Drinking green tea with starch may blunt blood sugar spikes

November 20, 2012 in Diabetes & Diabetes Prevention, Nutrition Topics in the News

Drinking green tea with starch may blunt blood sugar spikes

An ingredient in green tea that helps reduce blood sugar spikes in mice may lead to new diet strategies for people, according to a study from Penn State University.

Mice fed an antioxidant found in green tea -- epigallocatechin-3-gallate (EGCG) -- and corn starch had a significant reduction in increase in their blood sugar -- blood glucose -- levels compared to mice that were not fed the compound.

The spike in blood glucose level is about 50 percent lower than the increase in the blood glucose level of mice that were not fed EGCG. The dose of EGCG fed to the mice was equivalent to about one and a half cups of green tea for a human.

The EGCG was most effective when the compound was fed to the mice simultaneously with corn starch. For humans, this may mean that green tea could help them control the typical blood sugar increases that are brought on when they eat starchy foods, like bread and bagels, that are often a part of typical breakfasts.

The EGCG had no significant effect on blood sugar spikes in mice that were fed glucose or maltose. The reason blood sugar spikes are reduced when the mice ate starch, but not these sugars, may be related to the way the body converts starch into sugar.

An enzyme called alpha-amylase that is produced in both the mouth and by the pancreas helps break down starch into maltose and glucose. EGCG may inhibit the enzymes ability to break down the starch, since the researchers also found that EGCG reduced the activity of alpha amylase in the pancreas by 34 percent.

If the mechanism holds in humans, this may mean that people who want to limit the blood sugar spike should skip adding sugar to their cup of green tea. Adding sugar to green tea might negate the effect that the green tea will have on limiting the rise in blood glucose level.

The researchers said the green tea and starchy food would need to be consumed simultaneously. For example, drinking a cup of tea well after eating a piece of toast would probably not change the blood sugar spike. The researchers' next step is to test the compound on people.

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