Bioavailability of Minerals
It is well known that the concentration of a nutrient in a food is not a reliable indicator of its nutritional value. In other words, the entire quantity of the nutrient present in the food may not be utilized by the human body.
Bioavailability may be defined as the proportion of a nutrient in the ingested food that is available for utilization in metabolic processes. In the case of mineral nutrients, bioavailability is determined primarily by the efficiency of absorption from the intestinal lumen into the blood.
In some cases, the absorbed nutrient may be in a form that cannot be utilized. Bioavailability of mineral nutrients may vary from less than 1% for some forms of iron to greater than 90% for sodium and potassium. Chemical form of the mineral in food, formulation of chelates with minerals, redox activity of food components, mineral - mineral interactions and physiological state of the consumer are the factors that may influence the mineral bioavailability from foods.