A synthetic version of the plant compound hydroxycitric acid (HCA) strongly delayed glucose absorption in rats suggesting that it could help regulate blood sugar levels in people at risk of diabetes, reports Dominique Patton.
HCA, extracted from a South Asian fruit called Garcinia cambogia, is already a popular food supplement in the US for weight loss and appetite control.
However the new research is thought to be first to show the supplement's effects on blood sugar control, which may explain the weight loss effects, say the Dutch researchers. Their findings also open up a new application area for supplement makers looking to help tackle the rise in type 2 diabetes.
Writing in the June issue of the American Journal of Physiology-Gastrointestinal and Liver Physiology, now online , researchers from the University of Groningen in the Netherlands said they administered HCA to a group of rats before mimicking a meal by infusing sugar into the stomach.
The synthetic supplement was supplied by HOB Ireland. It is a purer form of HCA (about 97 per cent) than most of the natural extracts marketed as supplements.
"Compared with controls, which had no HCA, the test rats' rise in blood sugar was much slower, but over 2.5 hours all the sugar was absorbed," explained lead author Peter Wielinga.
He told NutraIngredients.com that the glucose response was about 40 per cent lower in the rats, with sugar that is normally absorbed rather quickly - within about 20 minutes - taking over two hours after HCA ingestion.
"This delay is good because it reduces the high peaks of glucose, which otherwise would require the body to produce a lot of insulin to deal with the meal," he said.
"The good part is that although glucose absorption is delayed, the sugar is all absorbed. Presuming the supplement has the same effect in humans, the slower glucose absorption would lower insulin response and could slow down progression of type 2 diabetes," he added.
Wielinga noted however that the comparable dosage tested in rats is "probably way too high for humans" and that further tests would need to confirm the current findings in a human trial.
If clinical trials confirm the findings, the supplement may not only slow progression to diabetes but since people prone to the condition also often have an obesity problem, it could potentially have an additional benefit in the therapeutic field.
HCA has long been marketed for its weight loss effects and Wielinga believes that its action on blood sugar levels may account for much of the weight management benefits.
"The weight loss effect can be explained by HCA blocking the conversion of glucose to fat (the body stores extra glucose as fat if it is not used effectively)," he said.
"We also know that HCA reduces food intake. Our findings might suggest that the intestines remain full for a longer timer, leading to the satiety that prevents people from eating more," he said.
The team does not yet know why HCA affects glucose absorption. However the effects were observed after glucose was administered both into the stomach and into the small intestine. This, according to the researchers, excludes the possibility of a major effect of HCA on gastric emptying.
"It might have some effect on the glucose transporter in the intestines," said Wielinga.