Kava, an Ethnomedical Review
v 1.1 2006
Citation: Kilham C. "Kava, an Ethnomedical Review". U-Mass Teaching Notes 2000 - 2005. 2006. Erowid.org/plants/kava/kava_article1.shtml
Kava and its CultureThe island communities of the South Pacific, from Hawaii and the Marianas islands along the Tropic of Cancer down to New Zealand below the Tropic of Capricorn, form an area known as Oceania, which includes the three distinct cultural regions of Polynesia, Melanesia and Micronesia. The Marshall and Solomon islands, New Guinea, Fiji, Samoa, Tonga and Tahiti are all found within Oceania, whose diverse island people are a pan-cultural, multi-ethnic melange. Oceania offers some of the most exotic island life on Earth. The swaying palm trees, volcanic landscapes, glistening sandy beaches, vast coral reefs, and indigenous native cultures of Oceania represent a notion of paradise widely held among peoples of other parts of the world.
Virtually every culture has its indigenous and favored mind-altering substances. From one culture to the next, stimulants, narcotics, soporifics and vision-producing plants, beverages and other preparations play important social roles and are part and parcel of religious ceremony, community sharing, special occasions and significant events. In Southeast Asia, betel nut is the widely used stimulant of choice, whereas in Andean society the chewing of coca leaf is central to society. The Mexican Huichol have their peyote, the African Kung and pygmies smoke cannabis, various South American tribal people rely on visionary plant mixtures such as ayahuasca, and so-called "developed" nations are awash in alcohol and their atmospheres are filled with the effusion of tobacco smoke. Coffee, chocolate, tea, guarana, kola nut and yerba mate' are widely-consumed caffeine-bearing drugs which stimulate the nervous system.
In Oceania kava is an esteemed mind and mood altering agent which occupies an central place in culture and custom. Kava is the name of both the plant Piper metysticum, and a pungent beverage prepared from its roots. A robust and attractive perrenial shrub with smooth, heart-shaped green leaves, kava is a member of the Piperaceae, or pepper family, whose 2000 or more diverse species have been widely distributed throughout Africa, India, Southeast Asia and Indonesia since antiquity. A small number of Piper species are used as spices and medicines, including Piper nigrum, from whose red berries both black and white peppers are prepared, and Piper betle, whose nut contains a stimulant known as arecoline, is chewed with lime throughout much of Southeast Asia.
Kava, The PlantPiper Methysticum, or cultivated kava, is a descendant of wild kava, Piper wichmannii. Botanists assert that at one time all kava was Piper wichmannii. But cultivated kava is greatly preferred over wild kava, which is only rarely used as an "extender" when cultivated kava is in short supply.
A lush, leafy green plant, kava grows densely and is harvested when it is approximately six to eight feet in height. Kava is planted in a manner similar to that of sugarcane. Sections of kava stalks are laid in trenches of mud, where they sprout. Once sprouted, the stalk sections are planted in shallow trenches, where they grow to maturity in five to seven years. By that point, kava roots have typically become a thick, knotted mass, and are suitable for the preparation of the kava beverage. Once planted, kava roots continue to grow, sending up new stalks. Thus kava gardens and plantations grow perennially, and are typically passed on through successive generations.
As is true with countless plants used for human consumption, including tomatoes, bananas, apples, coffee and rice, there are numerous varieties of kava under cultivation. The various cultivars of kava are distinguished by both their physical characteristics and by their effects upon body and mind. In kava, the kavalactones, the pharmacologically active compounds in the kava plant and beverage, act upon body and mind, while the relative proportions and potencies of the kavalactones from one variety to another determine the nature and intensity of psycho-somatic effects.
Physical characteristics of kava plants may vary widely. Various kava cultivars or varieties are distinguished by the colors of their leaves and stalks, the thickness of stalk joints, stalk length between joints, the presence of spots and other visible factors. Certain plant cultivars are more highly prized over others, and almost every kava grower has favorite cultivars which are preferred for their effects. In 1902 western botanists identified nine varieties of kava in Samoa. In 1935 twenty-one varieties found in the Marquesas were listed in botanical literature. In 1940 fourteen Hawaiian varieties were known, and in 1984 over seventy-two varieties were reportedly cultivated on the islands of Vanuatu.
