Athletes taking 'natural' supplements to give them a competitive edge were today warned abusing them could be harmful.
The European Society of Cardiology said an increasing number of sportspeople are using untested products — containing substances such as caffeine and creatine — to boost performance.
Despite being legal, nutritional products are often not subject to the rigorous safety standards of medications.
Writing in the European Journal of Preventive Cardiology, the ESC warned such products could pose 'a serious health risk' on their own, or when mixed with other substances.
Even caffeine, in high doses, can lead to a fast heart rate, heart rhythm disorders, high blood pressure and sudden cardiac death, it said.
Taking a cocktail of substances can be 'extremely dangerous' because they could interact, the ESC also said.
And because they are not rigorously regulated, they could also be contaminated with illegal chemicals that violate doping rules.
The ESC wants athletes to use products from 'well-established manufacturers with known and internationally approved good quality standards'.
At least four in 10 sportspeople take legal supplements, such as energy drinks, over-the-counter and prescribed medicines and experimental drugs, to gain a competitive edge. But the European Society of Cardiology (ESC) warned these supplements, including plant-based and natural extracts such as caffeine, could pose 'a serious health risk' and break anti-doping rule
The World Anti-Doping Agency (WADA) prohibits performance-enhancing drugs — but does not include nutritional substances.
But an investigation by the UK's drug watchdog previously found tens of energy and 'muscle-gain' sports supplements contained steroids, stimulants and hormones.
The ESC said: 'Athletes who use supplements often have no knowledge regarding their effects on sports performance and overall health.
