In the South Pacific Islands where the root of piper methysticum, or kava, is consumed daily as a beverage, cancer rates are low.
The South Pacific Islands of Vanuatu, Fiji and Western Samoa have a cancer occurrence rate 20 to 30 percent lower than in countries with no kava consumption, according to studies published in the year 2000.
Similarly, despite smoking rates comparable to those of the U.S., the occurrence of lung cancer in Fiji is just 5 to 10 percent that of the U.S. lung cancer occurrence rate.
The hypothesis that kava may slow the development of lung and colon cancer is one that researcher Chengguo Xing, Ph.D. in the University of Minnesota’s College of Pharmacy and Masonic Cancer Center is investigating. His research is currently supported by a $1 million grant award from the National Institutes of Health.
“Our preliminary results show that kava consumption seems to reduce the number of tumors occurring as a result of tobacco carcinogen-induced lung cancer,” said Xing. “This is a promising find.”
It opens up the possibility of giving kava to current or former smokers to reduce their risk of developing lung cancer. (Smoking increases the risk of developing lung cancer 13 times for women and 23 times for men.)
However, kava has a not-so-positive face as well: Commercially sold kava is significantly more toxic than the traditional kava drink and in Europe – where kava had previously been used to treat anxiety – the product was pulled from the market when it was found to be associated with severe liver problems such as hepatotoxicity (liver toxicity). Perplexingly, native kava drinkers were not found to experience the same liver problems.
“This is a multilayer challenge,” said Xing. “We are not only being challenged to prove that kava is effective, we’re also being challenged by its potential adverse effects. We need to learn what is responsible for its chemoprevention and what is toxic, and whether these two can be separated.”
With his research, Xing ultimately aims to provide guidance for the standardization of kava products on the market and help clear up the confusion surrounding kava by getting to the root of kava’s chemopreventive property and its adverse risk.