Kava (=Piper methysticum)
Kava (Piper methysticum) (Piper Latin for "pepper", methysticum Greek for "intoxicating") is an ancient crop of the western Pacific. Other names for kava tree include 'awa (Hawaii), 'ava (Samoa), yaqona (Fiji), sakau (Pohnpei) and kava (Papua). The word kava is used to refer both to the plant and the beverage produced from its roots. Kava is a tranquilizer primarily consumed to relax without disrupting mental clarity. Its active ingredients are called kavalactones. In some parts of the Western World, kava extract is marketed as herbal medicine against stress, insomnia, and anxiety. A Cochrane Collaboration systematic review of its evidence concluded that it was likely to be more effective than placebo at treating short-term social anxiety. Safety concerns have been raised over liver toxicity, although research indicates that this may be largely due to the use of stems and leaves in supplements, which were not used indigeneously.
Scientific classification:
-Kingdom: Plantae
-Family: Piperaceae
-Species: Piper Methysticum
Pharmacology:
Kava's active principal ingredients are the kava lactones, of which at least 15 have been identified and are all considered psychoactive. Only six of them produce noticeable effects, and their concentrations in kava plants vary. Different ratios can produce different effects. Kava has some abuse potential and some experts recommend cycling use over 1 to 3 months.
Effects of kavalactones include mild sedation, a slight numbing of the gums and mouth, and vivid dreams. Kava has been reported to improve cognitive performance and promote a cheerful mood. Muscle relaxant, anaesthetic, anticonvulsive and anxiolytic effects are thought to result from direct interactions of kavalactones with voltage-gated ion channels. Research currently suggests that kavalactones potentiate GABAA activity but do not alter levels of dopamine and serotonin in the CNS. Heavy, long-term kava use does not cause any reduction of ability in saccade and cognitive tests but is associated with elevated liver enzymes.
Desmethoxyyangonin, one of the six major kavalactones, is a reversible MAO-B inhibitor (Ki 280 nM) and is able to increase dopamine levels in the nucleus accumbens. This finding might correspond to the slightly euphoric action of kava.
Kavain in both enantiomeric forms inhibit the reuptake of noradrenalin at the transporter (NAT), but not of serotonin (SERT). An elevated extracellular NA level in the brain may account for the reported enhancement of attention and focus.
Effects:
A moderately potent kava drink causes effects within 20–30 minutes that last for about two and a half hours, but can be felt for up to eight hours. Because of this, it is recommended to space out servings about fifteen minutes apart. Some report longer term effects up to two days after ingestion, including mental clarity, patience, and an ease of acceptance. The effects of kava are most often compared to alcohol, or a large dose of valium.
The sensations, in order of appearance, are slight tongue and lip numbing (the lips and skin surrounding may appear unusually pale); mildly talkative and sociable behavior; clear thinking; anxiolytic (calming) effects; relaxed muscles; and a very euphoric sense of well-being. The numbing of the mouth is caused by the two kava lactones kavain and dihydrokavain which cause the contraction of the blood vessels in these areas acting as a local topical anesthetic. These anesthetics can also make one's stomach feel numb. Sometimes this feeling has been mistaken for nausea. Some report that caffeine, consumed in moderation in conjunction with kava can significantly increase mental alertness.
A potent drink results in a faster onset with a lack of stimulation, the user's eyes become sensitive to light, they soon become somnolent and then have deep, dreamless sleep within 30 minutes. Sleep is often restful and there are pronounced periods of sleepiness correlating to the amount and potency of kava consumed. Unlike alcohol-induced sleep, after wakening the drinker does not experience any mental or physical after effects. However, this sleep has been reported as extremely restful and the user often wakes up more stimulated than he or she normally would. Although excessive consumption of exceptionally potent brew has been known to cause pronounced sleepiness into the next day. Although heavy doses can cause deep dreamless sleep, it is reported that many people experience lighter sleep and rather vivid dreams after drinking moderate amounts of kava.
After thousands of years of use by the Polynesians and decades of research in Europe and the U.S., the traditional use of kava root has never been found to have any addictive or permanent adverse effects. Users do not develop a tolerance. While small doses of kava have been shown to slightly improve memory and cognition, large amounts at one time have been shown to cause intoxication. In Utah, California, and Hawaii there have been cases where people were charged with driving under the influence of alcohol after drinking a significant amount of kava (eight cups or more) although some of them were acquitted due to the laws not being broad enough to cover kava consumption.
Fresh kava root contains on average 80% water. Dried root contains approximately 43% starch, 20% fibers, 15% kava lactones, 12% water, 3.2% sugars, 3.6% proteins, and 3.2% minerals. Kava lactone content is greatest in the roots and decreases higher up the plant.
Relative concentrations of 15%, 10% and 5% have been observed in the root, stump, and basal stems, respectively.
