Published online 18 November 2010 | Nature | doi:10.1038/news.2010.622

News: Explainer

US clamp-down on alcoholic energy drinks

Food and Drug Administration warns companies over drinks mixing alcohol with caffeine.

alcoholic and caffeine drinksConsumption of drinks such as Four Loko, which combines high-alcohol beer with caffeine, has soared on US campuses.US Food and Drug Administration

The United States has effectively banned drinks manufactured to contain both alcohol and caffeine. On 17 November, the US Food and Drug Administration (FDA) sent warning letters to four companies saying that they were breaking food safety law by marketing caffeinated alcoholic beverages (CABs). Drinks such as Four Loko, which combine caffeine with high-alcohol beer, have become hugely popular on US university campuses. But the caffeine in these drinks is an "unsafe food additive", the agency wrote. It has given the companies 15 days to remove the caffeine from their products or risk having the FDA seize them, or block their sale with a court-ordered injunction.

What led the FDA to take this step?

A group of 18 state attorneys general asked the agency to review the safety of CABs in September 2009. They were concerned about an increasing number of incidents, especially on university campuses, in which young people have become seriously ill after drinking CABs.

The FDA launched its safety review last November. It asked nearly 30 makers of the beverages for data supporting their safety, and conducted a comprehensive review of the scientific literature on the co-consumption of caffeine and alcohol.

The four companies that have now received warning letters were chosen because of the high caffeine content of their drinks and because of their advertising, which uses the caffeine addition as a selling point. But FDA deputy commissioner Joshua Sharfstein says that he expects the warning letters "to be read across the industry".

Is the FDA also targeting age-old stalwarts such as rum and Coke?

Not if they are mixed on site by a bartender, or at home for that matter. CABs have been singled out because they are manufactured to contain caffeine and alcohol, meaning that the FDA has the legal authority to demand that the mixture be "generally recognized as safe" by scientific experts. There is no such consensus.

What's more, the sheer quantity of alcohol and caffeine in many CABs dwarfs that in a standard rum and Coke. Four Loko, the most popular CAB in the United States, is sold in 23.5-ounce (almost 0.7 litres) containers that are 12% alcohol by volume. One can contains about the same amount of alcohol as an entire bottle of wine — along with 260 milligrams of caffeine, the equivalent of two or three standard cups of coffee. By contrast, a typical serving of rum and Coke contains one unit of alcohol (equivalent to a small glass of wine) and just 11 milligrams of caffeine.

What evidence is there for the mix of caffeine and alcohol being dangerous?

Research on CABs is young, but several recent studies suggest that subjects who mix alcohol and high-caffeine energy drinks are more likely to engage in risk-taking behaviour.

In one 2006 survey of 4,271 students from ten universities in North Carolina, some 24% said they had consumed alcohol mixed with energy drinks in the previous 30 days1. This group was significantly more likely than other students to engage in binge drinking, and got drunk twice as often. Even after adjusting for the amount of alcohol they consumed, this group was at increased risk of alcohol-related consequences including being taken advantage of sexually, taking advantage of another person sexually, riding with an intoxicated driver, being physically hurt or injured, and requiring medical treatment.

In another study published this year2, researchers interviewed 802 people as they left bars in a university district, and measured their breath-alcohol concentrations. Those who had consumed alcohol mixed with energy drinks were three times more likely to be leaving the bar highly intoxicated, and four times more likely to be intending to drive, compared to other patrons.

Exactly how caffeine and alcohol interact in the brain isn't well understood, but it is known that caffeine can mask the depressant effects of alcohol when the two are drunk together3. This makes physiological sense: alcohol's soporific effect stems from the fact that it boosts levels of adenosine in the brain, whereas caffeine blocks adenosine receptors. People who mix the two can therefore end up 'wide awake drunk' and may be more likely to underestimate how intoxicated they are.

Are other countries clamping down on CABs?

Some are. Iceland, Norway, Denmark and Turkey have limited the amount of caffeine allowed in any energy drink to 150 milligrams per litre. In August, a Scottish parliamentary alcohol commission recommended the same limit for CABs.

Where does the 150 milligram cap come from?

It seems to be arbitrary. "Countries have had difficulty settling on that cap, because it's not clear on what research that number is based," says Mary Claire O'Brien, an associate professor of emergency medicine at Wake Forest University Baptist Medical Center in Winston-Salem, North Carolina, and lead author of the study that surveyed the university students in North Carolina. "Until it's determined with hard science what amount is safe, no amount is safe — at least in a manufactured product. That's the part the FDA has some control over."

What difference is the FDA's letter likely to make?

The reaction from the recipients has been mixed. Phusion Projects, the Chicago, Illinois-based maker of Four Loko, said on 16 November — even before the FDA sent its letters - that it would remove the caffeine from Four Loko. But on 17 November, Michael Michail, president of United Brands in San Diego, California, said that his company "disagrees with the FDA's action and rationale" and that it will "continue to produce quality products that meet the demands of our loyal adult consumers".

Rhonda Kallman, founder and CEO of New Century Brewing Company in Boston, Massachusetts, said on 18 November that she was "shocked" by the contents of the warning letter and that she will need to speak to the FDA for help interpreting it and deciding on a course of action. The fourth company, Charge Beverages of Portland, Oregon, could not be reached for comment on short notice.

Even if the FDA succeeds in stopping the sale of CABs, people may just mix strong caffeine and alcohol drinks for themselves. Before CABs soared to popularity, young people were mixing potent brews (sometimes known as VodBombs or DVRs) of vodka and Red Bull, the caffeine-packed, non-alcoholic energy drink. Another college favourite is the Jägerbomb, in which Red Bull is mixed with the German liqueur Jägermeister, which is 35% alcohol by volume. 

  • References

    1. O'Brien, M. C. et al. Acad. Emerg. Med. 15, 453-460 (2008). | PubMed |
    2. Thombs, D. L. et al. Add. Behav. 35, 325-30 (2010).
    3. Ferreira, S. E. et al. Alcohol Clin. Exp. Res. 30, 598-605 (2006). | PubMed |
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