Kava isn’t only the best herbal answer for anxiety; it could also be the key to getting more quality shut-eye. Kava promotes healthy sleep, and typically doesn’t come with much of the ‘hangover’ effect you often get with sleep aids (although some users do report a mild after effect the following morning). There’s also clinical evidence to back this up. In a pilot, open-label study, patients suffering from stress induced insomnia were treated in each phase of six weeks with a daily dose of 120mg of a kava extract standardised to 30% kava lactones, then valerian extract at 600mg, then the combination of kava and valerian, with a two week washout period between each treatment phase.1,2
Get more ZZZs with kava
Total stress severity was significantly relieved by the kava and valerian single treatments (p<0.01), as measured in three areas: social, personal and life events. Insomnia was significantly relieved by the combination of kava and valerian (p<0.05)1 and the individual treatments (p<0.01).2 On direct questioning, 16 patients (67%) reported no side effects while on kava, versus 10 (53%) for valerian and 10 (53%) for the combination. The most common reported side effects were vivid dreams with kava plus valerian (four cases [21%]) and with valerian alone (three cases [16%]), followed by gastric discomfort and dizziness with kava (three cases each [3%]).1 The dose of kava lactones used in the trial was relatively low, and the results are limited by the lack of a placebo group.
Axe the anxiety and get more quality shut-eye
A randomised, placebo controlled, double-blind, multicentre clinical trial assessed the use of a kava extract in sleep disturbances that were associated with anxiety disorders in 61 patients. A more robust dose of kava extract of 200mg/day (containing 140mg kava lactones) was used over a period of four weeks. Using a sleep questionnaire on ‘Quality of sleep’ and ‘Recuperative effect after sleep’ the kava group was shown to have had statistical improvements (p=0.007 and p=0.018, respectively). Volunteers were also able to independently confirm that the kava worked better than the placebo through the use of a self-rating scale of well-being, the clinical global impression (CGI) and the HAMA psychic anxiety sub-score (p=0.002).3
A 2005 review of medicinal plants for insomnia suggested that kava “… is a well-established hypnotic drug, with a rapid onset of effect, adequate duration of action and minimal morning aftereffects.”4 However, concerns were expressed over hepatotoxicity.
Exposing liver damage rumours to the light
So what’s the real story behind kava hepatotoxicity? Step in Professor Rolf Teschke, a liver specialist, who has written extensively on this topic in conjunction with several different collaborators. Essentially, there are two theories in play: either kava rarely but directly causes DILI (drug-induced liver injury), or the liver damage potentially due to kava is caused by contaminants that are toxic to the liver. On this, Teschke, Sarris and Dr Vincent Lebot (an expert on kava from Vanuatu) recently wrote:
“The culprit of kava hepatotoxicity will continue to remain a mystery in humans, if the underlying reaction is of idiosyncratic, unpredictable, and dose-independent nature due potentially to some metabolic aberration in a few individuals emerging from kava use. In addition, kava hepatotoxicity is presently not reproducible experimentally in preclinical models, as demonstrated by studies showing whole kava extracts are not hepatotoxic. This led us to propose our ‘working hypothesis’ that contaminant hepatotoxins including moulds might have caused rare kava hepatotoxicity in humans. Further studies are now warranted to prove or disprove our working hypothesis, because kava hepatotoxicity possibly based on contaminant hepatotoxins could be a preventable disease. In the meantime, however, for minimising toxicity risk in kava users, a pragmatic approach should focus on the medicinal use of an aqueous extract derived from peeled rhizomes and roots of a non-mouldy noble kava cultivar, limited to maximum 250mg kava lactones daily for acute or intermittent use.”5
‘Noble kava cultivar’ here refers to a variety of kava that has been traditionally used and developed over a considerable time in the Pacific islands and is regarded as safe. Kava is not grown from seed; the plant is propagated from other living kava plants. If a cultivar was found to cause side effects, it was discarded in favour of ones that did not. This process of selecting and breeding kava cultivars into noble ones has taken many hundreds of years of traditional use.
Kava is a staple in many traditional communities
It does appear that kava related liver damage is rare in traditional communities. A survey conducted in Samoa in 2002 failed to find one case, even in heavy kava drinkers.6 A survey from one Arnhem Land community in Australia showed only some mild and reversible changes in liver enzymes (probably due to enzyme induction rather than liver damage), with no evidence of liver damage.7 According to Singh and Singh, in the South Pacific mainly men drink kava, often habitually and in much larger amounts than used in the West, yet their incidence of liver toxicity is low and similar to that of island women who do not take kava.8
An Australian doctor recalls that he spent two years living in Vanuatu, observing the regular and occasionally heavy kava consumption. Clinical evaluation revealed occasional cases of kava-related skin rashes and presumptive kava-related cerebral damage. At no time during his two-year stay did he encounter any case of unexplained hepatitis, despite his vigilance since 20% of the population were hepatitis B carriers.9 A doctor working in Auckland with the Pacific Island community reported a similar lack of hepatotoxicity in frequent traditional kava users.10 A small survey of 150 staff and patients at a Vanuatu hospital found that a high frequency of men and women drank kava on a regular basis without any adverse effects.11
The evidence doesn’t support liver toxicity with typical use
A clinical survey and critical analysis by Teschke’s group of 26 suspected cases of kava hepatotoxicity excluded kava as the cause in 18 cases.12 Only one out of the remaining eight patients adhered to the conditions recommended by European regulatory authorities (no more than 120mg/day of kava lactones and three months of continuous therapy). The group concluded that kava taken as recommended is associated only rarely with hepatotoxicity, whereas excessive doses, prolonged treatment and comedication with drugs may carry an increased risk.
The validity of the causality evaluation methods applied in kava hepatotoxicity cases has also been questioned by the same research group. Scales of causality such as the WHO and Naranjo scales, as used by the German authorities, were suggested to be inappropriate due to their lack of liver specificity.13 When the liver-specific Council for International Organisations of Medical Sciences (CIOMS) scale was applied to reported cases for kava, a greatly reduced likelihood of causality was found, compared to the other scales.13,14
Careful and cautious is best with kava
However, it is always best to be cautious. In August 2002, the Australian TGA advised that kava containing medicines should carry a label warning that kava has been implicated in serious liver damage and should be taken only under the supervision of a healthcare practitioner for short periods, not exceeding six weeks. In August 2003, an expert committee of the TGA determined that only certain forms of kava were suitable for use. Permitted products must be made from a water extract/dispersion or from the whole rhizome and the daily dosage of kava lactones must be limited to 250mg. People taking kava should be closely monitored for signs and symptoms of liver damage. These include consistent nausea, jaundice or weight loss. If you are a consistent user of kava, make sure you have a regular liver function test (really a ‘liver damage’ test) and discontinue the kava if there are any adverse findings.
Used wisely, kava is a safe and effective aid for good sleep and to relieve moderate anxiety.To your better health,
Nutrition & Healing
Volume 7, Issue 11 – November 2013
Full references and citations for this article are available in the downloadable PDF version of the monthly Nutrition and Healing issue in which this article appears.