A new study on the effects of the traditional Pacific Island drink known as kava — or 'awa — found unexplained changes in the livers of kava drinkers, who were mostly Tongan men.

Researchers at the University of Hawai'i medical school's complementary and alternative medicine department who conducted the study stressed that the results do not show liver damage and more research may be needed.

The results of the clinical, observational study indicated a higher level of one liver enzyme sometimes linked with liver toxicity, but no significant change in other enzymes sometimes associated with toxicity.

"There's some evidence of something happening in the liver," said Dr. Janet Onopa, an assistant professor of medicine at the John A. Burns School of Medicine who analyzed the data and reviewed the lab reports. "But it doesn't seem like anything catastrophic."

The study is published in the June-August issue of Clinical Toxicology — the journal of the American Academy of Clinical Toxicology. It comes after Hawai'i's kava harvest fell 58 percent in 2003 when Singapore, Germany, Canada, the United Kingdom and other countries banned pharmaceutical sales of highly concentrated kava dietary supplements that had been linked to liver damage and death.

The U.S. Food and Drug Administration did not ban kava supplements but issued an advisory warning of the potential risk of severe liver injury.

In 2004, a team of UH scientists theorized that the problem in the dietary supplements came from the stem peelings and leaves of kava plants, which are not used in kava drinks.

Some historians believe that the first Polynesian voyagers brought kava to Hawai'i, where it's known as 'awa to both Hawaiians and Samoans.

TONGAN TRADITION

For centuries, Tongans and other island cultures have been making kava out of the roots and root stumps of the Piper methysticum, or intoxicating pepper shrub, by turning it into powder and then mixing it with water.

Regular kava or 'awa users insist that it relaxes both the muscles and mind without causing the kind of inebriation associated with alcohol.

Westerners often indelicately compare the taste of kava to dirty water and usually notice a numbing of the lips and mouth.

"New people — when they drink it — they feel that way," said Misi Napaa, a 30-year-old rock wall mason, as he mixed up a batch of kava last week for the First United Methodist Church's regular Wednesday night "kava circle" of Tongan men.

In their study, UH medical school researchers took blood samples from 31 regular kava drinkers from O'ahu and compared them to blood samples from 31 other people on O'ahu who never drank kava.

Ninety percent of the kava drinkers were men and 74 percent of them were Tongan. In the control group of non-kava drinkers, 81 percent were women and 68 percent were Tongan.

The blood work revealed elevated levels of the liver enzyme GGT — or gamma-glutamyl transpeptidase — in 65 percent of the kava drinkers. The levels of GGT increased with increased kava consumption.

In the control group, high GGT levels were only seen in 26 percent of the non-drinkers.

"We don't know exactly what a high GGT in and of itself means," Onopa said. "It's possible that kava just induced that enzyme without doing any liver damage."

The UH study is unlikely to have any effect on the kava-drinking habits of Tongans on O'ahu, who trace the tradition back thousands of years.

"People think that kava is like alcohol. It's not," said the Rev. Eddie Kelemeni, senior pastor at First United Methodist Church on Beretania Street. "I used to drink beer and alcohol in my younger days but not anymore. I don't care how much kava I drink. I don't get drunk."

More than half of the church's 500 parishoners are Tongan, Kelemeni said, and Tongan men gather in kava circles at First United Methodist at least three times a week.

"The most important part is not the drinking of the kava," Kelemeni said. "It's the conversations of the group, all of the storytelling."

GENESIS OF THE STUDY

The idea for the UH medical school study began with Pakieli Kaufusi, a junior researcher in the department of tropical medicine.

Kaufusi grew up in Tonga watching his father drink kava repeatedly from a 48-ounce "lion cup." Kaufusi estimates his father consumed at least 1,000 kava drinks from the lion cup each month.

"They would start drinking at 7 o'clock at night and finish at 2 o'clock in the morning," Kaufusi said. "A lot of Tongans consume kava daily in very large amounts. If this is really true that kava is bad for your liver, then all of the Tongan people should have died by now of liver disease."

The head of the UH study, Amy C. Brown, an associate professor of medicine in the medical school's complementary and alternative medicine department, said she originally wanted to compare liver results from an equal amount of drinkers and non-kava drinkers from most ethnic groups on O'ahu.

But the overwhelming majority of kava drinkers they found in churches and informal kava circles were Tongan, with a few Caucasian drinkers frequenting a now-defunct kava bar on Kapahulu Avenue.

"It was difficult to find Asian or Caucasian volunteers," Brown said. "But there were 30, 40, 50 Tongans per night around a kava bowl in kava drinking circles."

H.C. "Skip" Bittenbender, a specialist with the UH College of Tropical Agriculture and Human Resources, is helping to organize the fourth Hawai'i Pacific Islands Kava Festival at UH on Oct. 6 and also leads his own kava circle Friday afternoons in his UH lab.

Most of the people who drink kava with Bittenbender are Caucasian graduate students and professors just like him, Bittenbender said.

"It's open to anyone who wants to join us on a Friday afternoon," Bittenbender said, "but unfortunately, there aren't any Tongans and only occasionally some Hawaiians."

Bittenbender grows kava plants in his garden in St. Louis Heights and drinks kava at least five nights per week.

"It has a nice calming effect," he said. "Kava is not known to provide a hangover and it's much more subtle than alcohol."

'VERY MELLOW'

Last week, Napaa arrived at the First United Methodist Church at about 8:45 p.m. with two Ziploc bags filled with kava powder from Tonga that he bought in Kalihi.

Napaa poured the ingredients from one bag into a nylon strainer and continuously crushed and twisted the contents under flowing water in the church's kitchen until it produced five gallons of brown-colored fluid.

Outside, in the church's lanai, 10 men from Tonga sat with individual coconut ipu kava bowls in front of them, waiting for Napaa to pour the kava into the huge kumete bowl sitting on a plastic table.

Kaliloa, a 65-year-old "talking chief" from Tonga, said it would take the men about half an hour to finish the first 5-gallon batch before sending Napaa back into the kitchen.

"Kava is very important for the people," Kaliloa said. "When we finish church, we come over here for talk story."

William Langi, 72, of Kalihi, regularly sends multiple packages of powdered kava to his grandsons attending college at the University of Maryland and prefers they drink kava to beer.

"Alcohol — go up, up, up, too much noise," Langi said. "Kava, no trouble. Very mellow."

Even with the high GGT enzyme results of the UH study, the men said they aren't about to change their kava-drinking habits.

But Brown, the lead author of the study, said heavy kava drinkers might consider getting their liver functions tested.

"You want your liver profile to be normal," she said. "If something is causing that to be abnormal, then you should discuss it with your doctor and have your doctor run a liver profile. Then take your doctor's advice."

Reach Dan Nakaso at dnakaso@honoluluadvertiser.com.