Energy Drinks Linked to Heart & Blood Pressure Changes, While Caffeinated Drinks Shown to be Safer

27 Apr 2017 --- A new study has shown how the ingredients in commercially available energy drinks could be detrimental to heart health. Research showed how drinking 32 ounces of a commercially available energy drink resulted in more profound changes in the heart’s electrical activity and blood pressure. However, these symptoms were less apparent when subjects drank 32 ounces of a control drink with the same amount of caffeine.

The new research was shown in the Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association.

While the US Food and Drug Administration generally considers caffeine in doses of less than 400 mg as safe, energy drinks often consist of not only caffeine but proprietary energy blends.

With more than 500 types of energy drinks on the market, there has been an increase in energy-drink-associated emergency room visits and deaths, prompting questions about their safety, researchers said.

“We decided to study energy drinks’ potential heart health impact because previous research has shown 75 percent of the base’s military personnel have consumed an energy drink,” said Emily A. Fletcher, Pharm.D., study author and deputy pharmacy flight commander from David Grant U.S.A.F. Medical Center at Travis Air Force Base in California.

“And nearly 15 percent of military personnel, in general, drink three cans a day when deployed, which is more than we studied here.”

The study saw eighteen young participants randomly divided into two groups. The first group received 32 ounces of a commercially available energy drink (containing 108 g of sugar, 320 mg of caffeine, and various other compounds), while the second group was given a control drink containing 320 mg of caffeine, 40 ml of lime juice and 140 ml of cherry syrup in carbonated water.

After a six-day washout period, participants switched drinks. Researchers measured the electrical activity of the volunteers’ hearts by electrocardiogram. They also measured their peripheral and central blood pressures at the study’s start and at one, two, four, six and 24 hours after drink consumption.

Peripheral blood pressure is the measurement of the pressure in an outlying artery, typically an upper arm,” said Fletcher.

“Central blood pressure is the measurement of the pressure in the aorta near the heart,” she said.

“Blood pressures at each location are not always affected equally when a substance is introduced, such as medications.”

She explained, “Central blood pressure is an emerging and potentially superior method to assess health outcomes related to elevated blood pressure.”

They found that, when compared to the caffeine group, those in the energy drink group had a corrected QT interval 10-milliseconds higher at 2 hours.

“The QT interval is the measurement of the time it takes ventricles in the heart (the lower chambers) to repolarize, or prepare to generate a beat again. It’s the pause from the end of the electrical impulse generating the heart to beat to the next impulse,” Fletcher said.

“If this time interval, which is measured in milliseconds, is either too short or too long, it can cause the heart to beat abnormally.”

“The resulting arrhythmia can be life threatening.”

To put the 10-millisecond difference in perspective, there are medications that affect the corrected QT interval by 6 milliseconds and have warnings about the effect on product labels, Fletcher said. While both the energy drink and caffeine-only groups had similar increases in systolic blood pressure, systolic pressures in the caffeine group had almost returned to their original readings after six hours.

“On the other hand, those who consumed the energy drinks still had a mildly elevated blood pressure after six hours,” Fletcher said. “This suggests that ingredients other than caffeine may have some blood pressure altering effects, but this needs further evaluation.”

A spokesperson from the FDA told NutritionInsight, “The FDA does not typically comment on specific studies, but evaluates them as part of the body of evidence to further our understanding about a particular issue and assist in our mission to protect public health.”

“Because individuals may respond to caffeine differently, the FDA advises consumers who are concerned about the health effects of caffeine to consult with their health care providers.”

“We continue to caution consumers that products marketed as “energy shots” or “energy drinks” are not alternatives to rest or sleep. It is important for consumers to realize that, while stimulants such as caffeine may make one feel more alert and awake, judgment and reaction time can still be impaired by insufficient rest or sleep.”

“If you are thinking about taking one of these products, please consult your health care provider to ensure that you don’t have an underlying or undiagnosed medical condition that could worsen as a result of using them.”

Fletcher stated that based on this preliminary evidence in young, healthy adults, people who have high blood pressure, underlying cardiac conditions or other health issues might want to avoid or use caution when consuming energy drinks until more is known about their impact on heart health.

“This is a small study and further studies are needed to confirm these results,” she said.