White Tea Extract: A Tea Less Processed
White tea is a rare tea produced almost exclusively in China and comes from the same plant (Camellia sinensis) as green and black teas. The descriptive term "white" comes from the high proportion of silvery buds on the plants, which impart a silvery color to the tea. White tea is the least processed of all teas, as it is picked then rapidly steamed and dried rather than fermented or roasted. Researchers believe this minimal processing of white tea yields a higher concentration of polyphenol antioxidants. White tea, in particular, offers high ORAC value.
White tea's primary benefit is as an antioxidant, squelching free radicals. Cancer risk is associated with free radical damage, and it is estimated that a deficient diet may account for as much as 35% of all human cancers. Researchers from the Linus Pauling Institute at Oregon State University (Corvallis, Ore.) have tested white tea's ability to protect bacteria from DNA damage and found white tea to be a much more powerful antimutagen than green tea.1 In additional studies at the Institute, rats fed white tea over an eight-week period, then exposed to the carcinogen PhIP, had significantly fewer PhIP-induced pre-cancerous lesions in the colon than the control.2 Both white tea and epigallocatechin-3-gallate (EGCG), which is found in high concentrations in white tea, have been shown to inhibit beta-catenin/Tcf activity. Beta-catenin and Tcf-4 are involved in the development of colorectal tumors.3
In addition, white tea has been researched as a topical agent, protecting against sun damage and boosting the immune function of skin cells.4 Scientists at University Hospitals of Cleveland and Case Western Reserve University (Cleveland) applied a white tea extract cream to one patch of skin on the subject's buttock (skin generally exposed to little sunlight), while another area was left unprotected. Both areas were exposed to artificial sunlight and the patches of skin were compared on a cellular level. The white tea extract protected the Langerhans cells, which were damaged in the sun-exposed skin. In the immune system, Langerhans cells are thought of as "watchdog cells," essential in detecting germs and mutated proteins produced by cancerous cells.
The investigators then tested whether the preserved immune system cells in the white tea extract-protected skin would still function properly after exposure to sunlight; they discovered the immune function was, indeed, restored by the extract. They also found that the DNA damage that can occur in cells after exposure to sunlight was limited in the skin cells protected by the white tea extract.
|What is ORAC?|
The ORAC (Oxygen Radical Absorbance Capacity) assay measures the ability of a substance to disarm oxygen-free radicals. The assay compares a sample to Trolox (a non-commercial, water-soluble derivative of tocopherol). Results are reported as mmoles Trolox Equivalents (TE)/g.
Single servings of fresh or freshly cooked fruits and vegetables supply an average of 600-800 ORAC units. Scientists believe that increasing intake of foods that provide 2000-5000 units per day may be needed to increase serum and tissue antioxidant activity sufficiently to improve health outcomes. The OxyPhyteâ„¢ white tea product from RFI Ingredients is part of a line of proprietary antioxidants made from GRAS ingredients selected for their antioxidant activity and high ORAC value.
References:1 Santana-Rios G, et al., 2001. Potent antimutagenic activity of white tea in comparison with green tea in the Salmonella assay. Mutat Res. 495: 61-74.
2 Santana-Rios G, et al., 2001. Inhibition by white tea of 2-amino-1-methyl-6-phenylimidazo[4, 5-b]pyridine-induced colonic aberrant crypts in the F344 rat. Nutr Cancer. 41(1-2): 98-103. Dashwood WM, et al., 2002. Inhibition of beta-catenin/Tcf activity by white tea, green tea, and epigallocatechin
3-gallate (EGCG): minor contribution of H2O2 at physiological relevant EGCG concentrations. Biochem Biophys Res Commun. 296(3): 584-8.
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