“When the mixture is not too strong, the subject attains a state of happy unconcern, well-being and contentment, free of physical and psycological excitement. At the beginning conversation comes in a gentle, easy flow and hearing and sight are honed, becoming able to perceive subtle shades of sound and vision. Kava soothes temperaments.” – Louis Lewin 1927
Another herb story that exemplifies the complex often difficult path that traditional medicines travel in the modern world. Only some of which relates to the many and varied sciences that contribute to our understanding and recognition of them.
In this case a herb closer to home for me, the South Pacific pepper Piper methysticum, aka Kava or Awa.
A widespread and culturally significant plant consumed regularly by Pacific island people since well before European exploration and colonisation. This unique herb has however struggled for recognition globally since case reports of liver disease arose in Europe in the late 90’s and a rapid banning of it for human consumption in many developed countries has occurred during the early to mid 2000’s. Despite a rash of research and speculation on the causes and risks it is still unclear how many were really affected and by what, with numerous cases of concomitant use of liver toxins including pharmaceuticals and alcohol. However ongoing research continues to point towards some distinctly beneficial actions of Kava. Perhaps ironically in current circumstances, mostly in regard to the treatment of anxiety.
The genus Piper seems so distinctive, characteristic and yet minutely varied in detail from species to species. Found throughout the lowland tropical and subtropical rainforest lands of Asia, Africa, the Americas, Australia and W Pacific, there’s well over 1000 species recognised and it seems likely a few more that are yet to be resolved. The most commonly known product of these vines and shrubs is the fruit we call black pepper, Piper nigrum. With its own significance and importance in the history of western Europe since classical times. It was once worth almost the same as gold, today it is a cheap ubiquitous condiment on tables across the world.
Interestingly enough, it seems that P. methysticum is not one of those currently accepted names. In botanical speak its taxonomy and name is currently under review. Which is often the case with many of the more interesting and long cultivated plants that are of significant cultural interest to humans. It is not always easy to clearly delineate the species, their origin or relationships of different varieties or cultivars. This certainly seems to be the case with Kava, which cannot reproduce sexually and yet is found across Pacific islands as a bunch of distinctive cultivars and chemotypes. It seems most likely to be some sort of hybrid or sterile cultivar of P. wichmanii, which is found more in Papua New Guinea (the western and coastal or island provinces), the Solomon Islands and parts of Vanuatu. Only these two plants have been found to contain the active kavalactones. Though P. methysticum, the sterile cultivar, was ‘discovered’ and named by European botanists before P. wichmanii, the fertile wild type, creating some confusion that it seems is still unresolved.
Vanuatu is generally regarded as having the greatest range of Kava cultivars and is a likely epicentre of its distribution across the Pacific, making it as far as the Hawaiian islands before any European contact. It remains a major crop in Vanuatu, a significant cultural and economic plant. Though due to fears, the market for Kava in the UK and many other European countries dried up after bans were imposed in the early 2000’s. Kava seems to continue to be one of their largest agricultural crops though the government claims a 25% drop in export volume and significant reduction in markets from 2000 to 2010, primarily due to the bans imposed in the EU and elsewhere, including a ban on general public sale Australia in 2007.
It remains unclear what the issue really was with reports of liver damage and acute liver failure, with research focussing on type of extract solvent, part of the plant (roots or stems and leaves), concurrent alcohol or other drug use (prescription or otherwise), genetic susceptibility, metabolic polymorphism, overdosage etc. None of major constituents (kavalactones) or other reasons given above have been proven to induce hepatotoxicity. The age-old issue of poor quality and mouldy plant material containing aflatoxins appears a likely possibility not only for Kava, but is a risk for any poorly dried or stored plant materials including many human and animal plant foods. Aflatoxins are known to cause liver failure and in the longer term liver cancers.
Australia however also has a significant Pacific islander population and closer contact with the region and particularly countries such as New Zealand with a very large islander population. So Kava had been readily available and has been recognised as a culturally important product, a total ban on possession and use is unlikely to be enforceable here. There are ongoing campaigns from within some islander communities against the bans and limitations on Kava importation and use in Australia. It is not completely banned, individual importation of up to 2 kgs and personal use is legal, ostensibly for cultural reasons, however commercial or communal importation and social use or sharing is in effect illegal. The basis of islander Kava culture is in practice being repressed.
