Kava as a Clinical Nutrient: Promises and Challenges

Abstract

Kava beverages are typically prepared from the root of Piper methysticum. They have been consumed among Pacific Islanders for centuries. Kava extract preparations were once used as herbal drugs to treat anxiety in Europe. Kava is also marketed as a dietary supplement in the U.S. and is gaining popularity as a recreational drink in Western countries. Recent studies suggest that kava and its key phytochemicals have anti-inflammatory and anticancer effects, in addition to the well-documented neurological benefits. While its beneficial effects are widely recognized, rare hepatotoxicity had been associated with use of certain kava preparations, but there are no validations nor consistent mechanisms. Major challenges lie in the diversity of kava products and the lack of standardization, which has produced an unmet need for quality initiatives. This review aims to provide the scientific community and consumers, as well as regulatory agencies, with a broad overview on kava use and its related research. We first provide a historical background for its different uses and then discuss the current state of the research, including its chemical composition, possible mechanisms of action, and its therapeutic potential in treating inflammatory and neurological conditions, as well as cancer. We then discuss the challenges associated with kava use and research, focusing on the need for the detailed characterization of kava components and associated risks such as its reported hepatotoxicity. Lastly, given its growing popularity in clinical and recreational use, we emphasize the urgent need for quality control and quality assurance of kava products, pharmacokinetics, absorption, distribution, metabolism, excretion, and foundational pharmacology. These are essential in order to inform research into the molecular targets, cellular mechanisms, and creative use of early stage human clinical trials for designer kava modalities to inform and guide the design and execution of future randomized placebo controlled trials to maximize kava’s clinical efficacy and to minimize its risks.

A review of available herbal medicine options for the treatment of chronic insomnia

“…It is believed that a particular type of kavalactone may be capable of providing a sedative effect, called Kevain. One of the available researches about the effectiveness of kava-kava for humans reported that a daily 200mg extract of kava-kava provides significant relief from insomnia after two weeks [67]. Suanzaoren: Suanzaoren is one of the best-known herbal medicines with sedative effects in traditional Chinese medicine.…”

Management of COVID-19 on board the mixed cargo ship Aranui 5

“…Also, the negativity of the tests was explained and any rumours were ruled out. Part of the crew, for example, believed that regular ingestion of kava, a traditional slightly hallucinogenic Melanesian drink that is obtained from the roots of shrubs soaked and then squeezed [21] can prevent infection. Those who perceived themselves as immune, relaxed the preventive measures.…”

Complementary and alternative medicine

“…Kava efficacy and safety as a plant-based therapy for anxiety was reviewed by Bian ( Bian et al, 2020 ) [R] and included specific cultivar type and preparation techniques. Flavokavains A and B are associated with increased cytotoxicity and glutathione depletion in the liver.…”

“…Hepatotoxic risk may be increased due to cultivar choice (non-noble), plant part used (stems), dose (over 120 mg/day alcoholic extract), method of preparation (alcohol extraction), adulteration, concurrent ethanol ingestion, herb-drug interactions (acetaminophen). The authors conclude that more human studies are needed but risk of hepatotoxicity is relatively low overall ( Bian et al, 2020 ) [R] and included specific cultivar type and preparation techniques. Description of the use and safety of different plant parts, variations in cultivars, preparation and extraction methods, traditional use and commercial products allows the reader to grasp the complexity of kava use and the potential reasons for toxicity.…”

“…Hepatotoxic risk may be increased due to cultivar choice, plant part used, dose, method of preparation, adulteration, concurrent ethanol ingestion, herb-drug interactions. The authors conclude that more human studies are needed but risk of hepatotoxicity is relatively low overall ( Bian et al, 2020 ) [R].…”