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Coffee Consumption and Diabetes: The Final Word?

Nov 17, 2018
 
Editor: Joy Pape, MSN, FNP-C, CDE, WOCN, CFCN, FAADE

Author: Angela Reyes, Pharm.D. Candidate, LECOM College of Pharmacy

Conflicting data exists about the association between coffee consumption and its effects on blood glucose, insulin concentration, and risk of type 2 diabetes.

Those with diabetes have a lot of dietary recommendations to adhere to like little no refined carbohydrates, which can cause blood sugar to rise sharply. A dietary concern that can come up is coffee consumption among people with diabetes. Data is conflicting as to whether coffee is beneficial or harmful for those with diabetes. For example, a 2017 review from Diabetes & Metabolic Syndrome: Clinical Research & Reviews, found that five out of seven trials had results that caffeine increases blood glucose and keeps levels higher longer. However, some other studies show coffee has some benefits for people who have diabetes. In 2016, a study published in International Journal of Pharmacy and Pharmaceutical Sciences found coffee consumption led to lower uric acid levels. Uric acid has been linked to diabetes. Another study published in JAMA showed habitual coffee consumption was found to be associated with higher insulin sensitivity and lower risk for type 2 diabetes.

 

A recent systematic review examined all the current literature available on coffee consumption and diabetes. There were 24 trials that fit criteria for analysis. Studies were rated using the Jadad Score and a score less than 3 had a methodological weakness and was excluded for a total of eight studies being analyzed. Studies had various methods and were from multiple countries. Five studies were short-term and three were long-term studies. Six studies evaluated healthy lean individuals and one examined participants with excessive weight while another study examined people with type 2.

Among the short-term trials, there was a temporary impairment on the 2-3 hour postprandial glucose response after coffee ingestion. Overall, no significant differences were found in insulin concentrations and AUC, or insulin sensitivity. Also, no difference was found on glucose metabolism. In long-term studies, an improvement on glucose metabolism was seen. Among healthy and lean patients, data was mixed as to the effects of coffee consumption on insulin and glucose concentrations. Among overweight individuals, data showed mixed results as well.

In the one study using participants who had type 2, results found glucose 3-hour AUC was higher after coffee consumption than water. There was no difference in insulin AUC and insulin sensitivity. However, a recent meta-analysis found different results. Looking at 30 prospective studies, coffee consumption was inversely associated with type 2 diabetes risk.

According to the limited trials examined, short-term coffee consumption is not beneficial for glucose metabolism. Long-term coffee consumption did show improvement in glucose metabolism. This might be explained by other ingredients in coffee besides the caffeine that takes effect in the body after multiple ingestions. For example, coffee has polyphenols that have been shown to have antioxidant properties. This benefits the body and might lead to a protective effect of coffee. Current research is not at the point for a clear recommendation about coffee consumption in individuals with diabetes.

Practice Pearls:

  • Current data about coffee consumption among people who have diabetes show conflicting results.
  • According to this systematic study, short-term coffee consumption was associated with glucose impairment, but long-term effects of coffee consumption was beneficial.
  • More long-term studies are needed to make any concrete recommendations about coffee consumption and diabetes.

References:

Caio E.G.ReisJosé G.DóreaTeresa H.M.da Costa. Effects of coffee consumption on glucose metabolism: A systematic review of clinical trials. Journal of Traditional and Complementary Medicine. (2018) https://doi.org/10.1016/j.jtcme.2018.01.001

Carlström M1, Larsson SC2. Coffee consumption and reduced risk of developing type 2 diabetes: a systematic review with meta-analysis. Nutrition Rev. (2018);76(6):395-417. doi: 10.1093/nutrit/nuy014.

Angela Reyes, Pharm.D. Candidate, LECOM College of Pharmacy