Effects of dietary Polyphenols on Sugar Absorption and Digestion
One way to limit this glucose spike could be to inhibit the activity of digestive enzymes for glucose production and of the transporters responsible for glucose absorption.
It looks like Flavonols, Theaflavins, Gallate esters, 5-caffeoylqunic acid and proanthocyanidins inhibit α-amylase activity. Amylase is the enxyme that breaks down more complex sugars into glucose and maltose.
Recent results also suggest that plant polyphenolics like those found in Green Tea could help in this respect. Anthocyanidins and catechin oxidation products, such as theaflavins and theasinsensins, inhibit maltase; sucrase is less strongly inhibited but anthocyanidins seem somewhat effective. Lactase is inhibited by Green Tea catechins.
Once produced in the gut by digestion, glucose is absorbed by SGLT1 and GLUT2 transporters. Again this process can be inhibited by flavonols and flavonol glycosides, phlorizin and Green Tea catechins.
The above results have been supported by oral glucose tolerance tests on animals, and by human intervention studies on polyphenol-rich foods.
In conclusion, an intake of dietary polyphenols like those found in fruit, vegetable and other plants like Herbs, Spices and Green Tea could reduce diabetes risk.
Williamson G. School of Food Science and Nutrition, University of Leeds, UK.