The mature roots of the kava plant are harvested after a minimum of 4 years (at least five years ideally) for peak kavalactone content. Most kava tree produce around 50 kgs (110 lbs) of root when they are harvested. Kava root is classified into two categories: crown root (or chips) and lateral root. Crown roots are the large diameter pieces that look like big (1.5 inch to 5 inches diameter) wooden poker chips. Most kava plants consist of approximately 80% crown root upon harvesting. Lateral roots
are smaller diameter roots that look more like a typical root. A mature kava plant is approximately 20% lateral roots. Kava lateral roots have the highest content of kavalactones in the kava plant. "Waka" grade kava is kava that is made of lateral roots only.Basic research on anti cancer potential:
On 15 February 2006, the Fiji Times and Fiji Live reported that researchers at the University of Aberdeen in Scotland and the Laboratoire de Biologie Moleculaire du Cancer in Luxembourg had discovered that kava may treat ovarian cancer and leukemia. Kava compounds inhibited the activation of a nuclear factor that led to the growth of cancer cells. The Aberdeen University researchers published in the journal The South Pacific Journal of Natural Science that kava methanol extracts had been shown to kill leukemia and ovarian cancer cells in test tubes. The kava compounds were shown to target only cancerous cells; no healthy cells were harmed. This may help explain why kava consumption is correlated with decreased incidence of cancer.
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.
Side effects and safety:
Skin rashes:
Chronic and heavy use of kava for a period of three months or more has occasionally been reported to cause a scaly, yellow skin rash and an eye irritation that disappears after discontinuation of the herb. The rash resembles one brought on by a niacin (Vitamin B3) deficiency; however, a double-blind, placebo-controlled study showed no change in the rash after niacin supplementation. The 29 Tonga islanders who presented with the rash after heavy kava consumption--more than 900 g/week--were given either 100 mg of oral niacinamide or placebo. No statistically significant improvement was seen in the supplementing group, suggesting niacin deficiency may not cause the rash, which is more characteristic of an acquired ichthyosis. Until more is known, however, people taking kava regularly may also wish to take a multivitamin with at least 50 to 100 mg of niacin daily.
Liver damage incidents and regulation:
In 2001 concerns were raised about the safety of commercial kava products. There have been allegations of severe liver toxicity, including liver failure in some people who had used dietary supplements containing kava extract (but not in anyone who had drunk kava the traditional way). Out of the 50 people worldwide taking kava pills and extracts that have had some type of problem, almost all of them had been mixing them with alcohol and pills that could have effects on the liver. The fact that different kava strains have slightly different chemical composition made testing for toxicity difficult as well.
The possibility of liver damage consequently prompted action of many regulatory agencies in European 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 medicine products. Kava is banned in Switzerland, France, Germany and The Netherlands. The health agency of Canada issued a stop-sale order for kava in 2002. But legislation in 2004 made the legal status of kava uncertain. The United States CDC has released a report 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). The Australian Therapeutic Goods Administration has recommended that no more than 250 mg of kavalactones be taken in a 24 hour period. According to the Medicines Control Agency in the U.K., there is no safe dose of kava, as there is no way to predict which individuals would have adverse reactions.
Toxicology of pill from kava extracts with stems and leaves:
The legal intervention of several countries stimulated research, and hepatotoxic substances were found in the stems and leaves of the plant. Researchers from the University of Hawaii at Manoa found that an alkaloid called pipermethystine (formula 1), contained in stem peelings and leaves but not in the roots, had toxic effects on liver cells in vitro and in vivo. In rats fed with 10 mg/kg pipermethystine for two weeks, indications of hepatic toxicity were found. Comparable signs of toxicity were not detected with kava rhizome extracts (100 mg/kg, 2 weeks), (73 mg/kg, 3 months).
Flavokavain B, found in the plant's rhizome (large horizontal underground stem), may also contribute to toxic effects. And, it is known that some of the kavapyrones block several subtypes of the enzyme cytochrome P450, which can result in adverse interactions with other drugs used concomitantly.
Hawaiian researchers learned from a trader in Fijian kava that European pharmaceutical companies eagerly bought up the stem and leaves peelings when demand for kava extract soared in Europe in 2000 and 2001. 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 pill extracts. 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.
A medical conference in Fiji determined that the high concentrations of kava resins in pill form extracts alone could have been the culprit for the liver damage incidents.
Toxicity of traditional kava beverage preparations:
Kava has been consumed heavily as a beverage in the south Pacific for around 3000 years with no reports of liver problems. One study has reported that when kava preparations are made with the root of the plant no toxicity is found. However, in one study some changes in liver function are noticed. The effects are temporary and reversible when discontinuing kava use. Although kava root does not cause liver toxicity, there is evidence of health concerns among heavy drinkers, including poor nutrition and a rise in liver enzymes.
The plant also contains glutathione. In extracts its concentration varies depending on the lipophilicity of the applied solvent; the amount is higher in aqueous extracts. Glutathione in kava beverage preparations is able to provide a certain protection of liver cells. However, kava extracts in pill form will not have the glutathione in it to help protect the liver.
Allergy:
Literature suggests that 0.5% of people that take kava have an allergic reaction to it. Allergic reactions are usually mild and include itchy skin or itchy throat, and hives on the skin usually prevalent on the user's belly region. If someone has an allergy to any relative of the pepper family, such as black pepper, they have a higher chance of having a kava allergy.
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