Although scientists are only at an early stage of understanding the way the gut “tastes” different types of food, University of Adelaide researchers are confident their findings will help patients manage their diabetes in the future.
The study, published in the journal Diabetes, described abnormal control of so-called “sweet taste receptors” in the human intestine for the first time. Its authors discovered that the way the gut senses sweet food may be defective in sufferers of type 2 diabetes, leading to problems with glucose uptake.
Dr Richard Young, senior postdoctoral researcher in the university’s Nerve-Gut Research Laboratory, explained that taste buds aren't the only way the body detects sweetness.
Flavour receptors all over the body
“When we talk about 'sweet taste', most people think of tasting sweet food on our tongue, but scientists have discovered that sweet taste receptors are present in a number of sites in the human body.
“We're now just beginning to understand the importance of the sweet taste receptors in the human intestine and what this means for sufferers of type 2 diabetes,” said Young.
In his study, he compared healthy adults to those with type 2 diabetes. He found that the control of sweet taste receptors in the intestine of the healthy adults enabled their bodies to effectively regulate glucose intake 30 minutes after exposure to the sugar. However, abnormalities among the diabetic adults led to a more rapid glucose uptake.
“When sweet taste receptors in the intestine detect glucose, they trigger a response that may regulate the way glucose is absorbed by the intestine. Our studies show that in diabetes patients, the glucose is absorbed more rapidly and in greater quantities than in healthy adults," continued Young.
“This shows that diabetes is not just a disorder of the pancreas and of insulin - the gut plays a bigger role than researchers have previously considered. This is because the body's own management of glucose uptake may rely on the actions of sweet taste receptors, and these appear to be abnormally controlled in people with type 2 diabetes."
Just the tip of the iceberg
However, more research is needed to better understand these mechanisms in the gut.
"So far, we've seen what happens in people 30 minutes after glucose is delivered to the intestine, but we also need to study what happens over the entire period of digestion.
“There are also questions about whether or not the body responds differently to artificial sweeteners compared with natural glucose," he says.
"By gaining a better understanding of how these mechanisms in the gut work, we hope that eventually this will assist to better manage or treat diabetes in the future."
This study has been funded by the National Health and Medical Research Council and Diabetes Australia. The results have been published online ahead of print in the international journal Diabetes.
Published ahead of print June, 12, 2013, doi:10.2337/db13-0581
“Disordered control of intestinal sweet taste receptor expression and glucose absorption in type 2 diabetes”
Authors: Richard L Young, Bridgette Chia, Nicole J Isaacs, Jing Ma, Joan Khoo, Tongzhi Wu, Michael Horowitz, and Christopher K Rayner