Kava: Benefits and pitfalls
Dunya Tomic, Chief of Editorials and Publications PMSA
Kava (Piper methysticum) is a traditional plant that has been part of Pacific Islander culture for centuries. Originally used as a component of ceremonies, the demand for kava grew throughout the 20th century for its calming effects (1). With European arrival in the Pacific, kava became all the more sought after (2), initially in German herbal medicine regimes. In recent times, the herbal medicines industry has expanded greatly, and kava has become a phenomenon on a global scale.
As kava use spread across the Western world, this was a great economic asset to many Pacific countries, however the Westernization of kava has resulted in numerous issues arising. This is due to the fact that unlike the traditional kava plant used in the Pacific, which is made from the extract of powdered roots, Western kava typically comes in capsules containing acetone or dried ethanol extract. As a result, the majority of Western nations have banned kava products, due to the harmful effects of these ingredients on the liver. Reports of liver toxicity initially came from Europe but have extended globally including to Australia (3). Now that this major economic asset is no longer in production demand, the already struggling economy of many Pacific countries has become an even greater issue, which is expected to escalate over the coming years (4).
So what is the truth about kava? Currently, it is being heavily debated, especially regarding the reported hepatic concerns. Only the Western kava has ever had any severe liver toxicity reported. This has been poorly documented, however it is likely that ethanol and acetone-based kava may indeed cause severe liver toxicity, the rates of which have not been defined (5). For traditional Pacific kava, there have been no such concerns raised. However, other issues with traditional kava have been researched due to their significant use amongst the Indigenous Australian population, and it has been found to cause elevation in liver enzyme levels, particularly gamma-glutamyltransferase (GGT) (6). Although alcohol consumption is high amongst this cohort, which could potentially confound the results due to alcoholic liver disease being significantly linked to elevated GGT levels, the researchers ensured to take all precautions possible to ensure this confounding was minimalized.
Ultimately, the use of any therapeutic agent should be justified only if its benefits outweigh the potential risks. Although the adverse effects of kava may be rare, they are serious when they do occur. Furthermore, the actual benefits of kava are not well-established. Some argue that this liver toxicity should be tolerated due to the benefits of kava, much as is the case with benzodiazepines, which may also cause hepatic impairment (7). However, unlike benzodiazepines, which are well-supported in the literature, quality research into kava is minimal (8). Therefore, until further research is conducted into its true effects, kava use (or at least, Western kava use) should not be recommended. For Pacific countries to maintain the economic benefits of the product, research should be enhanced, and other alternatives such as exporting traditionally prepared kava to Western countries should be considered in the future.
References
Yadhu N, Singh Y. Kava: an overview. J Ethnopharmacol. 1992;37:13-45.
Lebot V, Merlin M, Lindstrom L. Kava. New Haven: Yale University Press, 1992.
Campo J, McNabb J, Perel J. Kava-induced fulminant hepatic failure. J Am Acad Child Adolesc Psychiatry. 2002;41:631-2.
Murray W. Neoliberal globalization, “exotic” agro-exports, and local change in the Pacific islands: a study of the Fijian kava sector. Singap J Trop Geogr. 2000;21:355-73.
Stevinson C, Huntley A, Ernst E. A systematic review of the safety of kava extract in the treatment of anxiety. Drug Safety. 2002;25:251-61.
Mathews JD, Riley MD, Feio L et al. Effects of heavy usage of kava on physical health: summary of a pilot survey in an Aboriginal community. Med J Aust. 1988;148:548-55.
Denham A, McIntyre M, Whitehouse J. Kava – the unfolding story: report of a work-in-progress. J Altern Complement Med. 2002;8:237-63.
Pittler MH, Ernst E. Kava extract for treating anxiety (Cochrane Review). In: The Cochrane Library. 2003; Issue 1. Oxford: Update Software.