In March 2019 researchers from Germany published the results of their study to assess the cardiovascular and metabolic effects of energy drinks, a control product without certain ingredients found in energy drinks (caffeine, taurine, or glucuronolactone), and a control product with the certain ingredients found in energy drinks. A total of 38 adults (19 men, 19 women, average age 22 years, average BMI 23 kg/m2) were involved in the study. Each individual was given two different amounts of each product on different occasions, namely 750 mls or 1000 mls. Results showed that the control product with and without the certain ingredients were tolerated with no dose-dependent effects on blood pressure, heart rate, QT interval (a measurement made on an electrocardiogram used to assess some of the electrical properties of the heart) and glucose metabolism. However, following consumption of the energy drink 11% of the individuals reported symptoms, which is in contrast to the 0-3% of individuals who reported symptoms following the two control products. Specifically, one hour following consumption of the energy drink an increase in systolic blood pressure as well as QT prolongation were seen. It was noted that caffeine, but not taurine or glucuronolactone, caused an increase in blood pressure but not QT prolongation. The effect on blood pressure was most pronounced after 1 hour and returned to normal after a few hours. A deterioration in insulin sensitivity was also seen 1 hour following consumption of the energy drink. The researchers therefore concluded that a single energy drink appears to cause an increase in blood pressure and QT interval as well as a deterioration in insulin sensitivity in young healthy adults, and that these effects could not be easily attributed to the single components of caffeine, taurine, or glucuronolactone.
Basrai M et al. Energy Drinks Induce Acute Cardiovascular and Metabolic Changes Pointing to Potential Risks for Young Adults: A Randomized Controlled Trial. J Nutr. 2019 Mar 1;149(3):441-450