Kava, a traditional herbal remedy made from the dried root of a South Pacific Island plant, helps relax the mind and improve thought processes, according to herbalist Ed Smith, a founding member of the American Herbalists Guild. In 2002, following European reports of liver failure and deaths due to kava consumption, the US Food and Drug Administration issued an advisory to consumers, warning of the risk for severe liver injury resulting from the use of supplements containing kava. Such injury, according to the FDA, may include hepatitis, liver failure or cirrhosis.
Traditional Kava Preparations Nontoxic
According to a 2003 review in "Toxicological Studies," even though kava is commonly consumed by natives where the plant grows, kava-related liver damage among these populations is practically nonexistent. Thus, traditional preparations containing only kava root appear to be relatively safe, and toxicity may be due to consumption of other parts of the plant. However, a 2003 report in the "European Journal of Gastroenterology and Hepatology" examined the cases of two "heavy kava drinkers" in New Caledonia who developed reversible liver injury despite their use of traditional preparations.
Aerial Kava Parts Contain Toxic Alkaloid
In 2003, scientists at the College of Tropical Agriculture and Human Resources in Hawaii demonstrated that the stems and leaves, but not the root, of the kava plant contain pipermethystine, an alkaloid that accounts for much of the plant's liver toxicity. These researchers also reported that European kava consumers who developed liver failure used supplements that contained peeled stems and leaves from kava.
Kava Interactions Contribute to Liver Problems
A 2010 "Annals of Hepatology" review reiterated the probable contribution of "poor kava raw material" as the cause of liver failure in many documented cases. However, the review's authors implicated risk factors for liver toxicity that applied to kava root preparations, inclluding overdose, heavy or prolonged use and the concomitant use of other herbal supplements or medications. The University of Maryland Medical Center warns that kava can interact with alcohol and with drugs used to treat Parkinson's disease, seizures, anxiety and some psychiatric disorders.
Considerations and Precautions
Although expert review of governmental reactions to reports of kava's toxicity showed a weak association between kava consumption and liver injury, not all of the questions regarding kava's safety have been definitively answered. Therefore, anyone who has liver disease should not use kava. If you use kava, you should avoid the concurrent use of alcohol. If you take prescription medications or other herbal supplements, do not use kava without first checking with your doctor. Until further information is forthcoming, you should not use kava for more than three months without taking a break. Use kava products that clearly indicate they contain only kava root or rhizome and limit your daily dosage to 200 mg of kavalactones from a standardized extract.
References
- "The Way of Herbs: Kava kava"; Michael Tierra, L.Ac., O.M.D.; 1998
- U.S. Food and Drug Administration Consumer Advisory: Kava-Containing Dietary Supplements May Be Associated with Severe Liver Injury; March 25, 2002
- "Toxicological Studies"; In Vitro Toxicity of Kava Alkaloid, Pipermethystine, in HepG2 Cells Compared to Kavalactones; P.V. Nerurkar, et al.; December 2003
- "European Journal of Gastroenterology and Hepatology"; Hepatic Injury Due to Traditional Aqueous Extracts of Kava Root in New Caledonia; S. Russman, et al.; September 2003
- "Annals of Hepatology"; Kava Hepatotoxicity -- A Clinical Review; R. Teschke; July 2010
- University of Maryland Medical Center: Possible Interactions with: Kava Kava
