Cancer protection: regular or decaf?

In previous studies, green tea proved an effective cancer inhibitor in mice (SN: 8/31/91, p.133). Now, a group of researchers reports on the anticancer potential of green tea, black tea, and their decaffeinated versions. In female hairless mice, the caffeinated blends offer more protection against skin cancer, the team reports. In addition, black tea works as well as the green.

The findings, published in the July 1 Cancer Research, identify the antioxidant (-)-epigallocatechin gallate (EGCG) as the chief cancer fighter in green tea. As postulated in earlier studies, EGCG is believed to guard against tumors by attacking free radicals--highly reactive molecules or molecular fragments that can damage healthy DNA 

According to Zhi Y Wang of Rutgers University in Piscataway, N.J., all of the teas--green and black, regular and decaf--display antioxidant properties, though Wang believes too much focus has been placed on green tea, which contains more EGCG than black tea.

"We found black tea is comparable with green tea," Wang says. "We don't know why."

It may be, he theorizes, that the two teas share some important chemistry. Indeed, both are made from the same leaf. But in black tea, a fermentation process produces the stronger, woody flavor.

Wang says that black tea, though more chemically complex, should be studied further. Indeed, of the 2.5 million metric tons of tea produced worldwide, 78 percent is black tea.

Wang also says that the caffeinated teas have a light edge over decaffeinated versions in terms cancer protection.