Downing several strong energy drinks every day may pose a serious stroke risk, doctors have warned in the journal BMJ Case Reports, after treating an otherwise fit and healthy man in his 50s with a daily 8-can habit and exceedingly high blood pressure.
The findings prompt the authors to call for tighter regulation of the sales and advertising of these drinks, particularly given their popularity among young people.
The man in question had a stroke in his thalamus—the part of the brain involved in sensory perception and movement. His symptoms included left-sided weakness, numbness, as well as difficulties with balance, walking, swallowing and speech—collectively known as ataxia.
On admission to hospital his blood pressure was 254/150 mm Hg, which is regarded as extremely high.
He was started on drugs to lower his blood pressure, and his systolic blood pressure—reflecting arterial pressure during the heart's pump action—fell to 170 mm Hg.
But once back home, his blood pressure rose again and remained persistently high despite the ramping up of his drug treatment.
On further questioning, he revealed that he drank an average of 8 energy drinks every day, each of which contained 160 mg of caffeine, adding up to a daily intake of 1200-1300 mg of caffeine: the recommended maximum daily intake is 400 mg.
He was asked to give up this daily habit, after which his blood pressure returned to normal and blood pressure lowering drugs were no longer needed.
But he didn't regain full feeling on his left side. Commenting on the experience, he said: "I obviously wasn't aware of the dangers drinking energy drinks were causing to myself. (I) have been left with numbness (in my) left hand side hand and fingers, foot and toes even after 8 years."
The report authors point out that the man's lack of awareness about the potential cardiovascular risks associated with heavy energy drink consumption is probably not surprising as they aren't generally thought of as a potential cardiovascular disease risk.
"The year 2018 saw major UK supermarkets implement a voluntary ban on sales of [these drinks] to under 16s in a drive to tackle obesity, diabetes, and tooth decay, but less explored are the possible increased risks of [energy drinks] for cardiovascular disease, including ischaemic [restricted blood supply or blood clot] and haemorrhagic [bleed in the brain] strokes, particularly in younger demographics otherwise expected to have lower stroke risk," they emphasise.
Energy drinks contain more than 150 mg of caffeine per litre and typically have a very high glucose-based sugar content and varying quantities of other chemicals, they highlight.
"This declared amount is the 'pure caffeine', but other ingredients contain 'hidden caffeine'— for example, guarana is thought to contain caffeine at twice the concentration of a coffee bean.
"The hypothesis is that the interaction of these other ingredients, including taurine, guarana, ginseng and glucuronolactone, potentiates the effects of caffeine heightening stroke [cardiovascular disease] risk through numerous mechanisms," they explain.
"The average [energy drink] is said to contain around 80 mg of caffeine per 250 ml serving, compared with 30 mg in tea and 90 mg in coffee, but in some cases can contain up to 500 mg in a single serving," they point out.
This report represents just one case, but the authors nevertheless conclude: "While the current evidence is not conclusive, given the accumulating literature, the high morbidity and mortality associated with stroke and [cardiovascular disease] and the well-documented adverse health effects of high-sugar drinks, we propose that increased regulation of [energy drink] sales and advertising campaigns (which are often targeted at younger ages) could be beneficial to the future cerebrovascular and cardiovascular health of our society."
