Over 3.5 billion cans of Red Bull are sold every year in over 120 countries, claiming the drink leads to “improved performance, concentration, vigilance and emotional status” (RedBull website).
Other energy drinks such as ‘V’, ‘Monster’ and ‘Mother’ are available on the Australian market, all of which contain variations of three main components, caffeine, taurine and glucuronolactone. These energy drinks are marketed to young adults between 15 and 30 years of age.
A recent consumer survey from the United States demonstrated that over 50 percent of young adults between 15 and 30 years old consume at least one energy drink per month, often mixed with alcohol. Moreover, excessive consumption of energy drinks, up to between seven and 12 cans a day, is not uncommon.
Harmful effects of energy drink consumption
Energy drink consumption has been linked to sudden cardiac death. However, determining the direct contribution of energy drinks to adverse outcomes has been difficult as these drinks are often consumed with other recreational drugs, such as alcohol.
Initial alarm was raised in 2001 following three cases in Sweden of otherwise fit and healthy subjects dying following ingestion of energy drinks. Numerous other reports exist in the media linking energy drink consumption to sudden deaths - two recent reports include a 40-year-old male clerk who died after ingesting four cans of energy drink and a 21-year-old female who collapsed and died after multiple cans of energy drink.
While two of these cases were associated with alcohol consumption, there was enough concern to lead to the banning of this product from regular sale in Norway and Denmark. In these countries, the product can only be sold in pharmacies and is classified as a medicine due to its high caffeine content.
Australian and New Zealand food authority - Food Standards Australia New Zealand - has not gone to such extremes. Such drinks are required to have a warning stating “This food contains caffeine and is not recommended for children, pregnant or lactating women and individuals sensitive to caffeine,” with a further suggestion for consumers to limit usage to two cans per day.
A link between energy drink consumption and heart attack
A recent report from Australia has linked energy drink consumption with heart attacks (Medical Journal of Australia, 2009). A healthy 28-year-old who was fit and not taking any regular medication suffered a heart attack following the consumption of seven or eight cans of energy drink over a seven-hour period. While this person was a smoker, this case suggested that the energy drink or its major component caffeine, contributed to the heart attack.
At present, there is limited scientific investigation into a direct link between energy drink consumption and cardiovascular or other adverse outcomes. Toxicity and adverse event registries should be established to monitor the potential dangers of energy drinks.
Energy drink consumption and heart disease risk
We have recently demonstrated that energy drink consumption is associated with increased cardiovascular risk (American Journal of Medicine 2010).
Fifty fit and healthy volunteers aged between 18 and 30 were tested before and one hour after the consumption of one can of a sugar-free energy drink. We demonstrated that consumption of an energy drink induced significant physiological changes such as increased blood pressure, increased stickiness of the blood (clot formation) and abnormal blood vessel function (blocked artery).
The above measures are all well-documented abnormalities in cardiovascular disease and/or its risk factors. This research suggests that fit and healthy individuals may be at increased, albeit small, risk of an adverse cardiovascular event following energy drink consumption.
This risk may be more pronounced in at-risk individuals, such as those with known or unknown structural heart disease, electrical abnormalities of the heart and those with high risk factors for coronary artery disease such as diabetics, people with high blood pressure and high cholesterol and smokers, or when consumed in combination with excessive exercise or alcohol.
While this research does not establish a direct link between energy drink consumption and adverse cardiovascular outcomes it clearly highlights the need for further investigation into the immediate and long-term health and clinical implications of these findings.
Given the prolific use of energy drinks within the young population, including among school-aged children, further research into the effects of energy drinks has the potential for widespread impact.