British Coffee Association - Diabetes


Man in labType 1 diabetes, also sometimes known as ‘early onset’ or ‘juvenile’ diabetes, generally develops before the age of 40, usually during the teenage years. This form of diabetes is insulin dependent and cannot therefore be controlled by diet alone.

Type 2 diabetes is a condition that currently affects over one million people in the UK. Type 2 diabetes used to be called 'maturity onset' diabetes because it usually appears in middle-aged or elderly people, although it does occasionally occur in younger people. The main causes are that the body no longer responds normally to its own insulin (insulin resistance) and/or that the body does not produce enough insulin (pancreatic insulin deficiency). Type 2 diabetes may be controlled by diet alone or by diet in combination with medication.

Coffee and Diabetes

Coffee and caffeine have been studied in relation to both Type 1 and Type 2 diabetes and research is known to be ongoing. There is currently no evidence to suggest that individuals with diabetes need to avoid coffee.

Type 1 Diabetes

In relation to Type 1 diabetes, published research has shown that a modest amount of caffeine can increase awareness of the warning symptoms associated with the onset of a hypoglycaemic episode, and thus allow the patient to take action to avoid such an event 1.

Type 2 Diabetes

Published research has concluded that long-term coffee consumption is associated with a statistically significantly lower risk for Type 2 diabetes 2,3,4 and that coffee drinking has a graded inverse association with the risk of Type 2 diabetes 5. The mechanisms behind this are not clear at present, however, research conducted in the UK found that coffee drinking had an effect on two hormones in the body that control insulin secretion 6. Research into the relationship between coffee drinking and the development of Type 2 diabetes continues and many strong studies have been published which add considerable weight to this area of research 7,8.

A study published in Diabetologia in April, 2014, found increasing coffee consumption by more than one cup per day over a four year period lowered the risk of developing type 2 diabetes by 11% in the subsequent four years. Decreasing coffee intake by more than one cup per day may increase the risk of diabetes by 17%.9

In addition, the study found that consuming three or more cups of coffee per day lowered the risk of developing type 2 diabetes by 37%.9


Further research is needed to confirm the mechanisms of action involved in the potentially protective effect of coffee consumption against diabetes, though findings to date are very encouraging.

In addition coffee drinkers who have diabetes can continue to enjoy coffee confident in the knowledge that moderate coffee consumption, of four to five cups per day, can contribute to a healthy, balanced diet and may confer health benefits. Pregnant women should however moderate their intake following the guidelines issued by the Food Standards Agency, to 200mg caffeine per day from all sources.

1. Watson. Diabetes Care, Volume 23, 2000.
2. Van Dam R.M. et al. Coffee consumption and risk of type 2 diabetes mellitus. Lancet, 2002, 360:1477-1478.
3. Zhang Y. et al. Coffee consumption and the incidence of type 2 diabetes in men and women with normal glucose tolerance: The Strong Heart Study. Nutrition, Metabolism & Cardiovascular Diseases, 2011: 21(6):418-423.
4. Muley A. et al. Coffee to reduce risk of type-2 diabetes?: a systematic review. Current Diabetes Reviews, 2012; 8:162-168.
5. Tuomilehto. JAMA, Volume 291, 2004.
6. Johnston, Clifford & Morgan, American Journal of Clinical Nutrition, Volume 78, 2003.
7. Hiramatsu T. et al. Coffee consumption and serum-?-glutamyltransferase, and glucose tolerance status in middle-aged Japanese men. Clinical Chemistry and Laboratory Medicine, 2012; 25:1-7.
8. Wedick N.M. et al. Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trial. Nutrition Journal, 2011; 10:93.
9. Bhupathiraju, S. N. et al. Changes in coffee intake and subsequent risk of type 2 diabetes: three large cohorts of US men and women. Diabetologia, published online ahead of print, 2014.