Using the Biobank study also allowed the researchers to examine a huge amount of genetic data, including that related to caffeine metabolism, which allowed for more robust analysis.
Last year, researchers in Spain also reported that people who drank at least four cups of coffee a day had a 64 percent lower risk of death than those who never or nearly never drank coffee. But the existing literature, including meta-analyses aggregating dozens of coffee studies involving millions of people, do show some notable associations between people who report drinking more coffee and protective effects against cardiovascular disease (the number one killer of Americans) like heart disease and stroke. About one-third of those surveyed said they drank between two and three cups of coffee each day, and 10,000 of them drank eight or more cups each day.
For the current study, the researchers analysed information provided by about 5,00,000 people, who answered questions about their coffee consumption, smoking and drinking habits, health history and more.
As with all studies like this in which researchers observe a group of people over time, this study can't prove that coffee is the cause of the reduced risk of death.
It seems like everyday there is a new study telling us either that coffee is slowly killing us or making us healthier.
However, the team behind the study stressed they only found a correlation between coffee and a lower chance of death.
People should also be aware that some people have a physical sensitivity to coffee.
Craving another cup of coffee?
And some of their habits and characteristics might make these British coffee-drinkers look unhealthier to start with. "Also, the women with the highest caffeine intakes were older, more likely to be poorly educated or obese prior to pregnancy, and to smoke during pregnancy".
It might reduce inflammation in the body, improve how insulin gets used, it might help liver function and it might benefit the linings of the blood vessels.
The research, which was published in the JAMA medical journal, states that over the 10-year study, 14,225 participants died. "This new study is consistent with the previous studies but show [s] that the potential benefit extends to higher intakes of coffee,"he said."But [it] doesn't mean that everyone should drink 8 cups of coffee a day".
When all causes of death were combined, even slow caffeine metabolisers had a longevity boost.