Green Tea Supplements Fail Cancer Prevention Tests


WHITE PLAINS, NY -- announced results today of its Product Review of Supplements for Cancer Prevention. Among the products that selected for testing, quality problems were found with two out of five green tea supplements. The same was true of the selenium supplements reviewed. All lycopene supplements passed the review.

Cancer is the second leading cause of death in the U.S. Intake of certain foods, nutrients, and plant chemicals have been associated with reduced risk of cancer. Drinking green tea may reduce the risk of a variety of cancers and a supplement made of green tea extract has shown promise in reducing the rate of prostate cancer in men with a precancerous condition. A similar effect on prostate cancer risk has been found with lycopene supplements. Selenium may also provide a cancer-protective benefit, although perhaps only to individuals who are selenium deficient.

Supplements did not pass’s testing for a variety of reasons. Among green tea supplements selected for testing, one was contaminated with lead and provided less than its claimed amount of key compounds known as catechins. A daily dose of another green tea supplement provided 78.3 mg of caffeine (the amount in two cans of cola) although it claimed to contain less than 45 mg of caffeine. Caffeine occurs naturally in green tea, but it is possible to obtain extracts that have little caffeine – one product, for example, provided only 2.5 mg of caffeine per day.

Among selenium supplements, one failed to fully break apart in solution within the thirty minute USP requirement. Another selenium product claimed to include one gram of fiber per pill – an impossibility considering that each pill weighed less than 0.2 grams.

"Cancer prevention is an area where consumers need know the quality of the products they choose and the reason for choosing them," said Tod Cooperman, MD, President of "You won't know if your supplement lacks a key ingredients since you can't 'feel' a preventive therapy; and contamination is compounded when a supplement is used daily for years."

In addition to the fifteen products selected by, the report includes results for six products tested through its Voluntary Certification Program. Two other products are also listed as being similar to products that passed testing but sold under different brand names.

Products covered include those from Andrew Lessman (ProCaps), Carlson, Doctor’s A-Z, Douglas Laboratories, Food Science of Vermont, FREEDA, Futurebiotics, GNC, Jarrow Formulas, KAL, Karuna, MegaFood, Nature Made, Nature’s Bounty, Puritan’s Pride, Solgar, Spring Valley (Wal-Mart), Vitality Works, Vitamin Power, Vitamin World, and Whole Foods.

The new report is available here.


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