Varieties of kava are noted for their effects upon body and mind, and are prized for their ornamental and spiritual worth. Kava is central to the rituals and various life passages of the people of Oceania. Thus kava plants are exchanged and used at virtually all significant occasions and ceremonies. Kava plants are sometimes cultivated to grow in specific shapes, and kava plants presented as gifts at weddings and other special occasions are typically decorated. On the island of Tanna in Vanuatu, kava grown for customary exchanges is cultivated in the trunks of tree ferns, yielding attractively shaped kava plants known as nikava tapuga. Historically the consumption of kava made from nikava tapuga was a privilege reserved for chiefs and men of high rank. It is believed that the powerful plant spirit Mwatiktiki dwells in nikava tapuga, which surely accounts for the privilege associated with drinking kava thus cultivated. Chiefs and other people of high rank would, according to custom, be favored with closer relation to such a spirit than individuals of lower social standing. Though this kind of strict social delineation has diminished somewhat over time, social standing still plays an important role in the consumption of kava. Whoever ranks highest at a kava ceremony is served first. Others are served in the order of their social standing within that particular group.
In addition to high ranking native people, other individuals may also be served first or early in kava ceremonies. According to custom, high ranking individuals of other societies and backgrounds typically enjoy preferential staus in kava ceremony. With the exception of Presbyterian church officials, who have vigorously opposed indigenous native kava use as an act against their own one true god, virtually everyone of social significance is served kava when they visit most of the islands in Oceania. President and Mrs. Lyndon Johnson were served kava when they visited Samoa in 1965. Great Britain's Queen Elizabeth and other members of the royal family have drunk kava when they have visited Fiji, as did the Vatican's Pope John Paul II on his Fijian visit in 1986. Ambassadors, dignitaries and officials from other nations are regularly served kava when they visit or hold important meetings on South Pacific islands. Kava consumption is thoroughly integral to life in that region, and is the first act at important community functions and gatherings.
Kava Origin and CultivationThe exact origin of kava remains uncertain, but many botanists believe that kava originated from northern Vanuatu. Others suggest that kava was native to either New Guinea or the Solomon Islands, and that after its effects became known to natives there, it was widely dispersed throughout Oceania by seafaring islanders. One thing is certain, that kava was consumed prior to written history, and its use was very well established throughout the South Pacific when Captain Cook made his first voyage to that area aboard the Endeavour between 1768 - 1771.
Though kava is not cultivated on all South Pacific islands, it is found on many. Kava is grown on Papua New Guinea, Irian Jaya, Fiji, Wallis and Futuna, Western and American Samoa, the Society and Marquesas Islands, Tahiti, Micronesia and Hawaii, where cultivated kava is making a resurgence after being relegated to a cultural relic for decades. Kava's widespread distribution gives testimony to the cultural value and social significance of this plant and its root-derived beverage. Kava and the islands upon which it grows and is consumed have withstood "discovery" by westerners, as well as invasion, colonization, encroachment of developed civilization, the pulpit-pounding of zealous missionaries, political change, reform and upheaval. Through it all, kava has remained for the most part a fixture of life in Oceania. If kava's effects were less profound and valuable, this plant and its use would have been supplanted by alcohol, a cheap sedative/hypnotic. But kava maintains a strong hold in Oceania society, owing to its effects upon, and benefits to, body and mind.
Kava cultivation keeps growers and their friends and communities well supplied with kava, and is part of a sprawling, increasingly lucrative agricultural enterprise ranging over thousands of miles of South Pacific territory. In the archipelago of Vanuatu, the islands of Pentecost, Santo, Tanna, Epi, Ambae, Tongoa and Maewo are the primary kava growing areas. In Vanuatu, kava production is less than that of copra (coconut) and cocoa, but the cash value to small subsistence Vanuatu kava farmers is significant. Kava cultivation requires relatively little labor or capital expenditure, and no chemical agricultural inputs.
