NIST Releases New Green Tea Standards


The health benefits of green tea remain largely undiscovered as researchers continue to announce encouraging findings. This week the National Institute of Standards and Technology (NIST) released a suite of green tea reference materials to help manufactures evaluate the composition of their products. The reference materials also assure researchers of the accuracy of analytical methods for studying the human health effects of both the beverage and dietary supplements.

The new SRMs (Standard Reference Materials) were prepared in collaboration with the National Institutes of Health Office of Dietary Supplements.
Green tea is rich in antioxidants, notably the phytochemical class "catechins," which some researchers believe account for its potential health benefits. “This has spurred interest in studying the chemistry of green tea and its extracts and in evaluating amounts of these antioxidant substances during and after the manufacture of green tea dietary supplements,” according to spokesperson Mark Esser.

“The NIST green tea SRMs are natural matrices, meaning they are derived directly from the plant,” he explains. “Unlike purified chemicals, reference materials of this type allows researchers to measure a well-known sample with all the chemical complexity of the natural product,” says Esser.

Using as many as five methods of analysis, NIST and collaborating laboratories have determined concentrations of seven catechins and gallic acid, three xanthine alkaloids (including caffeine), theanine, and toxic elements (arsenic, cadmium, lead and mercury) in SRMs 3254 Camellia sinensis (Green Tea) Leaves, 3255 Camellia sinensis (Green Tea) Extract, and SRM 3256 Green Tea-Containing Solid Oral Dosage Form.

These SRMs are the first green tea-containing reference materials with certified values for catechins. “It is anticipated that use of the reference materials will improve the measurement precision and accuracy of measurements of constituents in green tea products available as dietary supplements,” says Esser.

NIST prepares, analyzes and distributes more than 1,200 different carefully characterized materials that are used throughout the world to check the accuracy of instruments and test procedures used in manufacturing, clinical chemistry, environmental monitoring, electronics, criminal forensics and dozens of other fields. For more information, see NIST's SRM website.

SRMs 3254 through 3256 are available from NIST. See the Dietary Supplement Materials(includes nutraceuticals and herbs) for further information and to order.