Kava Expert Says Toxicity Reports Likely Due to Poor-Quality Source Material

March 11, 2011

Several countries have banned products containing kava due to reported cases of liver toxicity associated with ingesting the herb.

Several countries have banned products containing the South Pacific herb kava (Piper methysticum G. Forster) due to reported cases of liver toxicity associated with ingesting the herb. However, the adverse effects may not be the result of kava itself but instead due to the poor-quality materials used in such products, says an expert in a review in the March issue of the American Herbal Products Association’s (AHPA; Silver Spring, MD) AHPA Report.

“Toxicity was associated with ingestion of traditional aqueous kava extracts, acetonic and ethanolic kava drugs, and kava dietary supplements in kava-herb mixtures,” wrote kava expert Rolf Teschke, MD, the review’s author. He said that reports of such toxicity contradict “the apparent safe, traditional use of kava for thousands of years.”

Countries may have banned kava products believing that toxicity is due to kava’s constituent kavalactones. However, said AHPA’s chief science officer Steven Dentali, PhD, “there isn’t enough information to say that the safety issue with kava is likely supposed toxicity associated with…kavalactones.”

He said that Teschke’s review “covers the host of hypothethical reasons for kava’s supposed toxicity, critically evaluating each one of the them, including the potential toxicity due to the possibility of mycotoxin contamination.”

In his review, Teschke pointed out that scientists and manufacturers should pay careful attention to the type of kava used, as well as to how that kava was harvested, handled, and processed, to ensure that the ingredient is of good quality and not contaminated. He noted that efforts have been made to improve kava quality standards and to enact stricter regulations for kava producers and manufacturers.

“Case reports can only serve as sentinel events,” Dentali commented. “In the absence of an immediate health hazard, an understanding of the materials involved, their chemical constituents, possible mechanisms of action, and other considerations are needed to properly evaluate sentinel events before bans are implemented against potentially useful remedies.”