Kavakava - Scientific Background
The effects of kavakava may differ among individuals.
Whereas some studies have found that kavakava pyrones induce a stimulant activity, some studies report a sedative activity, and still others report no activity (Frey, 1991).
Exactly how kavakava works is unknown, but kavakava pyrones show some evidence of an effect on specific molecules on the surface of brain cells (benzodiazepine-binding sites) (Davies et al, 1992). Certain anxiety-reducing drugs act on these molecules.
The typical effect of kavakava in mammals is to induce a state of mild tranquility without reducing alertness (Herberg 1993).
Kavakava can reduce anxiety.
Randomized clinical trials of a standardized extract containing moderately high doses of kavakava pyrones have shown an antianxiety effect superior to placebo (Kinzler et al 1991).
In the largest and first long-term study (101 psychiatric outpatients), anxiety symptoms were reduced by 67% among those taking kavakava for 25 weeks, whereas patients taking placebo had a 52% symptom reduction (Volz and Kieser 1997). Kavakava was also more effective than placebos for anxiety treatment in seven clinical studies reviewed by Pittler and Ernst (2000).
In a study of women with hot flashes, sleep disturbances, or emotional problems related to menopause, the women receiving kavakava were found to have reduced symptoms in all three categories as compared to those receiving a placebo (Warnecke 1991).
Kavakava was found to be as effective as a standard antianxiety drug. A study of 38 psychiatric outpatients found no differences in anxiety reduction between those randomized to receive kavakava or the antianxiety drug oxazepam (Lindenberg and Pitule-Schodel 1990).
Kavakava may reduce pain.
Although the effect may not be strong and may be quite variable from person to person, kavakava possibly works as a mild painkiller. This belief is supported by an animal study (Jamieson and Duffield 1990) showing extracts of kavakava to reduce pain sensitivity. Four different substances in kavakava were found to individually have pain-killing properties. Kavakava may work through a mechanism different from that of opiates and may be of interest to persons who do not tolerate codeine.
Kavakava may support sleep.
There are many claims and at least one animal study that suggest kavakava supports sleep (Holm et al 1991). Apparently, kavakava action is different from the sedation caused by barbiturates and benzodiazepines, which are typical substances in sleeping pills. Kavakava seems to dampen the emotional interference that may hinder sleep.
Kavakava may help muscles relax.
Informal reports of the ability of kavakava to relax muscles are backed up by studies in various animal species. Extracts of kavakava (Singh 1983) and certain individual substances in kavakava (Seitz et al 1997), can be shown to relax skeletal muscle. As yet, there is no agreement on just how kavakava may help muscles relax.
Kavakava appears to be safe.
Although more research is needed, negative side effects of kavakava appear to be rare (Stevinson et al. 2002). However, kavakava has been associated with serious liver problems including hepatitis, cirrhosis, and liver failure, in addition to milder skin and neurologic complaints (Stevinson et al. 2002). Talk to your doctor before taking kavakava if you have a history of liver problems.
At dosage levels used in clinical trials, there are no reports of the rough scaly rash seen among very heavy kavakava users in Polynesia or the metabolic abnormalities that follow prolonged use of kavakava at abusive levels (Mathews et al 1988).
