There's more evidence that mixing alcohol and energy drinks like Red Bull, Rock Star and Monster is a bad idea. A new study finds it can boost the risk of binge drinking.
Australian researchers found people had a greater urge to keep drinking after downing a beverage containing both alcohol and an energy drink, compared to alcohol alone, according to the report published in Alcoholism: Clinical and Experimental Research.
It’s possible that caffeine may be amplifying the high that comes with alcohol, said Rebecca McKetin, the study’s lead author and a fellow at the Australian National University’s Centre for Research on Aging, Health and Well-Being.
Whatever the mechanism is, “our findings suggest that energy drinks may increase the risk of people drinking to intoxication and consequently increase the risk of alcohol-related problems like drunk driving and alcohol-fueled violence,” McKetin said.
McKetin and her co-author, Alice Coen, rounded up 75 volunteers, aged 18 to 30, and asked them to fill out a questionnaire that rated their urge to drink. Then the volunteers were randomly assigned to receive either an energy drink combined with fruit juice and two shots of vodka or soda water and fruit juice mixed with two shots of vodka.
Questionnaires filled out 20 minutes after the cocktails were downed showed that volunteers who had consumed the combination of alcohol and energy drinks had a greater urge to keep drinking.
What’s intriguing about the new study is that it focused on the early, or “priming,” effects of caffeine and alcohol, said Dr. Larissa Mooney, an addiction psychiatrist and an assistant professor of psychiatry at University of California, Los Angeles. “It shows that something is happening to trigger a desire to want more, and that that happens pretty early on, after the first drink is consumed.”
While the increase in the urge to drink was moderate, “it adds to the larger conversation about alcohol and energy drinks,” said David Jernigan, an associate professor at the Johns Hopkins Bloomberg School of Public Health. “Particularly for young people, mixing alcohol with high levels of caffeine, from all we can tell, may lead to a greater likelihood of bad things happening.”
Dr. Charles O’Brien, a professor of psychiatry at the University of Pennsylvania and director of the Center for Studies in Addiction, agreed. “The real risk of this combination is that people feel they aren’t drunk when they are,” he said. “That’s because caffeine wards off the sedation that normally comes when you drink.”
In a statement, the American Beverage Association noted the study doesn't establish a link between energy drinks and increased alcohol consumption.
"Rather, it measures how people feel and not what they actually do," according to the ABA statement. "Importantly, ABA member companies who manufacture or distribute energy drinks in the United States voluntarily adhere to responsible labeling and marketing guidelines that do not allow energy drink labels to promote mixing with alcohol nor make any claims that the consumption of alcohol together with energy drinks counteracts the effects of alcohol.”
Linda Carroll is a regular contributor to NBCNews.com and TODAY.com. She is co-author of "The Concussion Crisis: Anatomy of a Silent Epidemic”and the recently released “Duel for the Crown: Affirmed, Alydar, and Racing’s Greatest Rivalry”
This story was updated to include the statement from the American Beverage Association