To a large extent the whole notion of legitimate social and cultural use of any plant drugs is still something that western contemporary societies can not tolerate or examine in any sensible way, despite it being a widespread phenomena in pretty much every human culture that has ever existed. This seems particularly so in contemporary Australia. Despite the often heard local idiom, no worries mate. When it comes to personal or social use of any ‘drug’ plants, some authorities are very worried and anxious to stop it.
In the case of Kava the campaign against it stems back to christian missionaries, as was the case for many culturally important plants around the world during early periods of European colonisation.
There has been some heated debate and controls tried on Kava in Aboriginal communities in northern Australia. Where the ravages of land and cultural dispossession, historical marginalisation, poverty and alcohol are also elements of the situation. It has been a ‘controversial’ debate that continues. Some communities developed a licencing system for Kava and its use grew during the 1990’s and 2000’s until the change in importation laws in 2007. It seems unclear how widely used or available Kava is currently in those communities.
What research was done on Aboriginal Kava use has almost entirely focussed on speculation of, mostly unproven, physical harms. Which even if they are present are insignificant compared to the physical damage from alcohol and particularly the violence stemming from its use. Same for the social harms, although it seems acknowledged even by detractors that Kava does actually reduce domestic and community violence levels.
Kava calms people rather than creating a drunken violent stupor.
It is no longer available legally for general consumption, but a black market developed during previous local bans. It remains unclear if this will simply increase the use and abuse of alcohol or other more destructive drugs. Even after research on the Aboriginal communities using Kava, in a more traditional manner as water extracts, there has been no reports identifying it as a cause of the liver failure in these communities, despite many other factors increasing their risks.
That was supposed to be just some background and only really scratches the surface of the complex Kava story so far.
For a detailed appraisal of the ethnobotany of Kava there’s no better book than Kava The Pacific Elixir by Vincent Lebot, Mark Merlin and Lamont Lindstrom. It was published in 1997 before the recent anxiety and bans imposed on Kava.
The last Cochrane review of Kava for anxiety was done in 2007, even then it was noted that there appeared to have never been a case of hepatotoxicity or severe adverse events in any clinical trials available. Which remains the case as far as I can see.
“The meta-analysis of seven trials suggests a significant treatment effect for the total score on the Hamilton Anxiety Scale in favour of kava extract.“
In the same year a World Health Organisation sponsored report (Assessment of the Risk of Hepatotoxicity With Kava Products) suggests there is still no current understanding of what might be a cause of hepatotoxicity, with insufficient evidence available to justify the bans on its use in some countries. More recent reviews (paywall) and commentary have further called for considering an end to the ban on Kava due to lack of evidence.
Of more recent interest has been a randomised controlled trial of Kava for anxiety in Australia. Where preparations derived of aqueous extracts with no more than 250mg kavalactones /day maximum dose are still available for use or prescription by herbalists and health practitioners. Due to Kava bans or warnings, clinical research has virtually stopped in many European countries and north America.
Published in 2009 was KADSS (paywall), the Kava Anxiety Depression Spectrum Study. They measured scores for both anxiety and depression using standardised scales in a crossover trial with groups receiving placebo then kava or kava then placebo respectively during the study. There’s no single standard pharmaceutical therapy for anxiety but antidepressants have often been applied.
In this study Kava not only significantly reduced the anxiety score of participants, it also significantly improved their concurrent depressive symptoms. Again without significant adverse events. The only other research they could cite in regard to Kava and depression was a report on a Kava extract improving state cheerfulness, according to the State-Trait Cheerfulness Inventory, apparently.
Despite a lack of clear evidence justifying a ban on Kava, there has been little movement from UK and other authorities to even consider the research, or centuries of widespread use amongst Pacific Islanders, in regard to restrictions on Kava trade. Traditional use of aqueous extracts exceeds the ‘therapeutic dose’ used in clinical trials by a significant margin.
Yet another interesting and intriguing herb, discovered by humans in pre-historical times, carried and cultivated by people as they explored their world. With a range of unique pharmacological actions that seem more useful than ever in our fast paced industrialised world of momentous changes. Which, despite our pretences to sophistication, we really don’t understand or know how to handle. So we ban it, hope it will go away?
Meanwhile the largest single cause of iatrogenic liver failure in humans is available to the general public as an over the counter medicine around most of the world, acetaminophen or paracetamol (Ibuprofen, Tylenol etc). Which is responsible for hundreds if not thousands of deaths and even more injuries due to liver trauma every year.
A whole month of posts in one this time. There’s been an enormous amount of research, reports and debate over this herb recently, more than I figured when I started this post. I’m sure we’ll hear more.