Get to the root of it
Understanding kava's role as a stress reliever, anxiety treatment and cancer suppressant.
f there’s one piece of advice Chengguo “Chris” Xing, Ph.D., would give you, it’s “to stress less.”
Xing, the Frank A. Duckworth Eminent Scholar Chair and a professor of medicinal chemistry in the University of Florida College of Pharmacy, sees stress as the culprit in various health conditions: insomnia, anxiety, tobacco cravings — even cancer. He’s been evaluating a natural product for its potential to help manage all of these. It’s called piper methysticum, which is better known as kava.
WHAT IS KAVA?
Kava is prepared from the root of piper methysticum, a plant native to the South Pacific Islands. It was historically used in special ceremonies, but is now a daily beverage to help its consumers relax, socialize and sleep better.
The plant’s popularity is not confined to the Pacific Islands. St. Petersburg, Florida, is known as the kava capital of the continental United States. Deriving its name from the Tongan and Marquesan word for “bitter,” kava earns its name. Consumers describe its taste at best as “earthy,” and at worst, “muddy water.”
If there’s one piece of advice Chengguo “Chris” Xing would give you,
it’s “to stress less.”
There are more than one hundred kava cultivars, which are divided into four major varieties in Vanuatu, the primary place where it’s grown: noble, non-nobles (Tudei or two-day), medicinal and wild. They have different chemical compositions and likely different pharmacology and safety profiles. Noble kava has been identified as the safest and is the most in-demand variety.
As most kava, if not all, in the continental states is imported, Xing cautions that there’s no way to know what variety you are consuming. “Very little is known about the cultivars of imported kava, how it is processed and whether there might be adulteration,” he said. “If low-quality materials come in and it is not prepared correctly, health issues could arise.”
Kava consumption is widely known for running the risk of liver damage, although there has been limited, if any, rigorous research validation. Another concern surrounding kava consumption is the fact that Vanuatu does not produce enough noble cultivars for its own needs and the products imported to the U.S. may not be from the noble cultivars.
KAVA AS A CANCER SUPRESSANT
Xing became interested in kava because of epidemiological observations showing that nations with high kava consumption — like Samoa, Vanuatu and Fiji — have lower overall cancer incidence rates, particularly in lung, colon and pancreatic cancers. Cancer rates were also observed to be lower in men than in women, which is opposite to the general trend in the rest of the world, while kava is traditionally more popular in men than women.
Stimulated by these phenomena, kava has been hypothesized to reduce cancer risk. Over the past 15 years, Xing has gradually focused his research and passion on cancer prevention. With kava as a guiding star, he is exploring how to reduce cancer risk among high-risk individuals.
To date, Xing has used various animal models demonstrating kava’s potential to prevent tumorigenesis — the development of cancerous tumors — in the lung, prostate and colon, which are three of the four cancers with the highest incidence in the U.S. His research currently focuses on lung cancer. Using a tobacco carcinogen-induced lung cancer animal model, kava demonstrated outstanding efficacy, completely blocking lung tumor development in the models under experimental conditions.
As a medicinal chemistry group, Xing’s lab has identified kava’s active ingredients, and their investigation has revealed that kava reduces DNA damage caused by tobacco carcinogen. Such research has caught the interest of the National Cancer Institute, which is funding Xing’s lab with a translational five-year, $1.8 million grant.
Xing and his colleagues have concluded a pilot kava clinical trial among smokers. The results, consistent with the data from animal models, further bolsters kava’s potential to reduce lung cancer risk among smokers. The researchers were also surprised to find the trial participants’ tobacco use and dependence decreased, likely because kava relieved their stress.
As a significant portion of cancer survivors continue to smoke after cancer treatment, the UF Health Cancer Center has funded a pilot trial to evaluate kava’s ability to reduce the risk of cancer recurrence in head and neck cancers survivors.
KAVA AS A STRESS RELIEVER AND AN ANXIOLYTIC
Kava was previously marketed as an anxiolytic agent in Europe and is currently marketed as a dietary supplement in the United States to help consumers relieve stress. Following up on kava’s tobacco cessation potential and its traditional benefit as a relaxant and sleep aid, Xing’s lab is working to identify its active ingredients in collaboration with Jay McLaughlin, Ph.D., a professor of pharmacodynamics in the UF College of Pharmacy.
Upon discovering some unique biomarkers from their pilot trial that may reduce stress and anxiety, the National Center for Complementary and Integrative Health awarded Xing’s lab $700,000 over two years, with another three years pending, to investigate the relationships of these biomarkers and kava’s anti-anxiety properties among patients with generalized anxiety disorders. If successful, an expanded trial will follow to validate the value of these biomarkers in guiding kava’s clinical use as an anxiolytic agent.
HOPES FOR THE FUTURE
“I really hope 20 to 30 years down the road we could use cancer treatment as a secondary approach,” Xing said. Cancer is complex and there are numerous risk factors, including DNA damage caused by tobacco or radiation. Xing theorizes that stress, either physiological or psychosocial, might be another major contributing factor.
The goal of Xing’s lab is to provide quantitative evidence and find a solution to reducing cancer risks — perhaps through kava. While they remain hopeful in kava’s potential, they continue to caution consumers that kava is very complex, and its improper use may cause liver damage.
Along his research journey, Xing says he’s personally benefitted from his kava research and believes all of us can do a lot to reduce our own cancer risk. He hopes that the results of his research will inspire others to build a lifestyle that reduces their cancer risk. “For instance, when I reduce my stress, my cancer risk goes down,” he said. “That’s my philosophy.”
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