Kava: Difference between revisions
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Revision as of 18:57, 7 May 2007
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Kava (Piper methysticum) is an ancient crop of the western Pacific. Other names for kava include ʻawa (Hawaii), 'ava (Samoa), yaqona (Fiji), and sakau (Pohnpei). The word kava is used to refer both to the plant and the beverage produced from it.
Preparation and consumption
Kava is prepared and consumed in a variety of ways throughout the Pacific Ocean cultures of Polynesia, Vanuatu, Melanesia and some parts of Micronesia and Australia. Traditionally kava has been prepared by either chewing, grinding or pounding. Chewing the kava consists of masticating it in the mouth, depositing it back into a bowl, mixing with water and then straining it through the cloth-like fiber of a coconut tree. Another method is grinding in which the kava is ground by hand against a cone-shaped block of dead coral; the hand forming a makeshift mortar and the coral cone, a pestle. The moist ground kava root is combined with only a small amount of water as the fresh root releases a good deal of moisture during grinding. The last method is by pounding the kava in a large stone with a small log. Kava prepared in any of these ways is significantly more potent than unprocessed kava. The product resulting from these methods is then added to cold water and consumed as quickly as possible.
The extract is an emulsion, consisting of suspended kavalactone droplets in a starchy suspension. The taste is slightly pungent, while the distinctive aroma varies depending on whether it's been prepared from dry or fresh material, and by variety. The colour is grey to tan to opaque greenish.
Various sources incorrectly state that preparation technique of mastication potentiates the psychoactive effects of kava because of the action of saliva enzymes on the plant. Although chewing kava does produce a more powerful effect than any other form of preparation, this is not the result of any chemical process; rather, this is due to the much finer particles produced in this method.
The strength of prepared kava also depends on its species, freshness, and techniques of cultivation. Fresh, undried kava produces a stronger beverage than old, dried kava.
Fijians commonly share a drink called Grog that is prepared by pounding sun-dried kava root into a fine powder and mixing it with cold water. Traditionally, Grog is drunken from the shorn half-shell of a coconut, called a "bilo." Despite tasting very much like dirty water, Grog is very popular in Fiji, especially among young men, and often serves to bring people together for storytelling and socializing. [1]
Kava can also be combined with coffee to produce kavajava, the effects of which are said to combine the most pleasant qualities of each.
Effects
The onset of a moderate potency kava drink is 20-30 minutes, with effects usually lasting for two hours. Effects can be felt up to eight hours after ingestion.
These effects of drinking kava, in order of sensation, are slight tongue and lip numbing caused by the contraction of the blood vessels in these areas (the lips and skin surrounding may appear unusually pale); mildly talkative and euphoric behavior; anxiolytic (calming) effects, sense of well-being, clear thinking; and relaxed muscles. Sleep is often restful and there are pronounced periods of sleepiness correlating to the amount and potency of Kava consumed. When drunk to excess, Kava can cause vomiting and a feeling of nausea that will subside usually by the end of the day after consumption. In Vanuatu, drinking strong kava is normally followed by a hot meal or tea. Meals consumed along with kava traditionally follow some time after the beverage so that the psychoactives are absorbed into the bloodstream more quickly.
A drink of high potency results in a faster onset with a lack of stimulation, somnolence, and then deep, dreamless sleep within 30 minutes. Unlike alcohol-induced sleep, after wakening the drinker does not experience any mental or physical after effects.
Heavy consumption of kava can produce dermatological effects ranging from light, red bumps; to heavy, scaly, ulcerous skin. Kava contains lactones that bind to skin proteins forming antigens which then lead to the allergic response. Discontinuation or reduction of consumption resolves the effects.
It is reported that many people experience rather vivid dreams after consumption of kava. [1]
Pharmacology
Pharmacologically, kava is not addictive. Its active principal ingredients are the kavalactones, of which 15 have been identified and are all considered psychoactive. Only six of these kavalactones produce noticeable effects, and their concentrations can vary in kava plants. Different ratios can produce different effects.
Fresh kava root contains on average 80% water. Dried root contains approximately 43% starch, 20% fibers, 15% kavalactones, 12% water, 3.2% sugars, 3.6% proteins, and 3.2% minerals. Kavalactone content is greatest in the roots and decreases as you move up the plant. Relative concentrations of 15%, 10% and 5% have been observed in the root, stump, and basal stems, respectively.
Kava has been considered to be relatively safe. Having been consumed for at least two thousand years, kava's safety record is indeed very high. Yet, some kava herbal supplements have been accused of contributing to rare but severe hepatotoxic reactions likely due to additives or to the use of the wrong parts of the plant (see section on safety).
