Was milk the reason for Toon Aerts and Shari Bossuyt's positive doping test? Rider's management warns cyclocross riders against consuming dairy products in Flamanville

On the 19th of January 2022 Toon Aerts tested positive in an out-of-competition test for Letrozole. Three days previous he raced the Flamanville World Cup - the last race where his result was not removed - and his management warns riders against what could've been a source of the substance.

This comes as Shari Bossuyt, female rider of Canyon//SRAM Racing, tested positive for Letrozole as well on the 19th of March this year during the Tour de Normandie, exactly 1 day after the race had finished in the town of Flamanville. The similarity between the two cases was astonishing and Toon Aert's management believes that something in the area is what led to the ingestion of Letrozole. They believe that dairy products could've been the source.

The agency, which manages other riders in the field, advised them not to consume dairy products in Flamanville and to bring their own food for the weekend trip into the French city. “That is why we have personally advised all our riders who will ride in Flamanville on Sunday to consume as little dairy products (such as yogurt and milk) from the region as possible. We also advised them to bring all their food with them from Belgium.”

“We still base this on our hypothesis that Toon and Shari tested positive after consuming dairy products in Flamanville. Their files show too many similarities to neglect that. Letrozole metabolite may be present in cow's milk. Our hypothesis is that their positive test is due to this, but this has not been confirmed by laboratory analyses."