AHPA chief science officer, Steven Dentali, said the summary of liver-related adverse events vindicated black cohosh because the herb best known to benefit women suffering from the symptoms of menopause, was not found in any of the six extenuating cases.
“The first step in making an association between any product and a reported adverse event must be to confirm the product’s identity,” Dentali said in a statement.
“Herbal manufacturers in compliance with current good manufacturing practice must ensure the identity of all ingredients and can therefore protect against inadvertent use of other cohosh species. This analysis by Health Canada has shown that authentic black cohosh was not involved in the cited cases, and calls into question all earlier adverse event reports purportedly associated with this herb.”
The AHPA was not available for further comment before publication.
Mark Blumenthal, founder & executive director of the American Botanical Council said no compelling evidence existed linking the herb to liver problems.
“…no hepatotoxic compounds are known to be present in black cohosh,” Blumenthal told NutraIngredients-USA.com, noting attention around the herb had grown since a HRT (hormone replacement therapy) trial was cancelled due to safety concerns.
“Around that time, probably in order to capitalize on the new black cohosh demand, other herbal materials were introduced into the market as ‘black cohosh’. This includes, but is probably not limited to, Chinese species in the genus Actaea, the same genus as black cohosh. Such plants are not true black cohosh.”
Verification
Those earlier events date from 1996 to 2002 and include another six adverse events, with Health Canada raising questions at the time about whether the supplements in question contained counterfeit material.
AHPA relayed that Health Canada’s 2002 assessment stated that, “details regarding verification of the herbal products taken by the individual” were not clear.
Therefore as there occurred such a “failure to authenticate the plant compounds in the preparations, one cannot establish that the herbs were the cause of the hepatotoxicity”.
Of the current batch, four were identified by Health Canada analysis as variations of Swiss Herbal-branded black cohosh (Actaea racemosa, formerly Cimicifuga racemosa) products, but containing other “related herbal species” other than black cohosh.
Two others were found not to be authorized on the Canadian market. The adverse events occurred between January, 2005 and March, 2009.
Due to such concerns, hepatotoxic label warnings are now required in countries such as the UK and Australia.
In the EU, the Committee on Herbal Medicinal Products (HMPC) of the European Medicines Agency (EMEA) identified three ‘possible’ and two ‘probable’ hepatotoxic cases out of 44 surveyed.
A subsequent review of these five adverse events found causality lacking in four of them, and no confirmation of black cohosh identity was determined.
Health Canada said it was “monitoring the situation”.
Health Canada considers a serious adverse event as: "a noxious and unintended response to a natural health product that occurs at any dose and that requires in-patient hospitalization or prolongation of existing hospitalization, that causes congenital malformation, that results in persistent or significant disability or incapacity, is life-threatening or results in death."
“…these domestic cases demonstrate that products not containing authentic black cohosh may be associated with liver adverse reactions.”