Why coffee could be good for your health

In the past, coffee was associated with increased health risks. But research from the last decade finds that drinking coffee may actually benefit your health.

Caffeine is the most popular psychoactive drug in the world. Humans have been drinking coffee, a natural source of caffeine, for centuries, but there have been mixed messages around its effect on human health for decades.

“Traditionally, coffee has been seen as a bad thing,” says Marc Gunter, professor of cancer epidemiology at Imperial College London and former head of the section of nutrition and metabolism at the International Agency for Research on Cancer (IARC). “Research from the 1980s and 90s concluded that people who drank coffee had a higher risk of cardiovascular disease – but it’s evolved since then.”

With more, larger-scale population studies emerging over the last decade, Gunter says, scientists now have data from hundreds of thousands of coffee-drinkers. But what does the research tell us – and is coffee consumption providing health benefits, or risks?

Coffee has been associated with an increased risk of cancer because it contains acrylamide, a carcinogenic substance found in foods including toast, cakes and chips. However, the IARC concluded in 2016 that coffee is not carcinogenic, unless it’s drunk very hot – above 65C (149F). In a 2023 review, researchers argue that, while coffee is one of the main sources of acrylamide in our diets, there is not yet a strong, conclusive evidence base showing that it relates to cancer risk.

The potential health benefits of drinking coffee

Not only that, but more research has found that coffee may actually have a protective effect. Some studies have shown an association between coffee drinking and a lower risk of some cancers in patients, for example.

In 2017, Gunter published the results of a study that looked at the coffee-drinking habits of half a million people across Europe over a period of 16 years. Those who drank more coffee had a lower risk of dying from heart disease, stroke and cancer. These findings are consistent with research from other parts of the world, including the US, and more recent research in the UK.

Gunter says there’s enough consensus across observational studies to confirm that people who drink up to four cups of coffee a day have fewer diseases compared to those who don’t drink any.

The potential benefit of coffee could go further. Coffee-drinkers in Gunter’s study were more likely to smoke and had unhealthier diets than non-coffee drinkers. This would suggest that if coffee does lower the risk of heart disease and cancer, it might be more powerful than we think – it’s overriding the effects of unhealthy behaviours.

That’s true whether it’s a cup of decaffeinated or caffeinated coffee. Decaf coffee has similar amounts of antioxidants as normal coffee, research has found. Gunter hasn’t found in his research any differences between the health of people who drank caffeinated versus decaf, which led him to conclude that the health benefits associated with coffee are due to something other than caffeine.

Why we can’t really know how coffee affects our health

However, all of this research was based on population data – which doesn’t confirm cause and effect.

People who consume coffee may simply have better underlying health than people who choose not to, says Peter Rogers, who studies the effects of caffeine on behaviour, mood, alertness and attention at the University of Bristol. That’s in spite of their unhealthier lifestyle habits, as found in Gunter’s research.

“Some people suggested there might be a protective effect, which is somewhat controversial as it’s based on population evidence,” he says.

Meanwhile, people who consume coffee regularly often have higher blood pressure, which should increase the risk of cardiovascular disease. But, Rogers says, there isn’t evidence that higher blood pressure from drinking coffee is associated with higher risk of cardiovascular disease.

Clinical trials looking into coffee – which could better determine its benefits and risks – are rarer than population studies. But a group of researchers conducted one trial in which they observed the effects of drinking caffeinated coffee on blood sugar.

The small study, conducted by the Centre for Nutrition Exercise and Metabolism at England’s University of Bath, looked at how coffee affects the body’s response to breakfast after a fragmented night’s sleep. They found that participants who drank coffee, followed by a sugary drink that stood in for breakfast, had a 50% increase in blood sugar, compared to when they didn’t consume coffee before “breakfast”.

Still, this kind of behaviour would have to happen repeatedly over time for the risk to accumulate.

Putting people into laboratory settings also brings up the question of how relevant the findings are to real life – indicating that neither population, or lab research can provide definitive answers on how coffee affects our health.