Lane, James D. “Caffeine, Glucose Metabolism, and Type 2 Diabetes.” JOURNAL OF CAFFEINE RESEARCH 1, no. 10.1089 (2011): 23-28, http://online.liebertpub.com/doi/pdfplus/10.1089/jcr.2010.0007 (accessed 13th April, 2013).
Hi everyone! The above is the reference to my first published paper on Caffeine, Glucose Metabolism and Type 2 Diabetes. I chose the topic of caffeine because I myself am a huge caffeine user, especially when it comes from French Vanilla coffee or Monster Energy Drink.
I also have it in my genetics to become diabetic due to all of my grandparents and some of my aunts and uncles having Type 2 Diabetes and I am curious to see if there is a link between the two. So the following is a summary of this journal article, which answered my question.
Type 2 Diabetes Mellitus is when insulin receptors in muscle, liver and fat cells become resistant to insulin, such that increasing the secretion of insulin by the pancreas does not overcome this resistance. Since insulin is responsible for the absorption of glucose into cells, the glucose levels in the blood increases and this is called hyperglycemia and results in Type 2 diabetes. It is believed that caffeine decreases the risk of diabetes. However, this review proves the opposite, where caffeine increases the risk of insulin resistance.
A study was carried out using both healthy and Type 2 diabetes individuals. Firstly, their glucose and insulin levels were measured under fasting conditions and then repeatedly after several hours of a standard dose of glucose administration. The healthy non-diabetic individuals showed an increase in blood glucose levels followed by an increase in insulin levels. After an hour or two, these levels dropped back down to the fasting values. When caffeine was ingested, insulin levels increased however there was no decrease in glucose levels. This proved that in healthy, non-diabetic individuals, caffeine produces an acute reduction in insulin sensitivity/ increased insulin resistance. Individuals who have Type 2 diabetes already have small insulin reserves and hence a small increase in carbohydrate can cause hyperglycemia. However, the same effect occurred when caffeine was ingested.
Although the exact mechanism on how caffeine affects glucose tolerance is not known, there are two hypotheses as to what may occur. Caffeine is an inhibitor to adenosine receptors (adenosine promotes sleep,) so the first hypothesis assumes that adenosine has some effect on insulin-mediated glucose transport and insulin responsiveness. The second hypothesis assumes that caffeine impairs glucose metabolism by the release of stress hormones (eg. Epinephrine and cortisol), which stimulate production of glucose in the liver and inhibiting insulin action.
Although these studies and experiments have proved that caffeine does indeed increase the risk of Type 2 diabetes, no body of evidence is without its weaknesses and limitations. Therefore, the results from the epidemiological studies that show the opposite must still be taken into account.