Energy drinks ‘have potential to harm the heart’
Drinking 4 cans of energy drinks causes changes to the body’s function that are more potentially serious than consuming just caffeine instead, according to a small study.
Researchers in the US found that drinking 32 fluid ounces – just under a litre – of a commercially available energy drink resulted in more profound changes to the heart’s electrical activity and blood pressure than drinking the same quantity of another drink containing the same amount of caffeine.
The study, in the Journal of the American Heart Association, says that both caffeine and energy drinks raised blood pressure, but that blood pressure returned to normal faster with the caffeine drink compared to the energy drink.
Sugar and caffeine
Energy drinks tend to be marketed towards younger people and are popular with students, motorists and those taking part in sport. The energy boost they provide comes from ingredients such as sugar, caffeine and taurine.
The study was initiated by Dr Emily Fletcher, deputy pharmacy flight commander from David Grant USAF Medical Center at Travis Air Force Base in California. She wanted to investigate the potential impact on heart health of energy drinks because of their popularity with air force staff and the fact that nearly 15% of military personnel, in general, drink 3 cans a day when they are deployed.
The researchers assigned 18 young volunteers into 2 groups. The first group were given 32 ounces of an energy drink that contained 108g (around 8-and-a-half tablespoons) of sugar and 320mg of caffeine, along with other ingredients. The second group was given the same amount of caffeine in a drink that also contained 40ml of lime juice and 140ml of cherry syrup in carbonated water.
After drinking these for 6 days, the groups swapped round.
ECG and blood pressure tests
The researchers measured the electrical activity of the volunteers’ hearts by electrocardiogram (ECG). They also took their blood pressure at the start of the study and at 5 other points during a 24-hour period.
They found that both the energy drink and caffeine-only groups had similar increases in systolic blood pressure – a measurement of the pressure of blood in arteries when the heart pumps. However, this had almost returned to normal in the caffeine-only group after 6 hours had elapsed.
In contrast, those who had consumed the energy drinks continued to have mildly elevated blood pressure.
The authors say this suggests ingredients in the energy drinks other than caffeine may have some blood pressure altering effects.
However, they say this needs further investigation.
Lack of scientific justification
In an emailed comment, Gavin Partington, director of the British Soft Drinks Association, says: “Caffeine in energy drinks is no different to caffeine in coffee so these findings are somewhat odd.
“The European Food Safety Authority latest opinion confirms the safety of energy drinks and their ingredients and therefore does not provide any scientific justification to treat energy drinks any differently to the main contributors to daily caffeine intake including tea, coffee and chocolate.
“It’s also worth remembering that coffees from popular high street chains contain the same or more caffeine than most energy drinks.”