The finding is one taken from a number of studies featured in the report, compiled by the Institute for Scientific Information on Coffee (ISIC), in which featured evidence points to coffee’s nutritional makeup as beneficial to health.
Whilst no firm conclusions are made, the roundtable representatives believe the growing body of research on coffee consumption and all-cause mortality was a matter that required further consideration.
“Data on cause of death and years lived combined with life expectancy data can be a useful way to understand the general population's health, and is research frequently examined by health organisations to help inform policy to guide people towards healthier diets and lifestyles,” said Sian Porter, spokesperson for the British Dietetic Association, UK and roundtable co-chair.
“The growing body of research on coffee consumption and all-cause mortality presents new data for consideration, although more evidence is needed to understand the association and mechanisms behind the results."
IARC research
Along with the meta-analyses that links coffee consumption with a 17% risk reduction of all-cause mortality, the report also highlights key research findings that include a study by Imperial College London and the International Agency for Research on Cancer (IARC), which found participants with the highest consumption of coffee, had a lower risk of all-causes of death.
Also included is a US study that found subjects who consumed a cup of coffee a day were 12% less likely to die compared to those who did not drink coffee.
Dr Robin Poole, specialty registrar in Public Health, Primary Care and Population Sciences Academic Unit at the University of Southampton, agreed with the report’s conclusions adding, “Unpublished data was discussed by some of the experts – the finer details of this unpublished work aren’t unavailable to critique, but these associations (but not causations) are reasonably well established.”
“Associations between drinking coffee and reduced risk of early death are from observational types of research, and there are confounding factors that could explain the associations.
“In other words, we still cannot say with certainty that for an individual drinking more coffee can lead to a longer life span – it could be something else such as income or other aspects of the diet which are responsible.”
Mechanisms of action
Evidence presented on coffee consumption and reduced all-cause mortality led the roundtable to discuss the potential mechanisms behind this association.
Roundtable co-chair Miguel Martínez-González, professor of nutrition at the University of Navarra, Spain, said the number of coffee’s compounds including caffeine, polyphenols, and the diterpenes cafestol and kahweol, made it difficult to identify one specific element to explain an effect.
Together with Dr Guiseppe Grosso, research fellow at the University Hospital Policlinico - Vittorio Emanuele, Professor Martínez-González suggested that caffeine was unlikely to explain the effect on mortality.
Equally significant was the potential role for polyphenols, such as chlorogenic acid, found in coffee, which may have antioxidant and anti-inflammatory effects.
Current food safety guidelines class 400 milligrams (mg) caffeine per day as safe for healthy adults, with single doses of caffeine of up to 200mg permitted. Pregnant women are advised to limit their caffeine intake to 200mg per day.
Can't recommend coffee....yet
“The report is a springboard to highlight the current level of scientific understanding around the link between drinking coffee and lower risk of dying from any cause,” said Dr Poole.
“The report was from a round table discussion of experts from a number of academic and clinical backgrounds and highlighted coffee being a credible component of a healthy diet.”
Dr Poole added that while the report hinted at being able to recommend coffee to patients at risk of type 2 diabetes and cardiovascular disease, the scientific community fell short of recommending people start to drink coffee, or increase intake, as a means of preventing specific diseases or living longer.
“I think existing evidence such as this serves to reassure those who are currently drinking moderate amounts of coffee that it can be enjoyed as part of a healthy diet.
“But some individuals are sensitive to the effects of caffeine, which for some can lead to headache, frequent urination and insomnia, and so these people are unlikely to tolerate increasing their intake,” he added.
“Finally the report highlights the need for further research into the associations especially into the mechanisms that might explain the potential benefit, and this also is entirely reasonable.”