Root May Help Reduce the Risk of Lung Cancer in Smokers Say University Researchers

New research from the University of Minnesota College of Pharmacy and Masonic Cancer Center has found that consumption of the root of Piper methysticum, or kava, a plant native to the South Pacific Islands, may prevent the development of tobacco smoke-induced lung cancer.

In addition, the research team has identified the naturally occurring components of kava that appear responsible for all the cancer-preventative benefits. By using a patent-pending blend of these active kava ingredients, the research team was also able to avoid liver damage, a rare side effect previously associated with various commercially available kava-containing dietary supplements.

In the latest study, the University of Minnesota research team found daily consumption of a kava-derived dietary supplement prevented the formation of 99 percent of tumors in a mouse lung tumorigenesis model that is routinely used in predicting lung cancer behavior in humans. The unprecedented level of tumor prevention was coupled with the finding that some mice developed no tumors at all. DNA damage resulting from tobacco carcinogens was also significantly reduced by way of prevention, providing a clue to what is potentially behind kava's effectiveness.

The findings open up the future possibility of health care professionals recommending or prescribing kava-derived products in the form of dietary supplements or drugs for current tobacco smokers to reduce their risk of developing lung cancer. According to the Centers for Disease Control and Prevention, smoking increases the risk of developing lung cancer 13-fold for women and 23-fold for men.

The research may also help explain the low rate of cancer incidence where kava is traditionally consumed. Rates of cancer in the South Pacific Islands of Vanuatu, Fiji and Western Samoa are dramatically lower than those in countries with no kava consumption. Similarly, despite tobacco smoking rates comparable to those of the United States, the occurrence of lung cancer in Fiji is just 5 to 10 percent of the U.S. lung cancer occurrence rate.

However, not all commercially available kava products on the market today are equal and many may carry the risk of liver injury.

In Europe, where kava had been routinely used to treat anxiety, kava products were temporarily pulled from the market after being linked to liver problems. Many factors have been hypothesized to contribute to the rare problems, and although a definitive cause has not been identified, current products in the market typically carry a liver injury warning. Prior to liver toxicity concerns, Hawaii served as one of the largest sources of commercially available kava.

"I wouldn't recommend using kava supplements on the market today with the hopes of receiving cancer prevention benefits," said Chengguo Xing, Ph.D., an associate professor of medicinal chemistry at the University of Minnesota College of Pharmacy and a member of Masonic Cancer Center. "Although occasional use of currently available kava supplements is likely to have a low risk of liver injury, they may not safely provide the intended chemopreventative benefits."

Preliminary data from University of Minnesota has identified the potential compound behind kava-related liver problems and human clinical trials for the new, patent-pending kava supplement enriched with cancer-preventative benefits alone are planned. The University of Minnesota research team is also pursuing development of kava-derived drugs that may aid in both the prevention and treatment of other types of cancers.

The findings are published in the journal Cancer Prevention Research.