There is currently much debate over whether the use of organic minerals (minerals that are chemically attached to an organic compound like a small sugar or protein) are more bio-available than inorganic minerals. There are some largely unproven claims made about how much more bio-available the organic minerals are, and perhaps worse still, claims are being made that inorganic minerals are not able to be absorbed at all.

A study published in the 2011 proceedings of the Eqine Science Society Symposium (Dundon et al.) found that there was no difference on daily calcium balance or apparent calcium digestibility between calcium carbonate (limestone, an inorganic source of calcium) and calcium proteinate in exercised two and three year old geldings. This study is in agreement with Highfill et al (2005) but disagrees with results shown by Baker et al (2007).

The study by Dundon et al. did have a flaw in its design whereby horses on the calcium carbonate diet received more calcium than horses on the diet that substituted 40% of the calcium carbonate for calcium proteinate. This design flaw is acknowledged by the authors as making it difficult to interpret the data between diets.

There are certainly some studies that do show an improved bio-availability from some organic minerals, but there are many claims being made without good scientific evidence to support them. If you are considering paying a premium for a mineral supplement because it is organic, ask the manufacturer for the research that supports the product and their claims for superior bioavailability.