We love our coffee, but often feel guilty when we reach for a third (or fourth). A recent large study suggests our guilt may be unfounded and that in fact, frequent coffee consumption – even eight cups per day – can improve our chances at living that little bit longer.

Coffee is hardly an under-researched subject, and with so many studies out there, it's difficult to make an informed decision. This is further complicated by the fact that our best data are from observational studies where people self-report via FFQs (food frequency questionnaires). That being said, this particular study was big (500,000 subjects), thorough (conducted using data collected over a 10 year period) and well managed, so the results are bound to be reassuring to many of us who are deeply committed to our daily brew.

Why do we need yet another study on coffee? It boils down to the inherent difficulty interpreting the results from observational, self-reporting studies. More data and better data analysis is always warranted.

"This new study is good, in my view" says Kevin McConway, Emeritus Professor of Applied Statistics at The Open University. "It's carefully performed and reported. It included over half a million people and was able to use reasonably detailed information on their coffee drinking, on various potentially relevant lifestyle factors and characteristics, and, interestingly, on certain genes that are known to affect the way caffeine is processed in the body. So it does help, to some extent, with investigating what it is about coffee drinking that might affect death rate."

Lead by Erikka Loftfield, a researcher at the US National Cancer Institute, the study used data from the UK Biobank and found those who drank coffee daily were up to 15 percent less likely to die than those who avoided it.

The study also showed positive trends for decaf drinkers too. Not as strong as for those who drank "real" coffee, but enough to suggest that other compounds, rather than caffeine, were at play. After all, coffee contains more than 1,000 chemical compounds and other research over the years has suggested compounds such as chlorogenic acid – which functions as an antioxidant – could be potent weapons against cell damage.

Loftfield's team also looked at coffee drinkers with common genetic polymorphisms that impair caffeine metabolism and found similar benefits to those without these issues.

Similar studies in the US have linked higher consumption of coffee to a lower risk of early death, while other studies have shown a daily coffee habit is also linked to a decreased risk of stroke and Type 2 diabetes. As for the old "coffee gives you cancer" line, the World Health Organisation took coffee off its list of possible carcinogens back in 2016.

So is your stove-top coffee pot some kind of fountain of youth? Not necessarily, but neither does it look like a fast-track to the grave. As for those looking for an excuse to drink even more coffee, well, nobody likes coffee-teeth do they?

The findings were published in the journal JAMA Internal Medicine.

Source: JAMA Network