Researchers from John Hopkins University suggest that the labelling and aggressive marketing of some energy drinks, particularly towards young males, could lead to increased incidences of caffeine dependence and withdrawal in consumers.
As a stimulant, caffeine, which is present in a wealth of drinks such as tea and coffee, has been linked to both a number of possible health benefits for heart and memory as well as more detrimental impacts.
In the findings published online in the journal Drug and Alcohol Dependence, lead researcher Chad Reissig said that a large number of energy drinks had found their way to market in the last decade with a range of caffeine content.
This has varied from 50 mg to 505 mg, with the growing popularity amidst all age groups, including younger people not as habitual in their consumption of caffeine.
By comparison, the research indicated that according to manufacturer provided information, a standard can of Coca-Cola or Pepsi cola contained 34.5 mg and 38 mg respectively.
Industry wide scope
Reissig stressed that energy drinks were not solely behind any potential growth in caffeine intake and that over types of beverage may also have an impact on adverse reactions to the stimulant.
“The consumption of energy drinks may increase the risk for caffeine overdose in caffeine abstainers as well as habitual consumers of caffeine from coffee, soft drinks, and tea,” he stated. “The potential for acute caffeine toxicity due to consumption of energy drinks may be greater than other dietary sources of caffeine.”
As part of the review’s conclusions, the researchers said that there were a number of reasons to support the hypothesis linking energy drinks to concerns over higher rates of caffeine toxicity.
“Most energy drinks do not label their product with the amount of caffeine, and [in the US], are not required to display warning labels advising proper use,” the researchers said. “Many energy drinks are also marketed with claims of performance enhancing effects although, the existence and extent of such effects is subject to debate.”
The review also claimed that a lack of restriction on energy drink sales to adolescents and children, who are generally less experienced in consuming caffeine and less tolerant to any effects it may have on them, was another concern.
Reissig and his team said that concerns over energy drinks stemmed from the potential adverse consequences of higher caffeine intake on consumers.
The clinical syndrome known as caffeine intoxication was highlighted in the study as a particular concern, having been linked to a number of symptoms like nervousness, anxiety, restlessness, insomnia, gastrointestinal upset, tremors, tachycardia and psychomotor agitation.
Some studies have also suggested that the symptoms of caffeine intoxication closely resemble those of other anxiety and mood disorders, according to the review.
Caffeine withdrawal was another area of concern suggested by the review.
In more than 60 studies published over the last ten years, headaches, or varying severity, have been found to occur about 12 to 24 hours after the last dose of caffeine is taken by some consumers.
“In addition to headache, other caffeine withdrawal symptoms include tiredness/fatigue, sleepiness/drowsiness, dysphoric mood, difficulty concentrating/decreased cognitive performance, depression and irritability,” the report stated.
Caffeinated beverage safety claim
The British Soft Drink Association (BSDA), which represents a number of manufacturers in the sector, claimed that energy drinks were safe for human consumption and were strongly regulated across Europe.
“There is an extensive set of regulations regarding composition and labelling with which the industry complies,” he stated. “In fact, many companies go further and label their drinks as being not recommended for children or persons sensitive to caffeine.”
Source: Drug and Alcohol DependencePublished online, doi:10.1016/j.drugalcdep.2008.08.001
“Caffeinated energy drinks - A growing problem”Authors: C.J Reissig, et al