Most cultivated kava is used by indigenous people, but an increasing amount of kava isexported for use abroad. French pharmaceutical companies have purchased kava from Vanuatu on a consistent basis for many years. German botanical medicine companies have stepped up their importation of kava, due to a sharp increase in European interest in kava's beneficial effects. U.S. botanical companies purchase kava from Vanuatu and Fiji in increasingly large quantities due to increased popularity and consumer demand for kava products, and market prices of raw kava for export have risen significantly due to increased international demand.
Accounts of kava date back to Captain Cook's second voyage to the South Pacific from 1772 - 1775. Historical, social and scientific literature on kava, garnered from diverse sources including Harvard's Countway Medical Library, the Harvard Botanical Libraries, Hawaii's Bishop Museum, the University of the South Pacific, numerous texts on pharmacognosy, medical, botanical and anthropological journals, and the Internet, reveal a vast, multi-century, multi-disciplinary interest in kava. The plant and its beverage are extraordinarily well studied. Scientific research and economic development opportunities for kava continue unabated, while kava products are increasing in popularity.
Kava as MedicineThough kava's primary use throughout Oceania is as a social, mood-enhancing beverage, the plant is also part of the native pharmacopoeia of that region, and is used medicinally for a wide range of conditions. The primary folk medicinal use of kava is for urogenital inflammation and cystitis. But kava is also drunk to relieve headaches, to restore vigor in the face of general weakness, to promote urination, to soothe an unruly stomach, to cure whooping cough in children, and to ease the symptoms of asthma and tuberculosis. Topically, kava is useful to treat fungal infections and for soothing stings and skin inflammation.
The first researcher to engage in serious investigations into the medicinal applications of kava was Cuzent, who in 1860 made extracts of kava rootstock and roots, and isolated a crystalline substance he dubbed kavahine. Cuzent developed kava-based pills, an oleoresin, an alcohol extract and a syrup. By the end of the 1800's, kava preparations were available in German herbal shops.
In the early 1900's Kava-based remedies made their way into the British pharmaceutical codex, the English Pharmacopoeia. In 1914 kava was listed in the British Pharmacopoeia under the name "kava rhizoma." In 1920 kava appeared in European dispensaries as a sedative and hypotensive. Kava also appeared in the U.S. Dispensatory as a treatment for chronic irritations of the urogenital tract. In 1950 the U.S. Dispensatory listed kava for the treatment of both gonorrhea and nervous disorders, under the names "Gonosan" and "Neurocardin" respectively. Prior to World War II kava from Pohnpei was used by the Japanese for the preparation of a medicine used to treat gonorrhea.
Kava ChemistryKava's chemistry is well documented. The medicinally active constituents of kava are a group of resinous compounds known as kavalactones, or kavapyrones. The kavalactones have been the objects of chemical research since the mid 1800's, and much is known about their mode of activity. While as many as fifteen kavalactones are known, only six appear appear in kava to any significant extent. These six kavalactones are demethoxy-yangonin, dihydrokavain, yangonin, kavain, dihydromethysticin and methysticin.
While today the analysis of the kavalactones is made easy by advanced analytical laboratory machinery, in the 1800's such research was slow, arduous and painstaking. Almost simultaneously, Gobley in 1860 and Cuzent in 1861 isolated the first of the kavalactones, known today as methysticin. Prior to agreement on its proper name, methysticin was known variously as kavatin, kanakin, kavakin and kawakin. The giant scientific step of isolating methysticin opened the door to subsequent chemical progress with the resinous extract of kava. In 1874, Scientists Nolting and Kopp isolated another kavalactone which went nameless until it was dubbed yangonin by Lewin in 1886.
