Marco Pepe and Samantha McReavy
Kava (Piper methysticum) has long been important for many Indigenous Oceanic societies (Singh, 1992). The traditionally consumed beverage prepared from Kava has played a significant role in medicinal and ritualistic aspects of South Pacific cultures for centuries (Basch et al., 2009). The therapeutic effects associated with Kava that have been reported from both traditional use and clinical trials refer to reducing stress, anxiety, and insomnia (Singh & Singh, 2002). Such is the reputation of Kava as medicine, that its extracts are currently in high demand in the global market and are particularly advertised as over-the-counter treatment of generalized anxiety (Savage et al., 2015). In fact, Kava has been identified as one of the top ten sold herbal medications globally and is currently in high demand in the United States and Europe (Li & Zheng, 2012).
Originating in the South Pacific, Kava’s native range stretches from New Guinea to Hawaii (Briskin et al., 2001; Li & Zheng, 2012). This woody perennial shrub belonging to the family Piperaceae, can reach heights of up to 5 m (Suharano et al., 2016). The most identifiable characteristics of Kavainclude the green-purple stems and large, alternate, cordate foliage (Nelson, 2011), but it is Kava’s rhizomes that hold medicinal value due to the production of chemical compounds identified as kavapirones or kavalactones (Briskin et al., 2001). Though Kava is dioecious in nature (separate male and female plants), the vast majority of naturally occurring populations are strictly male, resulting in large groups of genetically identical colonies that have grown through rhizomes (Briskin et al., 2001; Nelson, 2011; Suharano et al., 2016). Yet, there are about 120 different varieties of Kava that have been identified (Pollock, 2009), which is an interesting occurrence given their tendency to reproduce asexually. So far, all varieties have medicinal value, so there is no greater risk of overexploitation of one variety over the other for economic gain.
Traditional and Modern Usages:
Kavawas initially cultivated by Indigenous populations to produce a beverage consumed during festivities (Briskin et al., 2001). Customary South Pacific preparation of Kava beverages involves pulverization of rhizomes to create a fine powder which is then macerated and later mixed with heated coconut milk or water (Fu et al., 2008). To optimize acquisition of the medicinal compounds, Kava plants are often harvested several years after they have reached maturity, since potency and flavor profile increase with plant age (Singh, 1992). Traditional knowledge holders can process several different healing Kava blends to confer a wide array of physiological reactions including analgesic, anxiety-reducing, anesthetic, and soporific (sweat-promoting) (Suharano et al., 2016), which have been desired not only in healing but also in social encounters.
Traditional Tongan cultures have an extensive history with Kava and use it in rituals, myths, and ceremonies (Pollock, 2009). The Marind of Southern Papua associate Kava with mysticism, preparing brews or chewing leaves for ceremonial purposes, conflict resolution, and even entertainment during specific life events (Suharano et al., 2016). In Hawaii, men are the sole attendants of Kava ceremonies in which beverages are served to presiding elders and esteemed guests, with overindulgence sometimes resulting in some toxic effects such as ataxia (loose of muscle control) (Norton, 1998). Kava’s symbolism has manifested as national icons, for example as in the flag of the Micronesian State of Pohnpei, which features a ceremonial Kava chalice (Norton, 1998).
A little history of Kava’s use in the West
Modern scientific interest in Kava emerged in the 1700s when naturalist George Forster and his father accompanied James Cook on his second Pacific voyage and brought Kava specimens to Europe for further study. Forster dubbed the plant with the Linnean binomial Piper methysticum translated as intoxicating pepper (Norton, 1998). The traditional term kava, which historically identified the customary beverage has been adapted in modern language to include the plant’s common name as well as its products (Briskin et al., 2001). Colloquially, commercial products form Kava are labelled as “Kava Root” but this is a misnomer, as the main ingredient is the rhizome.
The present uses of Kava in western societies range from recreational use as an alcohol substitute, to therapeutic uses for generalized anxiety disorder (Chua et al., 2016). There is some evidence supporting the efficacy of Kava as an over the counter herbal remedy that relate to a muscle relaxant effect, relieving of insomnia, and excessive worrying (Smith & Leiras, 2018). Due to a rapid increase in the demand for Kava products, conventional propagation techniques are unsuited because they take relatively long periods of time to produce mature plants, so laboratorypropagation methods show promise in becoming the main strategy for commercial plant production (Li & Zheng, 2012). Overharvesting this sacred crop from natural areas can restrict access to Indigenous peoples using Kava and can deplete plant populations to unhealthy levels posing a threat the species (Baker, 2011).
Kava: a natural health alternative to benzodiazepines?
Currently, benzodiazepines called benzos for short, are prescribed as the standard pharmaceutical for short-term treatment of anxiety (Basch et al., 2009), but these compounds are prone to misuse and can trigger withdrawal symptoms that worsen anxiety attacks (Arikian & Gorman, 2001). Anxiety disorders are experienced by one quarter of the American population, negatively influencing physical, social, spiritual, and cognitive aspects of daily life (Arikian & Gorman, 2001). Due to the persistent nature of clinically diagnosed anxiety, it can be compelling for patients to opt for the use of these psychoactives (Singh & Singh, 2002). Unfortunately, the utility of benzos is commonly limited to the onset of an anxiety attack, and these treatments cannot be taken daily to prevent the occurrence of anxiety (Savage et al., 2015). Impaired cognitive function, sedation, and debilitating ataxia are common side effects, which can cascade into socially significant issues such as irritability, depression, aggression, and substance abuse (Singh & Singh, 2002).
Stemming from the healing benefits of the traditional use of Kava, the potential for this plant to safely and successfully replace benzos in treating anxiety could relieve the physical, mental, social, and emotional turmoil brought forth by such disorders while reducing prescription drug dependency. The medicinal compounds in Kava function similarly to benzos, but there exists much conflicting evidence pertaining to proper dosage of Kava extracts for safe therapeutic use. Some studies suggest that Kava consumption should be used for short-term treatment of anxiety – approximately three weeks – and that it should not be taken for longer than eight weeks (Smith & Leiras, 2018), while other studies disagree (Kapalka, 2009), so further research is needed to achieve consensus.
The use of Kava is of therapeutic interest but, some adverse effects may be present if its consumption is not done under knowledgeable supervision (Baker, 2011). Prudence is needed in Western markets where Kava supplements have become very popular and consumers may be overenthusiastic about its benefits. Kava is an important medicinal plant in many Indigenous cultures so careful and responsible decisions about its conservation and use are imperative.
About the Authors
A 2010 graduate of Seneca College Horticultural and Landscape Management programs, Marco decided to further his knowledge on plant science at University of Guelph. Interests include plant cell and tissue culture, mycology, natural history, and the medicinal nature of secondary plant metabolites. Marco hopes to pursue graduate school relating to plant tissue culture in September of 2019.
Samantha McReavy is a student writer and is currently working at the Office of Research as a research communications journalist at the University of Guelph. At Guelph she also studies Nutritional and Nutraceutical Sciences and will graduate at the end of 2019. She discovered her love for knowledge translation in her third year of her undergraduate degree and has since worked to make research knowledge more accessible.