LONDON (AP) — Tour de France champion Alberto Contador’s claim that bad meat is to blame for his positive doping test is entirely plausible since clenbuterol is commonly given to animals destined for human consumption, experts say.
The drug is often used to speed up growth in animals, including chickens, cows and pigs. Clenbuterol is usually stored in the liver or muscle tissue.
Contador has been provisionally suspended after the International Cycling Union said a “small concentration” of clenbuterol was found in his urine sample on July 21 during the Tour de France, which the Spanish rider won for a third time.
Contador blamed the finding on “food contamination,” saying he ate contaminated beef brought from Spain to France on a rest day.
Doctors said it would have been nearly impossible for Contador to have received any performance boost from eating clenbuterol-spiked meat.
“The amounts (of clenbuterol) would be incredibly small unless you were eating vast quantities of meat,” said Dr. Andrew Franklyn-Miller, a sports medicine expert at the Centre for Human Performance in London and a team doctor for Britain’s rowing team.
He said Tour de France cyclists typically try to have the leanest muscle mass possible. Because meat is harder to digest, most cyclists primarily eat carbohydrates like pasta, which is easier for the body to break down for energy than meat.
“It’s very unlikely that the night before a stage in the mountains, anyone would be eating three or four steaks,” Franklyn-Miller said.
Spain has reported several past outbreaks linked to clenbuterol after people ate contaminated beef and veal. In the 1990s, more than 100 people had symptoms including increased heart rate, muscle tremors, nausea, headaches, and anxiety.
Clenbuterol has been used for years by bodybuilders to increase their muscle mass and reduce fat. The drug also increases the body’s aerobic capacity by making more oxygen available for muscles to work. Clenbuterol is also thought to help the body burn more fat, giving athletes a longer energy supply. Its short-term effects are similar to amphetamine drugs.
In some countries, clenbuterol is used to treat breathing disorders like asthma by relaxing the muscles in the airways, but it is not approved for use in humans in the United States and most of Europe.
Contador is not the only athlete to blame contamination for a positive clenbuterol test. Last week, German table tennis player Dimitrij Ovtcharov used the same defense after testing positive for the drug, saying he ate contaminated meat during a tournament in China.
Athletes who use the drug for doping purposes can also suffer from side effects such as weight gain, loss of bone density and organ damage.
Animal studies have shown clenbuterol can increase muscle mass and body weight by accelerating muscle growth, but no studies in humans have proven the same effects.
Michael Audran, a doping expert who works closely with the World Anti-Doping Agency, said the amount of clenbuterol found in Contador’s samples was so small it is unlikely the cyclist was abusing the drug. He said the contamination theory is the only possible explanation for the positive result.
Other experts said the doping tests need to be refined to include a threshold amount for clenbuterol, not simply whether or not the drug is present.
“The quantity is the key to judging whether it was a case of possible doping or contaminated meat,” said Giuseppe Banfi, a sports biochemistry expert at the University of Milan. “We don’t have the proper parameters right now to know if this was illicit use.”
He said that if Contador was doping with clenbuterol, authorities likely would have found more than one positive test result to show systemic drug abuse.
“WADA needs to set a detection limit (for clenbuterol), that is fundamental to defining if it is illicit use or an accidental finding,” Banfi said.
Clenbuterol remains in the body for more than a day after it is ingested. The drug can be detected via hair and urine analysis.
AP Sports Writer Samuel Petrequin in Paris contributed to this report.