Type II diabetes is epidemic worldwide where, because of problems with unsound nutritional and exercise habits, obesity is rampant and increasing. Obesity causes a loss of equilibrium in the body's use of insulin. Elsewhere in the developed world, diabetes is also increasing in incidence.

Diabetics suffer premature death from atheroselerosis and kidney failure. Blindness, amputation, and nerve damage also occur in diabetics at rates several times higher than non-diabetes.

The pathology in diabetes arises from a loss of balance in the metabolism of carbohydrates. Sugar is a carbohydrate, as are all forms of starchy foods.

Polysaccharides (long complex sugar molecules) consumed in the form of starch or complex sugars are digested by the enzymes amylase, maltase and sucrase. Amylase is present in saliva and is excreted by the pancreas into the small intestine, which produces maltase and sucrase. The end product of the digestion of these polysaccharides is glucose, the energy molecule used by all cells to power their activities.

Except through the effect of exercise, glucose cannot enter cells to be burned for energy without the presence of insulin. Insulin is a hormone produced and secreted by the pancreas. When sugar cannot be taken into cells to be burned it remains in the bloodstream in abnormaly high concentrations. These high concentrations of blood sugar have numerous damaging effects in the body and are often the indirect cause of the terrible multiple health problems that diabetes experience.

Obesity and/or the replacement of lean body mass with fat (as occurs naturally with aging), raises the amount of insulin needed to get glucose into the cells. Fat cells produce hormone-like substances that cause resistance to insuline (they also cause inflammation). As a result, an obese type II diabetic, even though their pancreas may be producing more insulin than a normal non-diabetic individual, will have insufficient insulin to remove the excess glucose from their bloodstream. Consequently, large amounts of glucose accumulate in the circulation, a condition called hyperglycemia. If carbohydrates can pass through the intestine without full digestion and complete absorption taking place, blood sugar can be lowered.

Both animal and human studies have demonstrated that consumption of catechins reduces the action of amylase and sucrase, two of the digestive enzymes used to break down polysaccharides into glucose.

In one study, the catechin epigallocatechingallate, or EGCG (found in the mangosteen), reduced the activity of the digestive enzyme alpha-amylase by 50 percent!

The effects upon amylase and sucrase in the studies were dose-dependent, meaning that, as the amount of catechin consumed increased, the blood sugar lowering effect became stronger. This effect of catechins on sugar metabolism also helps to explain the results of several other human and animal studies showing that the consumption of catechins can lead to substantial weight loss.