Coffee is the most popular morning drinks worldwide and has gained special interest in chronic diseases such as type two diabetes due to its influence on glucose metabolism. Caffeine has shown to:
● Increase plasma adiponectin concentration, a hormone secreted by the fat cells which exhibits insulin sensitizing and decreased insulin resistance [1], in addition to anti-inflammatory and antiatherogenic properties. (see figure1)
● Mediate the biologic effects of sex hormones (testosterone and estrogen) on peripheral tissues and glucose homeostasis [2].
● Acutely activate 5' adenosine monophosphate-activated protein kinase (5'AMPK) an enzyme that plays an important role in cellular energy homeostasis and insulin-independent glucose transport in skeletal muscle [3].
● Upregulate insulin-like growth factor 1 signaling, which in turn enhances insulin sensitivity on long term consumption.
What is its impact on type 2 Diabetes?
Coffee is a complex of multiple bioactive substances as caffeine, chlorogenic acid (CGA), and nutrients (minerals and vitamins). There is a dose-dependent and inverse association between consumption of coffee (both caffeinated and decaffeinated) or tea and risk of type 2 diabetes (T2DM). Decaffeinated coffee has been found to be also associated with lower hemoglobin A1c levels. (4)
Studies suggest drinking 3- 4 cups of coffee per day lowered the risk of developing T2DM by 25% compared to those consuming none or less than 2 cups per day. this implies to both caffeinated and decaffeinated coffee over weeks and with a follow up over 4 years. (5)
The bioactive compounds of coffee, CGA, was found to have antioxidant and anti-inflammatory effects that can lead to an improvement on glucose metabolism. Lack of information regarding other metabolic effects of other coffee constituents, even the type of roasting and brewing can play a role.
The suggested effect of reducing the risk of T2DM has only been shown on the long term (weeks). (5)
References:
1. Diabetes Care. 2008;31(3):504. Epub 2007 Dec 10
2. N Engl J Med. 2009;361(12):1152. Epub 2009 Aug 5
3. Metabolism. 2009;58(11):1609. Epub 2009 Jul 15
4. Diabetologia. 2009;52(5):810. Epub 2009 Mar 6
5. C.E.G. Reis et 190 al. / Journal of Traditional and Complementary Medicine 9 (2019) 184e191
