Green Tea and Insulin Sensitivity
15 Times More Effective

A green tea and insulin sensitivity study found that it may benefit type 2 diabetes patients by raising insulin level.

Richard Anderson of BHNRC found that brewed tea, when added to the fat cells of laboratory rats, raises insulin activity by more than 15 times.

This higher insulin activity was found with green, oolong and black tea, regardless of whether caffeinated or decaffeinated.

In green tea and oolong tea, the catechin EGCG (epigallocatechin gallate) is largely responsible for the results. In black tea, active ingredients include tannins and theaflavins.

The rats were divided into three groups and over the course of 12 weeks and given either

  • Water,

  • A high fructose diet and water, or

  • The same high fructose diet but with green tea (0.5 gram of lyophilized green tea powder) instead of water

The group given fructose developed hyperglycemia, hyperinsulinemia, and elevated blood pressure. The green tea group showed improvement in all of these metabolic defects, and in insulin resistance and maintenance of normal blood pressure.

Interestingly, Anderson found that adding lemon to the tea did not affect the insulin-potentiating activity but adding 50 grams of milk decreased the activity by 90%.

The antioxidant property of EGCG is well known, but EGCG fights diabetes in another way.

It has been found that EGCG also works on the genetic level. It reduces the number of messenger RNAs, which tell liver cells to produce the sugar producing enzymes.

If you have diabetes, consult with your health adviser and use green tea cautiously. Green tea also contains caffeine, which may increase the blood sugar level.

Further research and studies can be found in Green Tea and Diabetes.

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Anderson RA, Polansky MM (2002). Tea enhances insulin activity . J Agric Food Chem 50:7182-7186.

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