Chocolate Treats Can Land Racehorse Trainers In Trouble

Researchers at Ohio State University found that three horses fed a vending-pack of M&M’s® chocolate-coated peanuts every day for eight days showed detectable concentrations of the stimulants caffeine and theobromine -- substances that are banned for horses that compete in races.

“We would advise that trainers avoid feeding chocolate to racehorses,” said Richard Sams, professor of veterinary medicine at Ohio State.

Caffeine and theobromine are banned for racehorses because they have been thought to give horses a competitive edge in races. Trainers whose horses test positive for these substances can lose their winnings and have their horse disqualified.

However, Sams said he doubts the amounts of caffeine and theobromine found in the horses he tested would have given theanimals a real advantage over other horses.

Sams began the research, which was published recently in the Journal of Analytical Toxicology, after a Florida racehorse trainer sent a horse’s urine sample to Ohio State for testing when another lab found caffeine in the sample. Sams said the trainer questioned if the M&M’s® he fed the horse caused the positive findings.

The chocolate in a vending machine bag of peanut M&M’s® contains six milligrams of caffeine and about 50 milligrams of theobromine. Both substances stay in a horse’s system longer than a human’s.

“This study helped us learn the way horses eliminate drugs, and by extension the way all animals eliminate drugs,” Sams said.

While caffeine is a central nervous system stimulant in horses, as it is in humans, it would take several grams of caffeine to affect the performance of a 1,000-pound racehorse, according to Sams.

Sams and Timothy Dyke, a senior researcher in veterinary medicine, fed three mares each 20 peanut M&M’s® -- the average amount found in a vending-machine pack -- on a daily basis. This allowed the researchers to determine accurate concentrations of both caffeine and theobromine in the horses.

Urine samples taken five to six hours after eating M&M’s® on the eighth day of feeding showed caffeine concentrations around 0.05 parts per million and theobromine concentrations at about 9.5 parts per million, enough to show up using current testing methods and enough to disqualify a horse.

“Caffeine and theobromine in these concentrations probably do not physically affect horses,” Sams said. Four days later, any trace of caffeine was undetectable while theobromine concentrations were extremely low -- about 0.75 parts per million.

The Association of Racing Commissioners International (ARCI), the association for many regulatory agencies for horse racing in the United States, classifies caffeine as one of the drugs that has the greatest likelihood of affecting performance.

“Virtually every drug is prohibited under the rules,” Sams said. “The ARCI drug classification system gives officials who generally have little knowledge of pharmacology some guidance as to what kind of penalties to impose.

“Yet racing regulators are beginning to realize horse racing is not well-served by issuing positive reports for drugs that are present in concentrations that can’t reasonably be expected to affect performance in any way,” he added.

While officials are gaining knowledge about drug concentrations and becoming more comfortable with making decisions about penalties, the rule remains that any foreign substance in a sample collected from a horse is a violation.

“Although the Florida trainer was eventually exonerated, he may have spent a few thousand dollars on testing,” Sams said. “There’s no guarantee that another racing commission won’t penalize someone for the same kind of infraction.”

This study was funded by the Ohio State Racing Commission and a private individual.