Researchers fed green and black tea to diabetic rats for three months and then monitored the chemical composition of the rats' blood and eye lenses. At levels that would be equivalent to less than five cups of tea per day for a human, both teas significantly inhibited cataract formation relative to a control group which did not get tea, they say. The researchers found that both teas decreased glucose levels, which in turn affects other biochemical pathways that accelerate diabetic complications such as cataracts.
"Most people, scientists included, believe that green tea has more health benefits than black tea," says Joe Vinson, Ph.D., a chemist at the University of Scranton (Penn.) and lead author of the paper. In combination with Vinson's earlier research showing that green tea and black tea equally inhibit atherosclerosis — a major risk factor for heart disease — the findings suggest that both drinks could play a part in curbing two of the most widespread maladies in the United States today.
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Journal of Agricultural and Food Chemistry