The number of emergency department visits involving energy drinks doubled between 2007 and 2011, from 10,068 visits to 20,783.
The research team, including João Breda of the World Health Organization (WHO) Regional Office for Europe, publish their review in the journal Frontiers in Public Health.
Sales of energy drinks have soared in recent years. In the US, sales increased by 60% between 2008 and 2012. It is estimated that 68% of adolescents, 30% of adults and 18% of children under the age of 10 consume the beverages.
But increasing consumption of energy drinks has caused an increase in adverse health effects. Last year, a report from the Substance Abuse and Mental Health Services Administration (SAMHSA) revealed that the number of emergency department visits involving energy drinks doubled between 2007 and 2011, from 10,068 visits to 20,783.
Such figures have raised concern among the general public and scientific community about the safety of energy drinks, according to the researchers. "Despite this," they add, "there have been limited rigorous studies carried out in Europe on the risks associated with the increase in energy drink consumption, particularly among young people."
As such, the team reviewed all available research looking at the health risks of energy drink consumption and made a number of suggestions to help reduce these risks.
The adverse health effects linked to excess energy drink consumption
Caffeine is the main ingredient in energy drinks, and the one that causes most health concerns. A single can contains as much as 500 mg of caffeine - the equivalent to five cups of coffee.
The team notes that energy drinks, however, are more likely to cause caffeine intoxication than coffee.
"Although some types of coffee can have caffeine levels comparable to energy drinks, coffee is typically consumed hot and consequently more slowly. Further, the proliferation of new brands of energy drinks has included some brands, which contain extreme caffeine levels much higher than mainstream brands as they try to establish themselves in the market."
They point out that a study from the European Food Safety Authority (EFSA) found that energy drinks contribute to 43% of total caffeine intake in children, 13% in adolescents and 8% in adults - numbers that are a cause for concern.
Studies included in the team's review claim that excess caffeine intake can lead to numerous health problems, including hypertension, heart palpitations, nausea and vomiting, psychosis, convulsions and even death.
Earlier this year, Medical News Today reported on a study claiming both sports drinks and energy drinks may lead to unhealthy behaviors in adolescents. The researchers note:
"Consumption of energy drinks among adolescents is associated with other potentially negative health and behavioral outcomes such as sensation seeking, use of tobacco and other harmful substances, and binge drinking is associated with a greater risk for depression and injuries that require medical treatment."
Energy drinks and alcohol: a deadly mix
A major concern, the researchers say, is the number of young adults who mix energy drinks with alcohol. The EFSA study found that this occurs among 71% of adults aged 18-29 who consume energy drinks.
"There is an increasing amount of research linking energy drink consumption with high-risk behavior, particularly when combined with alcohol," the authors note.
Last year, for example, MNT reported on a study claiming that mixing alcohol with energy drinks can make individuals feel less drunk than they actually are.
"The consumption of high amounts of caffeine contained within energy drinks reduces drowsiness without diminishing the effects of alcohol resulting in a state of 'wide awake drunkenness,' keeping the individual awake longer with the opportunity to continue drinking," the authors of this latest review explain.
According to figures from the National Poison Data System in the US, 40% of the 4,854 calls made to poison information centers involving energy drinks also involved alcohol.
The team points to studies revealing that mixing energy drinks with alcohol increases smoking, illicit drug use, sexual risk taking, and engagement in other risky behavior - such as being taken advantage of or taking advantage of someone else sexually, or riding with an intoxicated driver.
The authors add:
"Research has continually shown the harmful risks associated with mixing energy drinks and alcohol; however, risks are still present when consuming energy drinks by themselves."
What should be done to reduce the harmful effects of energy drink consumption?
The authors suggest a number of strategies that they say policy makers should consider in order to reduce the occurrence of adverse effects of energy drink consumption.
Firstly, they state that a maximum limit should be set for the amount of caffeine allowed in one serving of an energy drink. "While the majority of energy drinks that control the market do not contain excessive amounts of caffeine, there are an increasing number of energy drinks entering the market that have caffeine concentrations well above those of mainstream energy drinks," they note.
Due to the potentially harmful effects of caffeine in children, the researchers say regulations should be introduced to stop children and adolescents being able to purchase energy drinks.
Health care providers should be fully aware of the dangers of excess caffeine consumption, the authors say, and these dangers should be discussed with at-risk individuals.
They also point to the current "aggressive marketing" of energy drinks toward children, adolescents and young adults, and believe regulators should take action. "Regulatory agencies should enforce industry-wide standards for responsible marketing of energy drinks and ensure that the risks associated with energy drink consumption are well known," they add.
Finally, the researchers say that further research is warranted to gain a better understanding of the potential adverse effects caused by energy drink consumption.
In conclusion to their review, the researchers say:
"As energy drink sales are rarely regulated by age, like alcohol and tobacco, and there is a proven negative effect of caffeine on children, there is the potential for a significant public health problem in future.
To date, policy development has been limited. Where policies exist, they are yet to be systematically evaluated in terms of their impact on heavy energy drink consumption, particularly among children and young adults. From a cautionary viewpoint, further research and policy action is necessary to minimize the risk of harm from heavy and long-term energy drink consumption."
Earlier this year, MNT reported on a study claiming perceptions that energy drinks are safe are caused by poor labeling and lack of education.