Doctors in the UK are flagging concerns about high energy drink consumption after a healthy man in his 50s suffered a stroke while regularly drinking eight cans a day.
The case, published in the British Medical Journal, describes how the man was unaware of how much caffeine he was consuming.
After stopping the drinks, his blood pressure returned to normal, but he was left with reduced sensation down his left side.
Health professionals note that while the recommended daily caffeine limit is 400mg, some large energy drink cans contain as much as 500mg each — and the true amount may be higher once other ingredients are taken into account.
Researchers say the combination of caffeine, high sugar levels and other additives may amplify the drink’s effects, although they caution that it is difficult to prove a direct cause of the stroke.
They are calling for further research into how these products affect the body.
A spokesperson for the British Soft Drinks Association, which represents the industry, said that energy drink ingredients are considered safe by the European Food Safety Authority and that regulations already require clear labelling for products with high caffeine levels.
Energy drinks are promoted as products that boost alertness and performance, yet they often contain substantial amounts of caffeine, sugar and added stimulants such as taurine and guarana.
Growing use among teenagers has prompted concerns about short-term effects on the heart, sleep problems and digestive complaints.
Despite the fast global growth of the category, energy drinks still account for only a small portion of the EU’s non-alcoholic beverage market. EFSA’s consumption data show that adolescents are the most frequent consumers, and a share of them use these products heavily and on a long-term basis.
There is no EU-specific legislation covering energy drinks. The main requirement comes from Regulation (EU) 1169/2011, which obliges manufacturers to include a clear caffeine warning on products with high levels.
Industry groups such as UNESDA and Energy Drinks Europe follow their own voluntary rules, including restrictions on marketing to children.
National approaches differ widely. Lithuania, Latvia, Poland, Romania, Hungary and Bulgaria have all introduced age restrictions on sales, while other countries rely only on voluntary agreements with retailers.
EFSA opinion
The European Food Safety Authority carries out risk assessments for the EU’s food and agriculture sectors. In February 2013, following concerns from several Member States about possible health impacts of caffeine — including effects on the heart, sleep problems, anxiety and potential risks during pregnancy — EFSA was asked to produce a scientific evaluation.
The request also covered whether caffeine interacts with other common ingredients found in energy drinks.
EFSA released its assessment in May 2015. The authority reviewed available evidence on caffeine from all dietary sources and concluded that healthy adults are unlikely to face health risks from single doses of up to 200 mg, or about 3 mg per kilogram of body weight, even when taken within two hours of intense physical activity.
For regular use, daily intakes of up to 400 mg were deemed safe for the general adult population.
For pregnant and breastfeeding women, EFSA found that consuming up to 200 mg of caffeine per day does not pose a risk to the foetus or nursing infants.
For children and teenagers, EFSA applied body-weight-based limits. It was determined that the same level considered safe for adults — 3 mg per kilogram of body weight per day — can also be applied to younger age groups, as they metabolise caffeine at a similar rate. Research on short-term behavioural and anxiety-related effects in children and adolescents supports this threshold.
EFSA therefore proposed a safety limit of 3 mg per kilogram of body weight per day for regular caffeine intake in children and adolescents.
This content is for informational purposes only and should not be considered medical advice; individuals should consult a healthcare professional regarding caffeine consumption or any health concerns.
10.12.2025.
