Coffee is amongst the most widely consumed beverages in the world. Most of the evidence indicates a strong inverse association between coffee consumption and diabetes. Caffeine has been studied more than any other ingredient in coffee, but coffee contains many different substances. Some studies show caffeinated and decaffeinated coffee as having the same effect, which suggests that something else in coffee is responsible for its beneficial effects.

Physiological role of coffee on glucose metabolism

The health effects of coffee have been associated with its caffeine content. Caffeine has been shown to acutely reduce sensitivity to insulin[1], but also seems to have beneficial effects. Results of research suggest that an effect of coffee consumption on glucose metabolism is biologically plausible, and that the effects of coffee cannot be equated with those of caffeine.[2] Other bioactive ingredients of coffee are: chlorogenic acid and quinides, magnesium, lignans (are a group of chemical compounds found in plants) and other micronutrients (van Dam 2004). Table 1 shows a selection of coffee components and suggested mechanisms for effects of these components on glucose metabolism.[2]

Table 1.[2]

Component a Suggested mechanisms
Caffeine Reduced glucose storage through increased released of epinephrine or antagonism of the adenosine receptor
Increased expression of uncoupling proteins and lipid oxidation
Chlorogenic acids and quinides Antioxidant properties
Reduction of hepatic glucose output through inhibition of glucose-6-phosphatase
Effects on soft tissue mineral composition through action as a metal chelator
Reduction of intestinal glucose absorption through inhibition of glucose-6-phosphate translocase 1 and other mechanisms, and a subsequent increase in GLP-1 levels
Magnesium Cofactor for enzymes involved in phosphorylation that are essential for glucose metabolism; may affect insulin receptor activity through effects on hormone-receptor affinity or membrane viscosity
Lignans Antioxidant action and effects through binding of estrogen receptors, after conversion to enterodiol and enterolactone

[ a Reference provides information on the concentration of the component in coffee]

Clinical evidence for coffee and diabetes

Prevention of diabetes

The first study of coffee consumption and risk of type 2 diabetes was reported by Dutch researchers in the Lancet in 2002.[3] They prospectively investigated the association between coffee consumption and risk of clinical type 2 diabetes in a population-based cohort of 17,111 Dutch men and women aged 30–60 years. During 125,774 person years of follow-up, 306 new cases of type 2 diabetes were reported. After adjustment for potential confounders, individuals who drank at least seven cups of coffee a day were 0•50 (95% CI 0•35–0•72, p=0•0002) times as likely to develop type 2 diabetes as those who drank two cups or fewer a day.

In 2009 Huxley et al published a meta-analysis on the association of coffee and decaffeinated coffee consumption with risk of diabetes.[4] They found an inverse log-linear relationship between coffee consumption and subsequent risk of diabetes such that every additional cup of coffee consumed in a day was associated with a 7% reduction in the risk of diabetes after adjustment for potential confounders. Similar significant and inverse associations were observed with decaffeinated coffee and tea and risk of incident diabetes.

After this this meta-analysis, more studies have been published which confirmed the negative association for coffee consumption and type 2 diabetes with a dose response relation: lower incidence at higher consumption.[5][6][7][8][9][10][11][12][13]

Effects of coffee on diabetes related complications

Most studies refer to the role that coffee can play in the primary prevention of diabetes. There is some data on the possible influence of coffee consumption on the complications of diabetes.

Bidel et al did a large prospective study among almost 4000 Finnish patients with type 2 diabetes aged 25 to 74 years to assess the association between coffee consumption and CVD mortality among patients with type 2 diabetes.[14] During the average follow-up of 20.8 years, the respective multivariate-adjusted hazard ratios in participants who drank 0-2, 3-4, 5-6, and > or =7 cups of coffee daily were 1.00, 0.77, 0.68 and 0.70 for total mortality (P<0.001 for trend), 1.00, 0.79, 0.70 and 0.71 for CVD mortality (P=0.006 for trend), 1.00, 0.78, 0.70 and 0.63 for CHD mortality (p=0.01 for trend), and 1.00, 0.77, 0.64 and 0.90 for stroke mortality (p=0.12 for trend). They concluded that in type 2 diabetic patients coffee drinking is associated with reduced total, CVD and CHD mortality.

Zangh et al did two prospective cohort studies to investigated coffee consumption in relation to risk of CVDs and mortality in diabetic women and men.[15][16] These data indicate that regular coffee consumption is not associated with increased risk for CVD or mortality in diabetic women and men.

Conclusion and discussion

A number of studies demonstrate an association between (moderate) coffee consumption and reduced risk of developing type 2 diabetes and maybe the macrovascular complications of this disease. This can have implications in light of the already high and increasing prevalence of type 2 diabetes.

