Coffee consumption and type 2 diabetesPrint this page
Epidemiological studies suggest that drinking 3-4 cups of coffee per day is associated with an approximate 25% lower risk of developing type 2 diabetes, compared to consuming none or less than 2 cups per day1-19. Research also suggests a dose response relationship15-18.
A systematic review with a meta-analysis of 457,922 individuals and 21,897 newly-diagnosed cases of type 2 diabetes from eight different countries showed a statistically significant inverse association between coffee consumption and subsequent risk of type 2 diabetes2. The dose response analysis concluded that every additional cup of coffee, up to 6-8 cups per day, was associated with a 5-10% lower risk of developing type 2 diabetes. Drinking 3-4 cups of coffee per day was associated with an approximate 25% lower risk of developing type 2 diabetes, compared to consuming none or less than 2 cups per day.
A further meta-analysis published in 2018 with 1,185,210 participants and 53,018 incident T2D cases suggested that those in the highest category of coffee consumption (an average of 5 cups per day) had a 29% lower risk of type 2 diabetes compared with those who did not drink coffee. In addition, they concluded that the risk of type 2 diabetes decreased by 6% for each cup-per-day increase in coffee consumption18.
Additional epidemiological studies and reviews from different countries have also confirmed the inverse association with coffee consumption3-13, whilst a 10 year follow-up study from Greece also highlighted the significance of long-term habitual coffee drinking against diabetes onset14.
Further dose response studies have also been reported. A 2014 study concluded that participants who increased coffee intake by more than one cup per day over a 4 year period had an 11% lower risk of type 2 diabetes, whilst those who decreased coffee consumption by one cup per day had a 17% greater risk of type 2 diabetes15. A meta-analysis of prospective studies suggested a 12% reduction in risk of type 2 diabetes for every additional two cups of coffee per day, and a 14% reduction for every 200mg increment of caffeine per day. This review also suggested that the effect was stronger for women than men16. A 2014 systematic review and dose response analysis also concluded that the risk of diabetes was reduced by a percentage of, respectively: 8, 15, 21, 25, 29 and 33% for 1-6 cups of coffee per day17.
The effect of certain genetic polymorphisms on associations between coffee intake and type 2 diabetes was considered in a 2016 review, suggesting that the evidence for a reduced risk of type 2 diabetes in coffee drinkers may be limited when taking into account the genetic profile. These findings warrant further investigation25.
Research in a group of pre-diabetic patients concluded that diabetes progression was lowest in patients who drank black coffee three or more times per day. The study also considered the impact additions to coffee, such as creamer and sugar, had; and concluded that whilst the risk was lower for the patients who typically consumed black coffee than for those who mixed creamer and sugar into their coffees, the difference was not significant19.
A retrospective study, published in 2018, considered the effect of caffeine consumption in a group of patients with diabetes (both type 1 and type 2). The results suggested that caffeine from coffee was associated with a reduced all-cause mortality in women but not in men. The authors concluded that further research is required to understand the effect of caffeine consumption in men and women with diabetes in more detail26.
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