Following the publication of Lewin's seminal 1886 treatise on kava Uber Piper Methysticum , numerous researchers leapt test tube first into the kava fray. In 1908, Winzheimer isolated dihydromethysticin, the most active tranquilizer of all the kavalactones. Between 1914 and 1933, Borsche and his various colleagues isolated two additional kavalactones, kawain and dihydrokawain. They also determined the chemical structures of those two kavalactones and the three others that had been previously discovered. Borsche and his colleagues published a series of 14 papers on the subject, adding greatly to the body of kava science. A chemical error made by Borsche regarding the actual structure of yangonin was corrected in 1950 by Macierewicz, and yangonin was subsequently synthesized in 1960 by Bu'Lock and Smith. In 1959 Klohs, Keller and Williams isolated desmethoxy-yangonin, and in 1962, Mors, Magalhaes and Gottlieb reported the isolation of 5,6-dehydromethysticin, 11-methoxyyangonin and 11-methoxynoryangonin. Further detailed analysis of the structure of kavalactones and their activity has been conducted by Keller and Klohs, Shulgin, and Duve and Duffield.
Parallel to the chemical investigation of the kavalactones, the study of their pharmacology, or drug activity, has also been of keen interest to researchers, and continues unabated to this day. Pioneering plant researcher Lewin was the first to evaluate the activity of the kavalactones. Using kava resin administered by intraperitoneal injection, Lewin found that the compound produced paralysis in frogs, and sedated pigeons and sparrows to such an extent that they were temporarily rendered unable to fly. When resin was injected subcutaneously into cats, the animals fell into a deep sleep. While these experiments may seem crude by today's standards, at the time they were ground-breaking, and set the pace for further pharmacological investigation.
In Schubel's investigations as reported in 1924, he found that kava resin administered in large enough doses produced temporary paralysis of sensory nerves and smooth muscle. Interestingly, Schubel also made a discovery that supported the mastication of kava as the most effective means of preparation. In experiments conducted with frog hearts, he discovered that kava extract was more potent if made from root that had been incubated with saliva. He speculated that the starch digesting enzyme (ptyalin) in saliva more effectively liberated the resinous compounds from the root, thus yielding a stronger extract.
In Van Veen's 1938 work with pigeons, administration of kava resin put the birds to sleep within fifteen minutes. Upon awakening the birds appeared fully revived and recovered. The same results were achieved with monkeys. In an important discovery, Van Veen found that the effect of kava extract was enhanced when put into a lecithin/water emulsion. This has been subsequently confirmed. The presence of lipids such as lecithin or vegetable oils appears to enhance kavalactone absorption and uptake, rendering them more potent.
After Van Veen, the soporific effects of large doses of kava's active agents was subsequently demonstrated by Hansel and Beiersdorff in their 1959 work on the kavalactones dihydrokawain and dihydromethysticin. In 1967, Meyer was able to show that the primary activity of the kavalactones was as muscle relaxants. This work opened the door for further research on the kavalactones as potent skeletal muscle relaxants that work on the central spinal nerves and compare favorably with synthetic drugs used for the same purpose.
While work using the various isolated, synthesized kavalactones has yielded interesting results, the potency of each as a separate molecule is less significant than the potency of all the kavalactones taken together in their natural form. For example, in humans isolated dihydromethysticin must be taken in doses of 800 - 1200 milligrams to produce a tranquilizing effect. Yet a single coconut shell of kava, yielding approximately 250 milligrams of total kavalactones, can produce a tranquilizing effect. In 1959 Klohs was able to demonstrate that there is a synergistic activity among the kavalactones that enhances their potency when taken together. This is not an uncommon finding in the investigation of natural substances. Time and again researchers discover that the extraction and isolation of specific molecules produces an inferior medicine as compared with the same compound in its natural complex of ancillary and related compounds.
While kava produces no side effects when taken in moderate doses, its abuse can lead to health problems. A 1988 study of heavy kava users in Arnhem Land in Australia showed that excessive kava consumption in the range of 310 to 440 grams of kava per week contributed to deteriorating health. Such amounts require the consumption of gallons of kava per day, a significant feat. Heavy abusers studied suffered from shortness of breath, dry, scaly skin, liver damage, malnutrition and alterations in red and white blood cells and platelets. The malnutrition was due to the fact that kava consumption replaced much of the subjects' food intake. Alcohol and tobacco intake was also high among the people studied.
