By Peggy Peck, Managing Editor, MedPage Today
Reviewed by Robert Jasmer, MD; Assistant Professor of Medicine, University of California, San Francisco
March 27, 2006
SAO PAULO, Brazil, March 27 - Mixing alcohol with energy drinks like Red Bull masks some of the subjective feelings of intoxication, but the imbibers remain just as drunk as those who take their liquor straight or with traditional mixers.
So said researchers here who tested 26 healthy men with a variety of libations and reported their findings in the April issue of Alcoholism: Clinical and Experimental Research.
The investigators evaluated breath alcohol concentration, subjective impressions of intoxication and objective measures of coordination and visual reaction time after volunteers drank Red Bull alone or Red Bull plus vodka, or straight vodka.
After drinking the Red Bull plus vodka cocktails the volunteers said they felt less intoxicated than when they drank straight vodka, but objective measures failed to confirm this subjective assessment, said Maria Lucia O. Souza-Formigoni, Ph.D., a psychobiologist and colleagues at the Federal University of Sao Paulo Sino.
The Red Bull vodka mixture was associated with a decreased sense of tiredness and sleepiness, but "objective measures of motor coordination showed that it cannot reduce the harmful effects of alcohol on motor coordination," wrote Dr. Souza-Formigoni and colleagues.
"In other words, the person is drunk but does not feel as drunk as he really is," they added. "The second important point is that many users reported using energy drinks to reduce a not-so-pleasant taste of alcoholic beverages, which could dangerously increase the amount (as well as the speed of ingestion) of alcoholic beverages."
The volunteers, all healthy men with a mean age of 23, who reported a history of moderate alcohol consumption, were randomly assigned to two groups on the basis of on alcohol ingested. Twelve men were assigned to drinks containing 0.6g/kg of vodka and 14 to a group that received 1.0 g/kg of alcohol.
The men each completed three testing sessions seven days apart. At each session the men first consumed a McDonald's Big Mac, French fries, and a soft drink 45 minutes before downing the test drinks. They were asked to finish the drinks in 10 to 20 minutes.
At the end of each session the volunteers were given a snack as well as coffee and were then taken home by taxi.
Breath tests were done before ingesting the drinks and then at intervals 15, 30, 60, 90, 120 and 150 minutes after finishing the drinks. Subjective evaluations were done at 30 and 120 minutes after drinking.
Motor coordination was evaluated at 30 and 120 minutes using a standard peg board test. Visual reaction time was evaluated at 30 and 120 minute intervals using PSS CogReHab 95 software that measures the time it takes to track a moving yellow square on a computer monitor.
As might be expected, breath alcohol concentrations were higher among men who consumed the 1.0 g/kg drinks. The peak breath alcohol concentrations occurred 30 minutes after ingesting 0.6 g/kg and 60 minutes after consuming 1.0 g/kg drinks whether the alcohol was ingested as a "straight" drink or mixed with Red Bull.
The authors concluded that although it is possible that higher concentrations of energy drinks, which contain high levels of caffeine, might counteract some effects of alcohol, that was not demonstrated in this study.
But because the energy drinks leave the drinkers feeling less intoxicated, mixing alcohol with energy drinks could increase the probability that such drinkers will become involved in accidents, the investigators said.Primary source: Alcoholism: Clinical and Experimental Research
Source reference: Ferreira S.E. et al "Effects of Energy Drink Ingestion on Alcohol Intoxication" Alchol Clin Exp Res 2006; 30:1-8