Comments Provided to NTP Peer Review Panel on Green Tea Extract Toxicology Studies

26 May 2014 --- The American Herbal Products Association’s (AHPA) Chief Information Analyst, Merle Zimmermann, Ph.D., yesterday presented public oral comments, including those from the written comments submitted by the Council for Responsible Nutrition (CRN), at a meeting of the Technical Reports Peer Review Panel of the National Toxicology Program (NTP) to express significant concerns regarding a draft technical report on rodent studies conducted by NTP on the toxicology of a specific green tea (Camellia sinensis) extract.

Dr. Zimmermann noted that the draft report’s characterization of the tested extract did not include identification of the part of the plant used as a starting material, the solvents, or the preparation methods used to make the specific extract. He also testified that since there are many different and unique green tea extracts, NTP should make every effort to clarify that these studies are relevant only to the specific test article.

To support his position against extrapolating the results of these studies to other green tea extracts, Dr. Zimmermann informed the panel that a report issued last year by the Senate Appropriations Committee urged NTP “to be highly precise when describing the results of its studies on particular extracts of an herbal species to avoid any possible confusion about the relevance of such studies to other extracts of the species.”

Dr. Zimmermann also offered comments provided by Andrea Wong, Ph.D., vice president, scientific & regulatory affairs, CRN, in relation to contaminant testing, which was not reported as being conducted for residual solvents, microbiological contaminants, or polycyclic aromatic hydrocarbons.

Also noted in CRN’s comments was that the possibility should be considered that the observed effects on reproductive parameters were secondary alterations as a response to stress. In addition, CRN recommended there should be a discussion in the report on the observed protective effects from the study of green tea extracts against certain cancers.

During the meeting, several panel members requested additional information on the characteristics of the extract. Perhaps most importantly, the panel acted formally to downgrade the conclusions presented in the draft report to now reflect that there was “no evidence of carcinogenic activity” in either rats or mice, the only species assessed by the NTP.