Non-provitamin A activity of carotenoids: immunoenhancement

Abstract

Substantial evidence has accumulated in recent years that suggests new nutritional roles for certain carotenoids in addition to the value of some as a source of vitamin A. Unfortunately, the commonly used calculation of the carotenoid contents of foods as retinol equivalents does not take the non-provitamin A activities of carotenoids into account. Thus, there is a need to express the content of β-carotene and, perhaps, other carotenoids in foods in milligrams, and to establish a new and separate recommended dietary allowance (RDA) for such nutrients.