"Energy drinks" (EDs) often contain high levels of caffeine and sugar, with variable levels of taurine, guarana, other "supplements," and on occasion, vitamins. Frequently chosen by teens and young adults, the sale of EDs has enjoyed tremendous market growth. Over 4.6 billion cans of the most successful of these beverages, Red Bull, were sold in 2011. This prosperity resulted from the strong, recent worldwide annual growth, such as 11% in the United States, 35% in France, and 86% in Turkey.

Whether consumed alone or with alcohol or other drugs, EDs may have significant physical and behavioral effects (-). Marketing materials for EDs often imply that these products will improve energy level, attention span, and physical and/or mental performance . Red Bull has been shown to increase heart rate and blood pressure and can reduce cerebral blood flow; these effects can be potentiated under conditions of stress . EDs were responsible for over 20,000 emergency department visits in the United States in 2011, including a doubling in the incidence between 2007 and 2011.

In this issue of the Anatolian Journal of Cardiology, Elitok et al. reported on the electrocardiographic effects of Red Bull. They had particular interest in Red Bull's effects on ventricular repolarization. The dispersion of ventricular repolarization (DVR), as indicated by a longer interval between the T wave's peak and end (Tpe or Tpe/QT), correlates with arrhythmic risk in multiple populations .

The healthy volunteer medical students in this investigation consumed a single can of Red Bull under controlled conditions, and the effects on heart rate, blood pressure, and electrocardiographic measurements were observed. As expected, both blood pressure and heart rate increased following Red Bull consumption. However, no change in electrocardiographic DVR was found.

Should young club-going people take this news as vindication of their next order for a "vodka and Red Bull?" Can we write off Red Bull's cardiovascular effects as benign? Not so fast. The absence of an acute effect of a small dose of ED on one arrhythmia risk factor measured only in ECG lead V5 among a relatively small number of healthy young adults at rest does not equate to definite harmlessness. Our understanding of Red Bull's effects remains incomplete, especially in cases wherein larger doses are consumed, especially by sicker people and under more strenuous conditions.

Would the consumption of five cans of Red Bull affect healthy subjects' ECGs? Might only one serving of Red Bull affect ECG of a cardiomyopathy patient or ECG of a patient taking other cardiovascular active medications? Does chronic Red Bull consumption have the same or different effects as a Red Bull binge?

Elitok et al. should be congratulated for their interest in exposing potentially dangerous effects of popular EDs. More studies are required for us to declare Red Bull consumption to be harmless. For now, we can take heart in the absence of one signal of potential danger. At least this little bull is not in the proverbial china shop.

Energy drinks have the effects caffeine and sugar provide, but there is little or no evidence that the wide variety of other ingredients have any effect. Most of the effects of energy drinks on cognitive performance, such as increased attention and reaction speed, are primarily due to the presence of caffeine. Advertising for energy drinks usually features increased muscle strength and endurance, but there is little evidence to support this in the scientific literature.

A caffeine intake of 400 mg per day (for an adult) is considered as safe from the European Food Safety Authority (EFSA). Adverse effects associated with caffeine consumption in amounts greater than 400 mg include nervousness, irritability, sleeplessness, increased urination, abnormal heart rhythms (arrhythmia), and dyspepsia. Consumption also has been known to cause pupil dilation. Caffeine dosage is not required to be on the product label for food in the United States, unlike drugs, but most (although not all) place the caffeine content of their drinks on the label anyway, and some advocates are urging the FDA to change this practice.

Excessive consumption of energy drinks can have serious health effects resulting from high caffeine and sugar intakes, particularly in children, teens, and young adults. Excessive energy drink consumption may disrupt teens' sleep patterns and may be associated with increased risk-taking behavior. Excessive or repeated consumption of energy drinks can lead to cardiac problems, such as arrhythmias and heart attacks, and psychiatric conditions such as anxiety and phobias.

In Europe, energy drinks containing sugar and caffeine have been associated with the deaths of athletes. Reviews have noted that caffeine content was not the only factor, and that the cocktail of other ingredients in energy drinks made them more dangerous than drinks whose only stimulant was caffeine; the studies noted that more research and government regulation were needed

By: Todd M. Rosenthal and Daniel P. Morin

Source: A little Red Bull may give you wings, but it probably will not affect your Tpe

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