Effects of energy drink ingestion on alcohol intoxication

The combined use of alcohol and "energy drinks" such as Red Bull. have become increasingly popular among youth and young adults in recent years. Users often report reduced sleepiness and increased sensations of pleasure.

In the April issue of Alcoholism: Clinical & Experimental Research, Brazilian researchers conduct the first controlled scientific study on the effects of combining alcohol with Red Bull. Results show a considerable disconnect between subjects' perceptions and objective measures of their abilities: although combined use reduces the sensation of tiredness and sleepiness, actual capabilities are significantly impaired.

"In Brazil, as in other countries, young people believe that Red Bull and other energy drinks avoid the sleepiness caused by alcoholic beverages and increase their capacity to dance all night," explained Maria Lucia O. Souza-Formigoni, associate professor in the department of psychobiology at the Federal University of Sco Paulo in Brazil and corresponding author for the study. "In fact, many night clubs offer this mix among their cocktails."

In a previous study on the use of energy drinks among Brazilians, Souza-Formigoni said that users reported greater happiness (38%), euphoria (30%), uninhibited behavior (27%), and increased physical vigor (24%). It is unclear, however, if this indicates the ability of energy drinks to reduce the depressant effects, increase the excitatory effects of alcohol, or both.

"This study appears to show us that the use of energy drinks might predispose people to abuse alcohol when its depressant effects - or at least the perception of such effects - are masked by them," said Roseli Boerngen de Lacerda, associate professor in the department of pharmacology at the Universidade Federal do Parana, Brazil.

For the current study, participants (n=26 males) were randomly assigned to one of two groups that received either 0.6 g/kg of alcohol (n=12), or 1.0 g/kg of alcohol (n=14). All participants completed three experimental sessions in random order, seven days apart: ingesting alcohol alone, energy drink alone, or alcohol and energy drink combined. At each session, researchers recorded the participants' subjective sensations of intoxication, as well as objective measures of their motor coordination, breath alcohol concentration, and visual reaction time.

Compared to the ingestion of alcohol alone, the combined ingestion of alcohol and Red Bull. significantly reduced the subjects' perception of headache, weakness, dry mouth and impairment of motor coordination. Red Bull. did not, however, significantly reduce deficits caused by alcohol on objective measures of motor coordination and visual reaction time.

"There are two key points," said Souza-Formigoni. "Although combined ingestion decreases the sensation of tiredness and sleepiness, objective measures of motor coordination showed that it cannot reduce the harmful effects of alcohol on motor coordination. In other words, the person is drunk but does not feel as drunk as he really is. 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 implications of these findings," added Boerngen, "are that this association of alcohol and energy drinks is harmful rather than beneficial, as believed by consumers. Especially because those individuals who combine alcohol and energy drinks, believing they are less impaired than reality would indicate, are actually at an increased risk for problems such as automobile accidents."

"Alcohol affects not only the motor coordination but also the capacity of decision, because it affects one important area of the brain - the prefrontal cortex," explained Souza-Formigoni. "Drunk drivers are dangerous not only because their reactions are delayed and motor coordination affected, but mainly because their capacity to evaluate the risks to which they will be exposed is also affected. People need to understand that the 'sensation' of well-being does not necessarily mean that they are unaffected by alcohol. Despite how good they may feel, they shouldn't drink and drive. Never."

Both Boerngen and Souza-Formigoni spoke of the need for further studies to test higher doses of both alcohol and energy drinks, which Souza-Formigoni is doing with the use of animal models. "We are also testing separately the different substances of energy drinks - caffeine, taurine, etc. - in combination with alcohol to determine which of them are responsible for [for what effects during] interaction."

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