Total Body Vitamin A Pool Size in Preschool Children Before and After Vitamin A Supplementation in an Impoverished South African Community Where Liver is Frequently Eaten and Children Exposed to Vitamin A Fortified Staple Foods

Serum retinol, the most commonly used indicator to assess vitamin A status, is homeostatically controlled and, although it is able to detect deficiency, it does not necessarily reflect liver stores or measure excessive vitamin A intake. The stable isotope dilution method is able to measure total vitamin A body pool size over the vitamin A status continuum, including the sub-toxic range,and would add valuable information about the vitamin A status in a community where liver (an exceptionally rich source of vitamin A) is frequently eaten, and children also exposed to other vitamin A interventions. Total body vitamin A will be assessed before and 4 weeks after a high dose vitamin A supplement given to the children as part of the national vitamin A supplementation program. The confounding effect of infection/inflammation on the biomarkers of vitamin A status will also be examined, as well as how serum retinol and retinol binding protein relate to each other, and to vitamin A pool size.