Kava the Tranquil DrugKava holds great promise for the mitigation of three of the most common health disorders, anxiety, depression and sleeplessness. The effects of stress and anxiety can include weakened immunity, nervousness, indigestion, difficulty concentrating, sleeplessness and an overall haggard feeling. When anxiety blossoms into full-blown panic, symptoms can include tachycardia, palpitations, dizziness, syncope, trembling, dyspnea, chocking or smothering sensations, paresthesias, and extreme fears of dying, losing control of the mind, or performing horrible acts.
To combat these symptoms of anxiety, many people turn to alcohol and other drugs, including prescription tranquilizers and sleep aids. As a cheap, readily-available sedative/hypnotic of high potency, alcohol remains far and away the most widely used and abused anti-anxiety drug. While alcohol can mitigate anxiety when consumed in moderate doses, it is habit-forming because the longer it is used the higher the concentration is needed to produce the desired tranquilizing effect. In less than moderate doses, alcohol produces intoxication characterized by reduced motor control, impaired judgement, and often, aggressive behavior. Excessive use leads to addiction, liver disorders, impaired brain function, and degenerative organ and nerve damage. In addition, alcoholic intoxication is implicated in the deaths of tens of thousands of motorists every year, is a key factor in a high percentage of cases of domestic violence, and is universally known for its provocative role in other instances of criminal and social violence. On the other hand, use of tranquilizers, especially the benzodiazepine class of drugs which includes Valium®, Halcion®, Serax®, and Xanax®, can lead to addiction and extreme complications including seizure disorders, vision problems, headaches, anorexia, neuromuscular difficulties and psychosis. While the use of these and other so-called wonder drugs such as Prozac® is virtually ubiquitous at this point in time, the safety of these drugs is marginal, and the numbers of people who have experienced unwanted side effects as a result of using them are legion.
According to the National Foundation for Brain Research, 16.6 to 22.8 percent of US women, and 10.9 to 16.7 percent of US men, suffer from anxiety disorders. Using the mean figure for approximate calculations, about 50 million US adults battle with anxiety. According to the National Institutes of Health Office of Medical Applications of Research, panic disorder may affect as many as 3 million Americans in the course of a lifetime.
There are well established connections between anxiety and depression. While not all depression is associated with anxiety, shared neural pathways and mechanisms in the human brain account for such a connection in many cases. Furthermore, anxiety is a common symptom of depression, thus blurring the lines between the two conditions. For this reason, drugs such as the benzodiazepines Deracyn® and Zofran®, as well as more than a dozen other drugs in development, are prescribed for both conditions. According to the National Institutes of Mental Health, during any six month period, 9 million Americans suffer from a depressive illness, costing the nation over $30 billion per year, at least half of which is due to absenteeism. Currently the drug of choice for depression is Prozac®, the first-ever $2 billion dollar anti-depressant.
As part of the syndrome of either depression or anxiety, sleeplessness is yet another problem which results in the fraying of the mind and exhaustion of the body. It is estimated that 60% of American adults experience some degree of occasional insomnia. Either they have trouble falling asleep, they wake up in the middle of the night and can't get back to sleep, they sleep fitfully and toss and turn, or they lie in an uncomfortable half-sleep, and rise in the morning feeling exhausted. Whatever the nature of a person's insomnia, the condition is a robber of badly needed rest. Not all insomnia is due to anxiety or depression, but the connection exists in many cases.
While many people experience benefits from anti-anxiety drugs, getting off of these drugs can be uncomfortable, and highly risky in some cases. The documented symptoms of benzodiazepine withdrawal syndrome include anxiety, agitation, tremulousness, insomnia, dizziness, headaches, anorexia, tinnitus, blurred vision, diarrhea, hypotension, hyperthermia, neuromuscular irritability, psychosis and seizures.
The task of brain researchers has been, and continues to be, to plumb the depths and breadth of this magnificent organ, and to determine, among other things, what happens where. One area of the brain known as the limbic system, which is highly developed in mammals and therefore dubbed the "mammalian brain," is a collection of structures including the fornix, hippocampus, hypothalamus, pituitary gland and amygdala. The limbic system is key to feelings of fear, anger, sadness and the myriad of complex psychophysical responses we call emotions. In addition, homeostatic mechanisms in the limbic system regulate blood pressure, heart rate, body temperature, blood sugar, sexual impulses, eating, drinking, sleeping, and waking. While various parts of the limbic system play unique roles (the pituitary for example plays a key role in hormonal regulation), the components of the limbic system seem to work in concert through a labrynthine network of interconnecting fibers and pathways. Given these interconnections, it is easy to appreciate how fear and sleeplessness, or loss of appetite and heart palpitations, could go together. They, and many other functions, are all regulated by the limbic system.
