Mathematical modeling predicts that six-monthly vitamin A supplementation from 6-59 months of age does not result in excessive total body vitamin A stores

Abstract Number Theme Presentation Type Cover Approved
0528 Risks or risk/ benefit of micronutrient interventions Poster Not Approved


Abstract Content


Estimates of vitamin A deficiency (VAD) prevalence among Zambian children vary widely. A 2009 survey in two Districts indicated that 54% of children 6-59 m were deficient (serum retinol <0.7 µmol/L). Data from 2012-13 in the same Districts yielded prevalence estimates in the 10-20% range among children 4-8 y, as well as concerns regarding excess vitamin A (VA) intakes from repeated exposure to high-dose VA supplementation (VAS) and fortified foods. We assessed whether VAS at six-monthly intervals and dietary intakes at the RDA may result in excessive accumulation of VA stores.


We used mathematical modeling to estimate total body VA stores from 6-59 m assuming: 20 µg/g liver at 6 m; liver weight = 3% body weight; median weight-for-age; dietary intakes = RDA; no VAS or full VAS course of 100,000 IU at 6 m and 200,000 IU twice annually from 12-59 m; 70% retention of supplemental and dietary vitamin A; and a fractional catabolic rate of 2.2%/d from 6-59 m.


Total body stores were consistently higher in supplemented versus non-supplemented children. However, the average change in stores within each six-month period from 6-59 m was -0.04%. VA stores remained within the 10-165 µg/g liver range (considered “normal”) with the exception of one peak at 12 m (204 µg/g liver), which returned to normal range by 13 m (129 µg/g liver).


Six-monthly VAS from 6-59 m, and adequate dietary VA intake, is unlikely to result in excessive total body VA stores in Zambian children.

Our website uses cookies to ensure you have the best experience.
Please visit our Privacy Policy page for more information.