Newswise — An extract of the kudzu vine may help heavy drinkers drink less, according to a new study in the journal Alcoholism: Clinical and Experimental Research.

In a unique laboratory designed to look like a relaxing studio apartment, complete with satellite television and a beer-stocked refrigerator, 14 men and women drank fewer beers after a week's treatment with kudzu than they drank after a week's worth of placebo pills.

Of the 11 participants who completed the entire study, "eight drank fewer beers while receiving kudzu versus placebo treatment, two drank the same number of beers and one drank one more beer," according to Dr. Scott Lukas of McLean Hospital and Harvard Medical Center and colleagues.

On average, the participants drank 1 1/2 beers while on kudzu treatment during the 1 1/2-hour sessions, compared with 2 1/2 beers during the placebo treatment. They also took more but smaller sips of each beer while taking the kudzu extract, the researchers found.

Kudzu, an invasive plant introduced to the United States in 1876 and subsequently dubbed "the vine that ate the South," was used as early as A.D. 600 in China as an intoxication treatment. Recent research suggests that chemical compounds called isoflavones in the plant are the "active" ingredient in treating intoxication.

While the drinking pattern changed in kudzu users, the drinkers reported no change in their desire to drink when they began each session. Participants who took the extract in earlier studies said they felt more "tired," "floating" and "intoxicated" after one drink, suggesting that kudzu "may be prolonging or enhancing the acute effects of the first drink," Lukas says.

"Apparently, this effect is sufficient to delay or eliminate the desire to drink subsequent beers," he adds.

Lukas and colleagues note that kudzu's effects, in this sense, might be useful for reducing binge drinking or helping some people stay sober by minimizing the chance that a "slip" of having one drink will result in a full alcoholic relapse.

Studies of kudzu have been limited by the fact that "kudzu is not a pure substance like naltrexone and acamprosate," two of the drugs currently approved to treat alcoholism, says Dr. David Overstreet, an alcoholism researcher at the University of North Carolina.

"Investigators may not be willing to take the extra steps that might be necessary to conduct such a study," such as extracting the critical isoflavones from kudzu and partnering with clinical researchers, Overstreet says.

In response to these difficulties, Lukas and colleagues developed a concentrated kudzu extract with 25 percent isoflavones and developed the "natural laboratory" setting to test the extract's effects.

Participants in the study were allowed to watch television or movies in the mock studio apartment while choosing drinks from a refrigerator stocked with a favorite brand of beer and other nonalcoholic drinks.

"This scenario is analogous to a person coming home from work or school and relaxing in his or her living room," Lukas explains.

The 14 participants, allowed to open only one drink at a time, were asked to drink from a mug that they set down on special tile topped table after each sip. Unbeknownst to the drinkers, the table doubled as a special calibrated scale that allowed the researchers to measure the changing volume in the beer mug and calculate the amount of beer in each sip.

The 14 participants were heavy drinkers who reported having an average of 25 alcoholic beverages per week. None of the participants had a family history of alcoholism. Each participant was treated with kudzu and the placebo, and no side effects were found with either treatment.

The lack of side effects could, with more research, make kudzu treatment an option for teens, pregnant women "and other vulnerable populations where a lack of medication toxicity is not only desirable but also necessary," Lukas and colleagues write.

The study was supported by the National Institute on Alcohol Abuse and Alcoholism and the National Institute on Drug Abuse.

Lukas S, et al. An extract of the Chinese herbal root kudzu reduces alcohol drinking by heavy drinkers in a naturalistic setting. Alcoholism: Clinical and Experimental Research 29(5), 2005.

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CITATIONS

Alcoholism: Clinical and Experimental Research (May-2005)