The activity of psychiatric drugs occurs in the brain. The benzodiazepines for example, augment the activity of gamma-aminobutyric acid (GABA) in the limbic system. It is known that decreased GABA activity promotes anxiety. These drugs bind to receptor sites (areas where certain chemicals fit onto specialized cells) in the brain, enhancing the activity of GABA and producing a feeling of tranquility. By an entirely different route, Prozac enhances the action of serotonin, a neurotransmitter or chemical messenger, which operates in the transmission of information from one neuron (nerve cell) to another.
In the limbic system, a small organ the size of a chick pea, the amygdala (of which there are two, one left, one right), regulates feelings of fear and anxiety, and processes memories en route to the cerebral cortex. This little organ, whose name means "almond" due to its shape, is a significant site of activity for both the benzodiazepine class of drugs, and for the natural, tranquil plant drug kava. A 1989 National Advisory Mental Health Council report noted that "Benzodiazepine receptors are located in many different regions of the limbic system, as well as other parts of the brain. However, researchers found recently that benzodiazepine receptors are highly concentrated in a particular region of the brain called the amygdala that is critical to emotional processing, suggesting that this structure may be an important site of their action." In studies reported by Holm in 1991, the preferential site of action for both whole kava resin and synthesized kawain was the amygdala. However, unlike the benzodiazepines, the kavalactones did not appear to interact with GABA or its receptor sites, but operated by other, as yet unknown means.
Kava And Human StudiesKava has been successfully used in the treatment of anxiety, as demonstrated in the following studies.
In a double-blind, placebo-controlled study of eighty-four patients suffering from anxiety, a daily dose of 400 mg of purified kavain improved vigilance, memory and reaction time.
Though kava's promotion of a good night's sleep is thoroughly well documented throughout history and is corroborated by the anecdotal accounts of numerous avid daily kava drinkers, a study showed that administration of kavalactones to humans does indeed induce sedation and sleepiness.
In a study of thirty-eight patients suffering from anxiety, kavain and oxazepam, a benzodiazepine marketed under the trade name Serax, were compared over a period of four weeks. Both reduced symptoms of anxiety equally as measured by both the Self-Rating Anxiety Scale and the Anxiety Status Inventory. However, unlike kavain, oxazepam is addictive and produces side effects such as drowsiness, dizziness, headaches and vertigo. This study made it clear that the kavalactones possess anti-anxiety activity comparable to the benzodiazepines, but without the hazards.
In a four week study of fifty-eight patients suffering from anxiety, twenty-nine were given 100 milligrams of a 70% kavalactone extract three times daily, whereas the control group was given a placebo. Those who took the kava extract experienced significant reduction in anxiety after just one week, and were markedly improved at the end of the study. As with other studies, no adverse effects were reported as a result of the kava use.
In an eight week study of forty women with menopausal symptoms, twenty women were given a daily dose of 100 milligrams of kava extract standardized to a 70% kavalactone value, and twenty were given a placebo. The group given the kava experienced a significant reduction in menopausal symptoms, anxiety, and depression, whereas the control group experienced no significant change.
In a study of twelve volunteers, the effects of a standardized kava extract and oxazepam on mental function were compared. Using several parameters, oxazepam was shown to decrease both the quality and speed of responses to test questions, whereas the kava extract did not adversely affect mental function. In a word recognition test, oxazepam slowed reaction time and reduced the number of correct answers, whereas the kava extract slightly increased reaction time and recognition. This supports the oft-repeated claim of kava users that even when enough kava is consumed to cause sedation, there is no impairment of mental function, including memory or clarity of thought.
