By Guy Dresser | Royal Canoe Club - International sporting federations are becoming increasingly worried about the number of athletes taking unapproved food supplements. Earlier this year a canoeist, Jan Sterba (pictured below), failed a doping test in the run-up to the London Games.

He blamed a nutritional supplement called “Shot Gun” for the doping violation. Although he subsequently competed in London after a prolonged legal battle, his case – and others in several sports – is seen as indicative of a rising trend of athletes who don’t seem to think through the consequences of taking unapproved supplements.

Soccer’s governing body FIFA yesterday said around 35% of players at World Cup level were regularly taking food supplements, with that figure rising to almost 50 percent at under-17 and under-20 level.

FIFA chief medical officer Jiri Dvorak said a failure to seek advice before taking something meant players incurred an increased risk of failing doping tests.

“The marketing strategies of the producers of food supplements are influencing the behaviour of footballers and athletes in general,” Dvorak said in an article on the FIFA website.

“From different surveys we know that about 60 percent of under-16 athletes in the US are using nutritional supplements daily and all of them believe they will increase their performance.

“This is definitely not based upon the scientific evidence or literature, which says the opposite,” he added.

Dvorak said he was both surprised and alarmed that athletes were not seeking specialist advice.

“It is well established and proven that many of the food supplements are contaminated by prohibited substances such as anabolic steroids and other substances.

FIFA has issued a serious warning to football players not to take any food supplements that have not been passed by national drug and food administrations.

Dope tests today are so sensitive that in some countries the chemicals ingested by cattle can see meat consumers fail tests for anabolic steroids. The most well-known example of this came at the 2011 Under 17 World Soccer Championship in Mexico where more than 100 players failed doping tests after the banned substance clenbuterol was detected – its presence was blamed on contaminated meat.

Read more about food supplements on the ICF website here.