Coffee's anti-diabetic properties could stem from its ability to inhibit a protein malformation behind Type 2 diabetes, Chinese researchers say.
Previous studies have shown that coffee drinkers are at a lower risk for developing Type 2 diabetes, which accounts for 90-95 percent of diabetes cases in the world. Those studies show that people who drink four or more cups of coffee daily have a 50 percent lower risk of Type 2 diabetes. And every additional cup of coffee brings another decrease in risk of almost 7 percent.
Scientists have also implicated the misfolding of a substance called human islet amyloid polypeptide (hIAPP) in causing Type 2 diabetes, and some are seeking ways to block that process.
Ling Zheng, Kun Huang and colleagues of the College of Life Sciences, Wuhan University, Wuhan, sought to find out whether coffee's beneficial effects might be due to substances that block hIAPP.
Protein folding is the process by which a protein structure assumes its functional shape or conformation. It is the physical process by which a polypeptide folds into its characteristic Amino acids interact with each other to produce a well-defined three-dimensional structure, the folded protein (the right hand side of the figure), known as the native state. Failure to fold into native structure produces inactive proteins that are usually toxic. Several neurodegenerative and other diseases are believed to result from the misfolded proteins.
In their paper published in the published in ACS' Journal of Agricultural & Food Chemistry, the researchers point out that coffee extracts have three major active components: caffeine, caffeic acid (CA), and chlorogenic acid (CGA).
And they sought to study the effects of these major coffee components, as well as dihydrocaffeic acid (DHCA), a major metabolite of CGA and CA.
Eventually the Chinese scientists found caffeic acid and chlorogenic acid significantly inhibited hIAPP. They suggest that this effect explains why coffee drinkers show a lower risk for developing diabetes. "A beneficial effect may thus be expected for a regular coffee drinker," the researchers conclude.