Horse Racing: Is Cobalt Supplementation Beneficial or Harmful?

The use of cobalt in racehorses appears to be spreading. This trace element is believed to enhance the performance of horses given the supplement. However, its effects—whether positive or negative—are currently poorly understood.   Since last year, horse racing officials around the world have been taking an interest in a seemingly harmless substance: cobalt. This trace element, which is a component of vitamin B12 (cobalamin), is essential for the proper functioning of the body, in both humans and equines. But for some owners, cobalt supplementation gives their horses an edge over their competitors. And the practice is becoming widespread at racecourses. Until recently, researchers had not evaluated the beneficial or harmful effects of cobalt supplementation in horses. However, since this practice has drawn the attention of racing authorities, research on the subject has seen a resurgence of interest. Thus, in 2014, Heather Knych (University of California, Davis) and her colleagues conducted a study to evaluate how cobalt is distributed and acts within horses’ bodies following an intravenous injection of a single dose comparable to that used on the racetrack. They obtained several key findings:

• serum cobalt levels are very low, at less than 1 ppb (parts per billion);
• maximum serum concentrations following cobalt administration are extremely high;
• the substance’s half-life is approximately six and a half days, allowing for the conduct of anti-doping tests;
• serum concentrations ten days after administration remain high, between 20 and 50 ppb, which also allows for testing;
• no effects on erythropoietin levels or red blood cell counts in the blood have been reported, nor have any adverse effects at the injected dose.

Also in 2014, Emmie Ho (Hong Kong Jockey Club Racing Laboratory , China) and her colleagues worked on developing detection thresholds for cobalt. The research team proposed a threshold of 2 ppb on race day and 10 ppb for out-of-competition testing. Several additional studies are underway, notably to evaluate the adverse effects of cobalt, the consequences of administering cobalt-containing supplements, various detection methods, and more. In the meantime, the “illegal” use of cobalt is on the rise, even though its effects—both negative and positive—remain poorly understood. No one has yet scientifically documented its benefits in horses. In humans, doctors have used cobalt for decades to treat anemia. However, due to its numerous adverse effects (gastrointestinal, neurological, cardiovascular, and thyroid disorders), it was eventually phased out. Only certain athletes continue to use it... as a performance-enhancing drug.