In a battery of tests given to forty subjects, kava extract administered to volunteers did not impair their performance driving an automobile or operating heavy machinery. Unlike alcohol or the benzodiazepines, kava taken in appropriate doses does not impair coordination, visual perception or judgement.
Unlike the benzodiazepines, kava's effectiveness does not diminish over time, whereas a person taking Valium, Xanax or Oxazepam may need to increase their daily dose over time to achieve the same anti-anxiety effect.
2001 Studies Boost Kava Safety, EffectivenessTwo studies conducted at Duke University Medical Center show that kava extract is safe, and works as effectively as prescription drugs for treating anxiety and stress. These latest studies add to a growing body of positive science on kava. For treating stress and anxiety, kava is validated by several human clinical trials. Kava's activity is due to the presence of kavalactones, resinous compounds found in the plant.
Both Duke studies used a standardized kava extract (KavaPure, PureWorld Botanicals). In one study, researchers Kathryn Connor, John Davidson and Erik Churchill found that "Kava has several advantages over conventional pharmacologic treatments for anxiety - in clinical settings kava has been associated with better tolerability and lack of physiologic dependence and withdrawal." These reduced risks make kava a good choice for those who need relief from anxiety and stress, but wish to avoid the well-documented hazards associated with prescription drugs.
In safety tests, the researchers found no problems with kava extract. Examining withdrawal symptoms, heart rate, blood pressure and sexual function, kava extract tested as safe as a placebo. The Duke doctors noted that "Kava is generally well tolerated, with very few side effects at recommended doses."
In the second study, Duke researchers Lana Watkins, Kathryn Connor and Jonathan Davidson found that kava extract improves baroreflex control of heart rate (BRC) in patients with anxiety disorder. According to the researchers, "Anxiety disorders are associated with low vagal control of heart rate and increased risk of cardiac mortality and sudden cardiac death." They further noted that "Moreover, improving vagal control prevents the occurrence of lethal dysrhythmias in clinical studies." If you can increase BRC, you can reduce the risk of heart attack. And kava appears to do exactly that.
Kava extract proved to be an effective anti-anxiety agent, and also significantly increased BRC. This finding suggests that kava extract may reduce a lethal cardiac risk factor. Further studies are needed to repeat this effect.
The overall conclusion reached by the Duke researchers was that kava can be used to effectively treat anxiety at 280 milligrams of kavalactones per day.
Dosage GuidelinesIt is clear that kava offers a safe, effective alternative to prescription drugs for anxiety and insomnia, and that kava can in some cases provide relief for depression. The most significant anti-anxiety studies show that an effective daily dose of kavalactones ranges between 210 - 280 milligrams of kavalactones. To promote sleep, a dose of approximately 140 - 210 milligrams of kavalactones taken thirty to sixty minutes prior to retiring is recommended.
AddendumIn November 2001, the German Federal Institute of Drugs and Medical Devices issued a letter to all manufacturers of phytomedicine products made of kava (Piper methysticum) manufactured and marketed in Germany. The letter informed these companies of governmental intentions to withdraw the authority to market these products and requested that the companies to respond within four weeks.
The reason cited for this action was that in the past several years, there have been 24 adverse event reports (AERs) of hepatotoxicity reportedly associated with oral use of kava preparations in Germany and Switzerland. In response to the German action, the American Herbal Products Asssociation (AHPA) contracted Donald P. Waller Ph.D., Professor of Pharmacology and Toxicology at University Of Illinois at Chicago, to undertake a thorough toxicity review of the 24 cases. His "Report On Kava and Liver Damage" assessed each case. The following is Doctor Waller's conclusion:
Conclusions"It is my opinion, based on currently available information, that kava when taken in appropriate doses for reasonable periods of time has no scientifically established potential for causing liver damage. However as with any pharmacologically active agent, there is always the possibility of drug interactions, preexisting disease conditions and idiosyncratic or hypersensitivity reactions, which can exacerbate the toxicity of any such agent. Increased surveillance or reports of adverse effects and judicious use of kava-derived products under the conditions recommended by the natural products industry would be a most prudent approach to confirm its safety and minimize any risk of liver damage."