Question

I recently won a free horse-hair mineral analysis in a raffle. The most surprising result was a toxic level of cadmium. My 11-year-old gelding has none of the expected clinical signs and lives in a remote area, far from any pollutants. I have no idea as to the origin of the exposure, except perhaps his forage. A representative of the company that did the analysis explained that cadmium can cross in the placenta to the foal and that may be my horse’s source of exposure, but I doubt this, given his age. I have worked out my horse’s diet with the help of a nutritionist, so I was quite surprised by some of results. As a scientist, I question the results, as well as the validity of the science behind the analysis, but I have an open mind. What are your thoughts?

Answer

I understand your concern. While there are numerous claims that dietary imbalance, metabolic disease, and many other health problems can be diagnosed by interpretation of hair analysis, individual variation among horses makes it not as accurate or user-friendly as we would like. However, hair analysis is known to be reasonably reliable for detecting exposure to heavy metals.

From my understanding, cadmium contamination in hair is not totally dependent on dietary intake of cadmium, and there is a tremendous amount of individual susceptibility to the deposition in hair. The most common source of cadmium exposure in humans is through smoking. Why your horse tested so high in cadmium is mysterious, since there is no obvious exposure, but it may come down to the individual vulnerability to accumulating the heavy metal from the environment.

Although you didn’t mention the level of cadmium in your horse, in a presentation given by Dr. Manfred Coenen of values interpreted from 72 studies and communications, the mean hair cadmium levels for horses not exposed to heavy metals were 0.181 mg/kg DM, and those with differing levels of exposure were 0.96-3.47 mg/kg DM.

If your horse appears to be healthy in every way, I imagine that the cadmium may not be of a great concern since cadmium toxicity can have some detrimental effects on the body. You may want to look into a simple detox or chelation regimen as a precaution.