Kava culture
Kava is used for a variety of purposes, medicinal, religious, political, cultural and social throughout the Pacific. These cultures have a great respect for the plant and place a high importance on it. Kava is used primariarly in social gatherings to increase amiability and to relax after a day's work. It additionally has great religious significance, being used to obtain inspiration. In some Westernized Pacific-peoples, the drink has been demonized and seen as a vice; it is not uncommon for youth of such populations to reject their traditional cultural ties with the plant. However, it has gained a cult following among the youth culture of caucasian people living on Pacific islands.
Kava botany & agronomy
There are several cultivars of kava, with varying concentrations of both primary and secondary psychoactive substances. The Republic of Vanuatu is recognised as the "home" of kava because it hosts the largest number of cultivars. The kava plant has historically been grown only in the Pacific islands of Hawaii, Federated States of Micronesia, Vanuatu, Fiji, the Samoas and Tonga. In modern times (i.e., since WW2) there has been some kava grown in the Solomon Islands, but most kava used in that country is imported. Kava is a cash crop in Vanuatu and Fiji.
The kava plant, a shrub, thrives in well-drained soils and it grows well as an understory crop (i.e., too much sunlight, especially in early growth, is deleterious). It grows naturally where rainfall is plentiful (over 2,000mm/yr). Ideal growing conditions range from 20-35 degrees celsius (70-95 fahrenheit), and 70-100% relative humidity. The soil it is kept in should be loose to ensure plenty of air reaching the root.
Kava is unable to sexually reproduce. Female flowers are especially rare and do not produce fruit even when hand-pollinated. Its propagation is entirely due to human efforts by the method of striking.
Traditionally, plants were not harvested until they were around 4 years of age, as older plants have higher concentrations of kavalactones. However, over the past two decades farmers have been harvesting younger and younger plants--even as young as eighteen months. Older plants are not much taller (around 2m.) than younger plants; growth adds diameter to the culm and more stalks than height. A grown plant's roots can reach up to 60 centimeters in depth.
Medicinal kava
In the Western world, kava is commonly marketed as a herbal remedy to ease the symptoms of stress and anxiety.
On 15 February 2006, the Fiji Times and Fiji Live both reported that researchers at the University of Aberdeen in Scotland, and the Laboratoire de Biologie Moleculaire du Cancer in Luxembourg had discovered kava may be effective in the treatment of ovarian cancer and leukemia. Kava compounds inhibited the activation of a nuclear factor that led to the growth of cancer cells. Aberdeen University had published its findings in the journal, The South Pacific Journal of Natural Science, that kava methanol extracts had been shown to kill leukaemia and ovarian cancer cells in test tubes. The kava compounds were shown to work selectively, passing healthy cells by and targeting only cancerous cells.
Fiji Kava Council Chairman Ratu Josateki Nawalowalo welcomed the findings, saying that they would boost the kava industry. For his part, Agriculture Minister Ilaitia Tuisese called on the researchers to help persuade members of European Union to lift their ban on kava imports.
Safety
In the year 2001 concerns were raised about the safety of commercial kava products.[2] There have been indications[3][4] of severe liver toxicity, including liver failure in some people who had used dietary supplements containing kava extract. The severity of liver damage consequently prompted action of many regulatory agencies in countries where the legal precautionary principle so mandated. In the UK, the Medicines for Human Use (Kava-kava) (Prohibition) Order 2002 prohibits the sale, supply or import of most derivative medicinal products. Kava is banned in Switzerland, France and The Netherlands[citation needed]. The health agency of Canada issued a stop-sale order for kava in 2002. However, subsequent legislation in 2004 rendered the legal status of kava in question.Cite error: The opening <ref> tag is malformed or has a bad name (see the help page). The United States CDC has released a report[5] expressing reservations about the use of kava and its possibly adverse side effects (specifically severe liver toxicity), as has the Food and Drug Administration (FDA).[6] The Australian Therapeutic Goods Administration has recommended that no more than 250mg of kavalactones be taken in a 24 hour period.[7]
Toxicological considerations
This intervention stimulated research activities. And indeed, hepatotoxic substances have been identified in the plant. Researchers from the University of Hawaii at Manoa found that an alkaloid called pipermethystine (formula 1), which is primarily contained in aerial parts of the plant (stem peelings and leaves), displayed toxic effects on liver cells in vitro.[8] Flavokavain B, which is found also in the rhizome, is another compound that might contribute to toxic effects.[9] Besides this, it is known that some of the kavapyrones block several subtypes of the enzyme cytochrome P450[10], which can result in adverse interactions with other drugs concomitantly used.
Furthermore, the plant contains glutathione. Within the extracts its concentration varies depending on the lipophilicity of the applied solvent; the amount is higher in aqueous extracts. Glutathion in kava preparations is able to provide a certain protection of liver cells.[11]
Before 2002, substantial amounts of aerial parts of the kava plant were being exported to North America and Europe and obviously used for the production of commercial prepartions. For traditional use in the South Pacific, stem peelings and leaves are discarded, and only the rhizomes are used and extracted with water. This may explain why native populations that make heavy use of kava experience side effects that are mild, temporary, and confined to the skin, whereas industrialized countries that have newly adopted kava occasionally show severe, acute responses.
