Since 2002, studies have been consistently highlighting a link between coffee consumption and a lower risk of developing type 2 diabetes. Subsequent meta-analyses have added even stronger evidence of this association.
So, although cause and effect has yet to be definitively proven with randomized control trials (RCTs) and the underlying physiological mechanism remains mysterious (the anti-inflammatory and/or antioxidant properties of coffee’s bioactive compounds are some of the current theorized top contenders), regular coffee drinkers have been able to happily justify their addiction for some time.
Indeed, the roasted seed (yes, seed) brew has been associated with a wealth of health benefits, including an overall longer lifespan and lower risks of several forms of cancer and dementia. And now, in case you needed more convincing, a new meta-analysis that compiled findings from 30 prospective cohorts comprised of 1.2 million participants shows that individuals who reported the heaviest coffee habit (highest bracket = a median 5 cups per day) had a 29 percent lower risk of developing type 2 diabetes (T2D) compared with those in the lowest bracket (median 0 cups/day).
The research, led by two scientists from the Karolinska Institutet, Sweden, and published in Nutrition Reviews, also provides additional backing to the theory that coffee’s protective effects stem from compounds other than caffeine, as people who reported drinking decaffeinated coffee beverages showed similarly reduced risks compared with those who drank very little to no coffee of any kind.
Moreover, while those who guzzle five or more servings had the lowest T2D risk, the authors found (as other groups have before) that coffee’s protective effect appears to be dose-dependent.
“Results for both caffeinated and decaffeinated coffee were available in 10 studies. Comparing the highest versus the lowest category, both caffeinated coffee consumption (RR [risk ratio] 0.73) and decaffeinated coffee consumption (RR, 0.80) were inversely associated with risk of T2D,” they wrote. The risk of T2D decreased, respectively, by 7% and 6% per cup-per-day increment of caffeinated and decaffeinated coffee consumption.”
As any good scientists would, the authors of the current meta-analysis list their work’s limitations and concede that RCTs are needed to prove the associations. It must also be noted that this particular investigation was partially funded by the Institute for Scientific Information on Coffee (ISIC), a non-profit dedicated to supporting research on coffee and health. The ISIC is backed by six of the largest European coffee companies: illycaffè, Jacobs Douwe Egberts, Lavazza, Nestlé, Paulig, and Tchibo.
At the end of the paper, a note states that “M.C. [author Mattias Carlstrom] has received funding from ISIC, which is a not-for-profit organization founded in 1990 and devoted to the study and disclosure of science related to coffee and health. The author assures that funding obtained from ISIC has not in any way affected the production or content of the current study.”
The institute’s annual report on coffee and diabetes – which includes this meta-analysis and other recent insights – was published on November 13, to coincide with World Diabetes Day.