Factors DFetermining Bioavailability of trace Minerals
What is the quantity of metal which is effectively bound ?By simple calculation we can determine the maximum percentage of metal effectively bound to the organic ligand. It is found that smaller ligands (Lowe molecular weight ex. Glycine) will bind the maximum of metal while products with long chains (higher molecular weight) will have lesser binding percentage.
What is the stability of the compound before absorption ?The Staility constant is a value which expresses the tendency of a metal and ligand to bind together or the affinity between a metaln ion and a ligand (Nelson, 1988). Higher the value of stability constant, stronger is the ond between metal and ligand
Organic minerals with ligand as single amino acid or dipeptide have greater stability constant. If the ligand is a polypeptide with higher molecilar weight, the stability constant ususally decreases. The stability constant must be high enough to allow intact absorption of metal ligand complex and low enough to allow metal ion dissociaiton at metabolic point of use.
Will the compound be absorbed as such ?The enterocytes can absorb intact molecules up to a certain size. Low molecular weight ligand is normally absorbed intact. Larger molecules breaks down in the lumen setting the metal ion free, thereby losing the benefit of Chelation.