The choice of appropriate types of coffees may lead to benefits with regard to glucose metabolism while avoiding some of the potential detrimental health effects of coffee. Consumption of decaffeinated coffee may provide benefits for reduction of risk of type 2 diabetes while avoiding the detrimental effects of caffeine (for example reduced sleep quality).[2] Further knowledge on the effects of different coffee constituents on development of diabetes and its complications is necessary. The underlying mechanisms likewise need further investigation.


  1. ^ Keijzers GB, De Galan BE, Tack CJ, Smits P. Caffeine can decrease insulin sensitivity in humans. Diabetes Care 2002; 25: 364–69.

  2. ^ van Dam RM. Coffee and type 2 diabetes: from beans to beta-cells. Nutr Metab Cardiovasc Dis. 2006 Jan;16(1):69-77.

  3. ^ van Dam RM, Feskens EJ. Coffee consumption and risk of type 2 diabetes mellitus. Lancet. 2002 Nov 9;360(9344):1477-8.

  4. ^ Huxley R, Lee CM, Barzi F, Timmermeister L, Czernichow S, Perkovic V, Grobbee DE, Batty D, Woodward M. Coffee, decaffeinated coffee, and tea consumption in relation to incident type 2 diabetes mellitus: a systematic review with meta-analysis. Arch Intern Med. 2009 Dec 14;169(22):2053-63.

  5. ^ Zhang Y, Lee ET, Cowan LD, Fabsitz RR, Howard BV. Coffee consumption and the incidence of type 2 diabetes in men and women with normal glucose tolerance: the Strong Heart Study. Nutr Metab Cardiovasc Dis. 2011 Jun;21(6):418-23.

  6. ^ van Dieren S, Uiterwaal CS, van der Schouw YT, van der A DL, Boer JM, Spijkerman A, Grobbee DE, Beulens JW. Coffee and tea consumption and risk of type 2 diabetes. Diabetologia. 2009 Dec;52(12):2561-9.

  7. ^ Sartorelli DS, Fagherazzi G, Balkau B, Touillaud MS, Boutron-Ruault MC, de Lauzon-Guillain B, Clavel-Chapelon F. Differential effects of coffee on the risk of type 2 diabetes according to meal consumption in a French cohort of women: the E3N/EPIC cohort study. Am J Clin Nutr. 2010 Apr;91(4):1002-12.

  8. ^ Oba S, Nagata C, Nakamura K, Fujii K, Kawachi T, Takatsuka N, Shimizu H. Consumption of coffee, green tea, oolong tea, black tea, chocolate snacks and the caffeine content in relation to risk of diabetes in Japanese men and women. Br J Nutr. 2010 Feb;103(3):453-9.

  9. ^ Boggs DA, Rosenberg L, Ruiz-Narvaez EA, Palmer JR. Coffee, tea, and alcohol intake in relation to risk of type 2 diabetes in African American women. Am J Clin Nutr. 2010 Oct;92(4):960-6.

  10. ^ Bhupathiraju SN, Pan A, Malik VS, Manson JE, Willett WC, van Dam RM, Hu FB. Caffeinated and caffeine-free beverages and risk of type 2 diabetes. Am J Clin Nutr. 2013 Jan;97(1):155-66.

  11. ^ Hjellvik V, Tverdal A, Strøm H. Boiled coffee intake and subsequent risk for type 2 diabetes. Epidemiology. 2011 May;22(3):418-21.

  12. ^ Lin WY, Xaiver Pi-Sunyer F, Chen CC, Davidson LE, Liu CS, Li TC, Wu MF, Li CI, Chen W, Lin CC. Coffee consumption is inversely associated with type 2 diabetesin Chinese. Eur J Clin Invest. 2011 Jun;41(6):659-66.

  13. ^ Panagiotakos DB, Lionis C, Zeimbekis A, Makri K, Bountziouka V, Economou M, Vlachou I, Micheli M, Tsakountakis N, Metallinos G, Polychronopoulos E. Long-term, moderate coffee consumption is associated with lower prevalence of diabetes mellitus among elderly non-tea drinkers from the Mediterranean Islands (MEDIS Study). Rev Diabet Stud. 2007 Summer;4(2):105-11.

  14. ^ Bidel S, Hu G, Qiao Q, Jousilahti P, Antikainen R, Tuomilehto J. Coffee consumption and risk of total and cardiovascular mortality among patients with type 2 diabetes. Diabetologia. 2006 Nov;49(11):2618-26.

  15. ^ Zhang WL, Lopez-Garcia E, Li TY, Hu FB, van Dam RM. Coffee consumption and risk of cardiovascular events and all-cause mortality among women with type 2 diabetes. Diabetologia. 2009 May;52(5):810-7. doi: 10.1007/s00125-009-1311-1.

  16. ^ Zhang W, Lopez-Garcia E, Li TY, Hu FB, van Dam RM. Coffee consumption and risk of cardiovascular diseases and all-cause mortality among men with type 2 diabetes. Diabetes Care. 2009 Jun;32(6):1043-5.


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