Questions patients ask

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Q: What is the difference between type 1 and type 2 diabetes?

A: Both types of diabetes are characterized by high blood sugar levels, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced.

– Type 1 diabetes is a disease of the pancreas, which results in very little, or no insulin being produced. It is partly inherited and usually develops when the person is a child or young adult.

– Type 2 diabetes usually develops in adulthood and is primarily influenced by lifestyle factors such as poor diet, excessive alcohol consumption, smoking and lack of physical activity. In type 2 diabetes, the target tissues for insulin (muscle, liver and fat-tissue) become insensitive or resistant to the action of insulin. This means that more insulin is needed in order to maintain healthy blood sugar levels.

The association between coffee/caffeine consumption and diabetes is specific to type 2 diabetes only.

Q: Is coffee suitable for people with diabetes?

A: Yes, coffee is suitable for people with diabetes. According to scientific research, drinking moderate amounts of coffee does not have adverse effects for people with diabetes1

Q: Does coffee have any benefits for individuals with diabetes?

A: Research has shown that a modest amount of caffeine, equivalent to 2-3 cups of coffee per day, can make people with type 1 diabetes more aware that they are about to have a hypoglycaemic episode (low blood sugar)2,3. This ‘warning sign’ can help them to take preventative action.

Q: Can coffee lower the risk of diabetes?

A: Research suggests that drinking moderate amounts of coffee is linked to a reduced risk of developing type 2 diabetes; drinking 3-4 cups of coffee per day is associated with an approximately 25% lower risk of developing type 2 diabetes4-7.

Q: How much coffee do I need to drink to see a benefit?

A: Research has shown that drinking 3-4 cups of coffee per day is associated with an approximate 25% lower risk of developing type 2 diabetes4-7.

It is worth noting that the European Food Safety Authority (EFSA) concluded that caffeine intakes from all sources up to 400mg per day and single doses of 200mg do not raise safety concerns for adults in the general population. As one cup of coffee contains 75- 100mg caffeine, the observed association between 3-4 cups of coffee per day and a 25% reduction in diabetes risk is in line with advice from EFSA8.

Those sensitive to caffeine should check with their doctor or nurse to establish a level of consumption that is appropriate.

Q: Do all types of coffee have the same effect?

A: Both caffeinated and decaffeinated coffees have been linked to a lower risk of developing type 2 diabetes4,7.

Q: How does coffee reduce the risk of developing type 2 diabetes?

A: The simple answer is that we are not sure yet. Several hypotheses have been put forward and further research into the possible mechanism of action is currently being conducted.

Q: Are the suggested benefits of coffee down to caffeine?

A: Since decaffeinated coffee has similar effects to regular coffee, it is unlikely that caffeine plays a role. Other constituents of coffee, such as naturally occurring antioxidants, are currently being investigated to establish whether they contribute to the reduced risk of developing type 2 diabetes.


1Richardson T. et al. (2005) Influence of caffeine on frequency of hypoglycemia detected by continuous interstitial glucose monitoring system in patients with long-standing type 1 diabetes. Diab Care, 28:1316-1320.
2Debrah K. et al. (1996) Effect of caffeine on the recognition of and physiological responses to hypoglycaemia in insulin-dependent diabetes. Lancet, 347:19–24.
3Zaharieva D.P. and Riddell M.C. (2013) Caffeine and glucose homeostasis during rest and exercise in diabetes mellitus. Appl Physiol, Nutr & Metab, 38(8):813-822.
4Huxley R. et al. (2009) Coffee, Decaffeinated Coffee, and Tea Consumption in Relation to Incident Type 2 Diabetes Mellitus. Arch Int Med, 169:2053-2063.
5Jiang X. et al. (2014) Coffee and caffeine intake and incidence of type 2 diabetes mellitus: a meta-analysis of prospective studies. EJCN, 53(1):25-38.
6Ding M. et al. (2014) Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: A systematic review and dose response meta-analysis. Diab Care, 37(2):569-586.
7Santos R.M. (2016) Coffee consumption, obesity and type 2 diabetes: a mini review. Eur J Nutr, 55(4):1345-1358.
8EFSA (2015) Scientific Opinion on the Safety of Caffeine. EFSA Journal, 13(5):4102.

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