A calming herb from the South Pacific
By many accounts, kava-kava—or simply kava—is an herb on the brink of Western stardom. Manufacturers of herbal products report strong public interest in kava preparations, and articles appearing in the popular press have described kava use and its effects, both good and bad. While many Americans are becoming increasingly aware of kava’s ability to relax tension, increase sociability, and promote sleep, their discovery of kava’s tranquilizing, calming effects comes relatively late, given that kava has been part of the cultural tradition of the South Pacific for thousands of years.
From Hawaii to New Guinea, natives of the South Pacific islands serve a special drink made from kava rootstock at weddings, coming-out-of-mourning celebrations, and other special occasions; visiting heads of state have indulged in kava during welcoming ceremonies. Considered an important part of the islanders’ social and religious lives, kava’s cultural role in the Pacific has been compared with that of wine in southern Europe.
In former times, the islanders prepared the ceremonial kava beverage by first scraping the root, then chewing pieces of it and spitting them into a bowl to which coconut milk or water was added. Next, they stirred the mixture until it took on a muddy, opaque appearance, then strained it into another bowl. During ceremonies, a cup of the beverage was first presented to a special guest, who was expected to down the contents without stopping. Then others attending the ceremony imbibed.
Today, the root is usually prepared by grating, not chewing. Initially, many islanders opposed giving up the chewing method because they believed that it produced a stronger drink. Some researchers, in fact, concur with this belief. Chewing apparently releases more kavalactones—compounds found in kava that relax muscles—than grating, because saliva contains an enzyme that breaks down the starchy components of kava pulp.
Islanders (as well as many new kava drinkers) take moderate amounts of the beverage to achieve a state of tranquility, happiness, and contentment (some describe it as a holistic sense of “being”), but without the unpleasant side effects of alcohol, such as hangovers or boisterous behavior. Overindulging can lead to loss of muscle control and a strong urge to sleep.
The islanders have also used kava as medicine for centuries, brewing decoctions made from its rootstock to treat gonorrhea, urinary infections, menstrual problems, migraine headaches, insomnia, and other conditions.
Captain James Cook is credited with introducing kava to the West after a voyage through the South Pacific from 1768 through 1771. Later, it was given its botanical name, Piper methysticum, reflecting both its close relationship to the familiar spice black pepper (P. nigrum) and its intoxicating effects (methys is Greek for “drunken”). Kava is a shrub that thrives in humid, tropical climates with evenly distributed rainfall and stony soil at elevations of 500 to 1,000 feet above sea level. Plants can reach heights of 20 feet, and their sprawling rhizomes may reach lengths of 9 feet, alternately disappearing below and surfacing above the soil. The islanders harvest kava when the shrubs mature in two to three years, either to use themselves or sell as a cash crop.
Kava first piqued scientific interest during the mid-1800s, when researchers traced kava’s relaxing properties to kavalactones, which relax muscles without blocking nerve signals that keep the muscles tense. This may explain how kava can relax muscles without numbing the thinking process. But kava’s mind-altering action has largely been ignored in modern times due to the development of synthetic psychopharmaceuticals, including antidepressants. Recently, however, kava and other plant therapies have received more attention because undesirable side effects, including addiction, can make some synthetic drugs unsuitable for long-term treatment.
Kavalactones have been shown to relieve anxiety and pain and relax muscles in laboratory animals. In humans, they have been shown to change brain activity (as measured by an electroencephalogram) without sedation. A recent study showed that people taking measured doses of a kava extract fared better in word-recognition tests than those taking a synthetic tranquilizer (benzodiazepine), and a 1993 report in the British Journal of Phytotherapy referred to kava as one of few herbs that can safely relax skeletal muscle. The report’s author recommended it for treating nervous tension and conditions associated with skeletal muscle spasms, such as headaches caused by a tense neck.
In 1996, a randomized, placebo-controlled, double-blind study showed that kava significantly reduced anxiety in humans. Two groups of twenty-nine people with normal anxiety were treated for four weeks with three daily doses of 100 mg of kava rhizome extract or a placebo. After one week of treatment, members of the kava group had significantly lower anxiety levels compared with that of the placebo group, and the difference between the two groups increased during the course of the study. No adverse reactions to the kava extract were noted during the study.
A 1995 report, however, described four patients who experienced unpleasant side effects from using various kava preparations. A twenty-eight-year-old man, who had been taking pharmaceuticals for treatment of anxiety, had sharp spasms in the muscles of his neck and eyes that began about ninety minutes after taking 100 mg of kava extract and lasted about forty minutes. A twenty-two-year-old woman experienced a similar reaction to the same product but denied taking any other medication, as did a sixty-three-year-old woman who had taken 150 mg of kava extract three times daily for four days to treat anxiety. Finally, a seventy-six-year-old woman with early signs of Parkinson’s disease (a disorder of the nervous system) reported a pronounced increase in the duration and number of episodes of impaired movement after switching from pharmaceuticals to 150 mg of kava extract, which she took twice a day. The study’s authors suggested that kava products be used cautiously, especially by elderly patients.
When used as directed, standardized kava products are considered nonaddictive, nonhypnotic, and safe to use, except during pregnancy, lactation, or bouts of depression. The German government’s Commission E warns against using kava with alcohol, barbiturates, antidepressants, and other substances that may act on the central nervous system. Because it apparently acts like a sedative, kava shouldn’t be taken when driving or operating machinery. No side effects have been associated with using small amounts of kava products, but long-term, heavy use can cause temporary yellowing of the skin, hair, and nails, as well as itching, sores, and vision disturbances. In Germany, where the dried rhizome and its preparations are sold commercially, the government allows kava preparations to be labeled as treatments for nervous anxiety, stress, and unrest.
Overindulgence in kava, like any other drug, poses dangerous health risks. It is best to follow the guidelines offered on the label of the product you are using or the instructions of your health-care provider.
• Brown, Donald J. Herbal Prescriptions for Better Health. Rocklin, California: Prima, 1996.
• Foster, Steven. Herbs for Your Health. Loveland, Colorado: Interweave Press, 1996.
• Lehmann, E., et al. “Efficacy of a Special Kava Extract (Piper Methysticum) in Patients with States of Anxiety, Tension and Excitedness of Non-Mental Origin—A Double-Blind Placebo-• • • Controlled Study of Four Weeks Treatment”. Phytomedicine 1996, 3(2):113–119.
• Leung, Albert Y., and S. Foster. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics. 2nd ed. New York: Wiley, 1996.
• Schelosky, L., et al. “Kava and Dopamine Antagonism”. Journal of Neurology, Neurosurgery and Psychiatry 1995, 58(5):639–640.
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