Nutrient Bioavailability in Humans and Experimental Animals¹

Nutrient bioavailability is a highly recognized concept to which great importance is attached, yet which lacks clear definition. Ambiguities in terms and methodologies used to determine bioavailability have contributed greatly to the lack of clear definition. An attempt has been made in this article to clarify some of the terminology associated with the concept of bioavailability. Factors that affect bioavailability have been discussed in terms of environmental, organic and physiological occurrences. The effect of these factors is related to nutrient metabolism. Also, the relationship of the multitude of methodologies used to study nutrient bioavailability with the hierarchy of terms used to describe it is established. Finally, the care that is needed in the interpretation of bioavailability research, which is critical to the understanding of implications derived from this concept, is emphasized through specific examples.