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Time To Dampen the Enthusiasm For Energy Drinks

“Energy drinks” like Red Bull and Monster can provide pep but are not without risk.

Yes, Max Verstappen, world champion Formula 1 driver, does drink Red Bull. How could he not? After all, he drives for the Red Bull racing team! Max has said that he may drink as many as six cans of the energy drink during a race weekend, although he has not revealed whether he indulges just before a race for extra alertness. However, there are many athletes in various sports who do rely on energy drinks for a boost. They, though, are not the marketers’ prime target. Advertising is mostly directed at young adults who seek a vibrant and energetic lifestyle and identify with the world-class athletes and teams sponsored by energy drink companies. Can these young adults be getting something more than what they bargained for? Like an increased risk of sudden cardiac arrest? That’s what some studies suggest.  

As with so many other lifestyle interventions, consuming energy drinks comes down to a risk-benefit analysis. In nutrition, the term “energy” generally refers to the calorie content of a food or beverage. Not so in the case of “energy drinks.” These beverages are designed to provide mental and physical stimulation beyond their calorie content, mostly due to the large amounts of caffeine, anywhere from 80 to 300 mgs, that they contain. Often, guarana which is another caffeine source is added along with other substances of questionable significance such as taurine, glucuronolactone, B vitamins, carnitine, inositol, yerba mate, Kola nut, milk thistle, Ginkgo biloba and ginseng. There is usually a huge dose of sugar, although varieties with artificial sweeteners are also available. There is no question that the main “energizing” component is caffeine, roughly as much as in two cups of coffee.

Do these drinks really deliver on the promise of increased mental and physical energy? As is often the case in nutritional research, there is no clear-cut answer. Some studies show a benefit, others do not. The most frequently cited positive study takes us back to 2001 when researchers at the University of West of England subjected 36 university students to tests that measure mental concentration, reaction time, memory, physical endurance and performance. There was modest improvement in all categories after drinking 250 mL of Red Bull as compared with a flavoured, carbonated water beverage that served as control. Other studies documented improved performance in cyclists and better reaction time in a group of tired volunteers in a driving simulator. On the other hand, female student volunteers at the University of Dammam in Saudi Arabia showed no improvement in any parameter on a standard treadmill test after drinking an energy beverage. Neither was there any improvement seen in elite volleyball players in Costa Rica who were subjected to various performance tests. Overall, the evidence for consuming energy drinks for improved mental or physical performance is less than compelling.

Now for the downside. Energy drinks can increase heart rate and blood pressure, normally not a problem for most people, but can present a risk for individuals with undiagnosed heart conditions. The effect on the heart appears to be greater than that due to caffeine alone, meaning that other components like taurine and glucuronolactone may be making a contribution. In 2013, McGill University Health Center physicians surveyed the published literature dating back to 1980 for cases in which heart attacks, serious arrythmias, and sudden cardiac deaths were linked with energy drink consumption. They found 17 cases, admittedly a very small number in comparison with the number of energy drink consumers, but nevertheless concerning since only in one case was there evidence of a previous minor cardiac problem. In most cases consumption was heavy, meaning about three cans in a short period prior to the event. In three of the cases the energy drink was consumed with vodka, a combination that increases risk.

A recent study at the famed Mayo Clinic in Minnesota corroborates these findings. Doctors reviewed the medical records of 144 survivors of sudden cardiac arrest that were triggered by arrythmias and discovered that 7 had consumed an energy drink prior to the event. Genetic testing revealed that 5 of the victims had an undiagnosed medical condition that made them more prone to irregular heartbeats. Although once again, relative to the total number of the 144 sudden cardiac arrests, the ones linked to energy drinks (5%) were few, they are statistically significant.

Adding further to the concerns, a 2019 paper in the Journal of the American Heart Association reported on the cardiac effects of drinking 950 mL (two large cans) of either of two different energy drinks by 34 healthy young volunteers. Electrocardiograms were taken and blood pressure was monitored. An abnormally long time taken by the heart’s chambers to relax after contracting, known as the QT interval, was noted. Such prolonged times are associated with an increased risk of abnormal heart rhythms and sudden cardiac death. The subjects’ blood pressure was also found to increase, which was not unexpected for such a high dose of caffeine. While the overall number of cases in all these studies is small, the consistency of the results is enough to raise concerns about the consumption of energy drinks, especially given that a significant percentage of the population is known to have undiagnosed genetic risk factors for heart disease.

To complicate matters even more, it is not only cardiac events that have been linked with the consumption of energy drinks. Researchers at Newcastle University in England reviewed 57 studies that covered 1.2 million children in 21 countries and determined that energy drink consumption was associated with poor sleep quality, lower academic performance, anxiety, depression and increased risk of attention deficit hyperactivity disorder (ADHD). Frequent consumers of energy drinks were also more likely to experiment with alcohol and smoking. As a result, many countries have banned the sale of energy drinks to anyone under age 18.

Where does all this leave us? As with most nutritional issues, somewhat confused. We could certainly live quite nicely without energy drinks, but they are not going away. There is just too much money involved. We are looking at a multi-billion-dollar industry! For the vast majority of the population the risk is minimal, but how minimal is an open question since victims of cardiac events are not always questioned about what they may have been consuming. Then there is the issue of the demonstrated increased risk for individuals who have a genetic disposition to arrythmias, a condition of which many may be unaware. Also, the cardiac effects of ingredients other than caffeine in energy drinks needs further exploration. At the very least, there should be a requirement to list the exact amounts of all ingredients on the label. The vigorous marketing that targets young adults with promises of boosting energy has certainly boosted sales. It is a good bet that it will also boost activity in emergency rooms.


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