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Energy drinks may increase BP, prolong QT interval
Energy drinks appear to increase BP and disturb the QT interval, researchers reported at the American Heart Association’s Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism Scientific Sessions.
Researchers studied data from seven previously published observational and interventional studies to analyze the effect of energy drinks on CV health.
The first part of the meta-analysis focused on the QT interval of 93 people who had just consumed one to three cans of energy drinks. The researchers found that the QT interval was 10 milliseconds (msec) longer after consumption of energy drinks, compared with baseline.
“The finding that energy drinks could prolong the QT [interval], in light of reports of sudden cardiac death, warrants further investigation,” Ian Riddock, MD, director of preventive cardiology at David Grant Medical Center, Travis Air Force Base, Calif., stated in a press release.
In the second part of the pooled analysis, which focused on systolic BP of 132 participants, energy drink consumption increased systolic BP by a mean of 3.5 mm Hg.
“The correlation between energy drinks and increased systolic BP is convincing and concerning, and more studies are needed to assess the impact on the heart rhythm,” Sachin A. Shah, PharmD, assistant professor at University of the Pacific, Stockton, Calif., said in the release.
The pooled studies included healthy patients aged 18 to 45 years.
For more information:
Shah SA. Abstract #P324. Presented at: American Heart Association Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism Scientific Sessions; March 19-22, 2013; New Orleans.
Disclosure: Riddock and Shah report no relevant financial disclosures.
Perspective
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The report by Shah et al raises the intriguing possibility that so-called energy drinks can raise systolic BP by about 3.5 mm Hg. There is much we don’t know about this effect. First, it is not clear which substances in the array of available drink products are thought to be responsible and by which mechanisms they might raise systolic BP. Another key question is related to the temporal characteristics of this effect. Does it occur immediately or within minutes of ingestion, or is the change in BP more gradual? Also, what is the duration of the increase? Does the BP remain elevated for minutes or hours or even days? And, most critically, does regular consumption of these drinks over a period of months or longer cause a permanent change in the BP even if use of these products is discontinued?
Should the increase in BP be only temporary, the implications might be rather modest. After all, if the intended use of these beverages is as energy replenishment for people who undertake physical exercise, a short-term increase of 3.5 mm Hg in systolic BP is only a small fraction of the far greater increase in BP produced by a typical aerobic workout.
The findings by Shah and colleagues should be considered as ‘hypothesis generating.’ Conclusions based on meta-analyses are often regarded as speculative, particularly when they depend on just seven studies selected out of a total of 351. Moreover, the findings of this report are based on a total of only 132 patients. More to the point, there is not a control group for this observation, again a reason to be cautious in interpreting the results. If there is a strong reason to be suspicious about the BP safety of energy drinks it should not be difficult, or even particularly costly, to design and conduct a straightforward randomized controlled trial to more definitively resolve the issue.
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Small changes in QT are difficult to quantitate and so this report needs to be taken cautiously. There are many details about the measurement that are not offered, but are crucial for proper interpretation of the data.
Nevertheless, given the multiple ingredients in unknown concentrations, it is not inconceivable that the effect is real and might be a part of the explanation of the harm that has been described. These findings point out, once again, the need for strict regulation of all supplements, even those considered to be innocuous by large segments of our population.