Research has linked green tea and its compounds to a number of potential health benefits, including preventing certain cancers and Type 2 diabetes. High blood sugar, or hyperglycemia, is a risk factor for diabetes -- and having diabetes also increases your chances of getting cancer.
A new animal study suggests that a compound found in green tea may reduce the spike in blood sugar that occurs after eating starchy foods. The study was published in the journal Molecular Nutrition & Food Research.
In the study, mice were placed on a corn starch diet to mimic what happens when humans eat starchy foods. The mice were then fed an antioxidant found in green tea called epigallocatechin-3-gallate (EGCG). The researchers found that, in mice given EGCG, the blood sugar spike that typically occurs after eating was significantly reduced (about 50% lower) compared to mice that were not fed the antioxidant.
If we were to drink the amount of EGCG given to these mice, it would be approximately the same as one and a half cups of green tea, according to the authors.
Interestingly, the EGCG didn't have much of an effect on the rise in blood sugar after mice were fed glucose or maltose, sugars broken down from starch. The authors say that an explanation for this probably stems from how the body converts and breaks down starch into sugars for energy. It seems that EGCG may be specifically interfering with that breakdown process, preventing starch from being turned into the sugar that eventually enters our bloodstream to cause blood sugar spikes.
The study suggests that this green tea effect is limited to starchy foods consumed simultaneously with green tea. Meaning that, drinking tea hours after eating a sleeve of crackers probably won't help reduce the rise in blood sugar that is bound to happen. Also, adding sugar to a cup of tea may actually eliminate the effect since table sugar is already in a simplified form that can readily enter the bloodstream.
Examples of starchy foods that can raise blood sugar include refined carbohydrates like white bread, white pasta, white potatoes, white rice and saltine crackers.
Maintaining a normal blood sugar level is important for health. Just as there are foods that can cause blood sugar to rise, there are also foods that can help lower or control blood sugar levels. The fiber in whole grains, such as whole wheat bread, oatmeal and brown rice, can help control and slow the release of sugar into the bloodstream. Beans, whole fruits, non-starchy vegetables, and lean protein can also help manage blood sugar.
The results from this study add to our knowledge of how green tea may interact with other components in our diet to influence our health. Research on humans, however, would be necessary to confirm the findings.