osteoporosis and some types of cancer.
These kinds of studies can’t prove cause and effect, said Aladdin Shadyab, an associate professor of public health and medicine at the University of California, San Diego.
But because the benefits associated with coffee have been so consistent, it’s unlikely that they are entirely explained by other aspects of a person’s life, Zhang said. If anything, drinking coffee is often associated with unhealthy habits, like smoking and less exercise. The fact that you see benefits after accounting for these differences means that coffee is probably helping, Zhang said.
How might coffee protect your health?
Researchers aren’t entirely sure why coffee may be beneficial. “It’s a bit of a mystery,” said Marilyn Cornelis, an associate professor of preventive medicine at Northwestern Feinberg School of Medicine.
Studies of mice have found that caffeine may improve memory and protect brain cells from damage. And human studies have found links between regular (not decaffeinated) coffee and a reduced risk of Parkinson’s disease.
Both regular and decaf coffee contain hundreds of chemical compounds, including many that may lower inflammation and prevent cell damage, Mahdavi said.
While the new study didn’t find a benefit associated with decaf coffee, other research has linked it, with regular coffee, to lower rates of Type 2 diabetes and other conditions, Cornelis said. Tea also contains many beneficial compounds, and drinking it has been associated with better heart health and a longer life.
What’s the takeaway?
If you drink coffee regularly, consider the new findings and others like it as good news that it may benefit your health – so long as you don’t add too much cream or sugar, Zhang said.
But if you don’t enjoy coffee, Mahdavi added, there’s no need to start drinking it. It can interfere with sleep or make some people feel anxious or jittery.
There are plenty of other, more evidence-backed ways to boost your health and longevity, Shadyab added, such as following a balanced diet, exercising regularly, getting enough sleep and having an active social life.
This article originally appeared in The New York Times.
Written by: Alice Callahan
©2025 THE NEW YORK TIMES