Outlook
The issue has long been controversial and the debate fueled by economic interests of kava-exporting nations of the Pacific Islands as well as disagreements between the medical establishment and proponents of herbal and natural medicine. The German Federal Institute for Drugs and Medical Devices (BfArM), that in 2002 temporarily inactivated kava registrations, asked the producers to provide new clinical data until June 2007, in which case a reinstitution of the kava products on the market might again be possible.[12]
A New Zealand committee who considered the issue, commented in their summary: "A comparison with paracetamol-associated hepatotoxicity, results in the conclusion that these potential risks for kava are dramatically less than that of a popular non prescription drug widely sold through grocery outlets."[13] The NZ government is currently only looking at the possibility of a suitable advisory label standard to go on kava products.
See also
References
- ^ Kevin Cassell (2005). "Fiji: A Visitor's Guide". Retrieved 2007-04-25.
- ^ Mark Blumenthal (2002). "Kava safety questioned due to case reports of liver toxicity". American Botanical Council. HerbalGram. Retrieved 2005-12-07.
- ^ One case report from 2003: Gow PJ (2003): "Fatal fulminant hepatic failure induced by a natural therapy containing kava." MJA 178(9):442-443. Fulltext
- ^ Boon HS, Wong AHC (2003). "Kava: a test case for Canada's new approach to natural health products". CMAJ. 169 (11). PMID 14638650. Retrieved 2006-07-10.
- ^ United States Centers for Disease Control and Prevention (2002). "Hepatic Toxicity Possibly Associated with Kava-Containing Products --- United States, Germany, and Switzerland, 1999—2002". Morbidity & Mortality Weekly Report. 51(47): 1065–1067. Retrieved 2005-09-16.
- ^ Center for Food Safety and Applied Nutrition (2002). "Kava-Containing Dietary Supplements May Be Associated with Severe Liver Injury". United States Food and Drug Administration. Retrieved 2005-06-16.
{{cite journal}}: Cite journal requires|journal=(help) - ^ "Kava fact sheet". Therapeutic Goods Administration, Government of Australia. April 2005. Retrieved 2006-07-10. (Download PDF 44KB)
- ^ a) Pratibha V. Nerurkar et al. (2004): "In Vitro Toxicity of Kava Alkaloid, Pipermethystine, in HepG2 Cells Compared to Kavalactones", Toxicological Sciences 79, 106-111. Fulltext.
b) Compare: Lim ST et al. (2007): "Effects of Kava Alkaloid, Pipermethystine, and Kavalactones on Oxidative Stress and Cytochrome P450 in F-344 Rats." Toxicol Sci. PMID 17329236 - ^ Jhoo JW et al. (2006): "In vitro cytotoxicity of nonpolar constituents from different parts of kava plant (Piper methysticum)", J. Agric. Food Chem. 54(8):3157-62. PMID 16608246
- ^ a) J.M. Mathews et al. (2005): "Pharmacokinetics and disposition of the kavalactone kawain: interaction with kava extract and kavalactones in vivo and in vitro", Drug. Metab. Dispos. 33(10):1555-63. PMID 16033948; Fulltext
b) J.M. Mathews et al. (2002): "Inhibition of Human Cytochrome P450 Activities by Kava Extract and Kavalactones", Drug Metab. Dispos. 30(11):1153-1157. Fulltext - ^ Whitton PA et al. (2003): “Kava lactones and the kava-kava controversy”, Phytochemistry 64(3):673-9. PMID 13679089
- ^ a) "American Botanical Council". German Government Reconsiders Kava. Retrieved 2006-05-12.
b) "University of the South Pacific". USP plays a major role in the partial lifting of the Kava ban in Germany. Retrieved 2006-05-12. - ^ New Zealand association of medical herbalists (2005). "Submission on proposed reclassification of kava as a prescription medicine" (PDF). Retrieved 2006-05-12.
Literature
- Lebot, Vincent et al. "Kava: The Pacific Drug", New Haven: Yale University Press, 1992. ISBN 0-300-05213-8
External links
- Farmers Bookshelf - Information on Tropical Crop Production in Hawaiʻi (Site has javascript navigation and kava (ʻawa) pages cannot be directly linked: click on "nutraceuticals", then "'Awa".)
- The Kava culture in Vanuatu
- Kava Ban documents
- Erowid's Kava vault
- Lycaeum: Includes list of isolated chemicals
- Kava news page
- Hawaiʻi Pacific Islands Kava Festival - An education, cultural event held in Hawaii sponsored by the nonprofit, ʻAwa Development Council
- Kava Kava Research Information Study by Ray Sahelian M.D. on Kava Kava Benefits and Side Effects