The head of the Dutch anti-doping authority has raised his concerns over Jumbo-Visma and their use of the controversial Ketones supplement drink. Herman Ram told Dutch newspaper De Limburger that he was 'uncomfortable' with the team's use of the product and believes it exists in the 'grey area'.
Ingested as a soluble powder, ketones are a natural substance produced in the liver. The body uses them as an alternative energy source when it has run out of carbohydrates to burn, turning towards burning fat.
Synthetic ketones are claimed to be used as an extra energy source, acting as an alternative to carbohydrates while reducing lactic acid and helping to aid recovery.
Ketones are currently not banned by the World Anti-Doping Agency, being labelled as a dietary supplement, although their status has been considered previously. There has also been criticism from some corners that the long-term effects of the supplement are yet to be fully investigated.
Ram shares these concerns and admits that Jumbo-Visma's use of the supplement is something he would advise against.
'It is a legal nutrition but, at the same time, too little is known about the possible health consequences,' Ram said. 'That makes it a grey area. It is not on the doping list, but if we receive questions from athletes, we advise them not to use ketones. Team Sunweb does not use them for that reason, either. I find it uncomfortable that Jumbo-Visma does.'
Jumbo-Visma are regarded as the team set to challenge Team Ineos's eight-year reign at the Tour de France this July. Adding Tom Dumoulin to the fold over winter, they will ride with a triple leadership of Primoz Roglic, Steven Kruiswijk and Dumoulin at this year's race.
Cyclist interviewed Keiran Clarke, Professor of Physiological Biochemistry at Oxford University and inventor of the first ketone-based drink previously about the supplement's performance-enhancing benefits.
Clarke was sceptical about the possible benefits of the product for endurance athletes, calling it no superior to glucose and certainly dependant on the individual ingesting ketones.
'If you have glucose by itself or ketones by itself, it’s not superior. It’s exactly the same – it’s just providing energy. For sprints glucose is better actually because you need something that’s anaerobic,' said Clarke.
'Things that last five or six hours will probably be the best use for it. But I think it depends on the individual, and it also depends on how efficient they are at using their various substrates.’