The Trace element Cobalt – the latest doping scandal?
This week saw a guilty verdict in a long-running case over cobalt doping against Australian trainers Lee and Shannon Hope brought by Racing Victoria. But what is cobalt and why the interest?
Scan the list of ingredients on a vitamin and mineral supplement and you may occasionally come across cobalt. Many horses owners may not even have heard of cobalt and even fewer will not be aware of what it does but that could all be about to change. Pure cobalt is a hard, dense silver-white metal although in nature cobalt only exists in combination with other compounds. In fact most of the planet is in the Earth’s core. Cobalt is a micro-mineral or trace element and is only required in the horses’ diet in very small amounts. Cobalt is an essential part of Vitamin B12 which is also known as cobalamin. Vitamin B12 has many essential functions including formation of red blood cells, nervous system function, DNA synthesis and fat and amino acid metabolism. Almost half the cobalt in the horses’ body is stored in muscle and bone. Vitamin B12 is not synthesised by the horse itself but by bacteria in the hindgut. However cobalt can also be toxic and this is the reason why many suppliers and manufacturers refuse to handle cobalt or include it in supplements. Under EU law cobalt cannot be included at more than 2mg per kg in feed products. High intake of cobalt in people causes vomiting, vision problems, heart and thyroid damage, lung disease and is suspected of being carcinogenic (causing Cancer). Given the toxicity of cobalt and the fact that supplementing horses with Vitamin B12 eliminates the dietary requirement for cobalt, many feed and supplement manufacturers have stopped using cobalt compounds entirely and this is why cobalt may not appear on many supplement labels in Europe. A common form of Vitamin B12 that you may see on feed or supplement labels is cyanocobalamin.
So why is cobalt in the news? One of the most interesting effects of cobalt, especially if you are training racehorses or endurance horses, is that cobalt has a similar action to the hormone EPO (erythropoietin); it causes the body to produce more red blood cells. This in turn leads to an increased capacity to carry oxygen and results in increased performance in both high-intensity and endurance events. Of course, this is considered by racing bodies and the FEI to constitute doping. There has been suspicion that cobalt was being used as a doping agent several years ago but it wasn’t until more recently that regulatory authorities started to monitor cobalt levels in race horses. In Australia thresholds of 200ug (0.2mg) per litre of urine were set by several racing authorities and earlier this year three Australian trainers were under investigation for horses testing positive for cobalt above the threshold level, with the implication being that these horses had been fed abnormally high levels of cobalt, presumably to increase red blood cell numbers and improve performance. Other positives for cobalt occurred in many other racing jurisdictions, including in the US. Racing seems to have the cobalt problem under control, at least as far as cobalt use near or on raceday is concerned. Of course as red blood cells live for several months, it’s possible that cobalt could be used to stimulate red blood production and then its use stopped to allow levels in urine to return to below the threshold before racing. However, perhaps fortunately for regulators, cobalt is cleared relatively slowly from the body. For example, following a single dose, cobalt levels in plasma are still elevated 10 days later.
Interestingly, cobalt is not yet on listed on the FEI Prohibited Substances database.
For further reading: Cobalt chloride doping in racehorses: Concerns over a potentially lethal practice. (2015) Ali Mobasheri and Christopher J. Proudman. The Veterinary Journal, Volume 205, Issue 3, September 2015, Pages 335–338. http://www.sciencedirect.com/science/article/pii/S1090023315001471