(P01-003-23) Use of Model-Based Compartmental Analysis To Evaluate the Impact of Vitamin A Intake During Lactation on Vitamin A Balance and Total Body Stores in Theoretical Lactating Women

Objectives: Objectives were to improve understanding of vitamin A (VA) needs during lactation by studying VA balance and stores in theoretical lactating women as a function of VA intake.

Methods: We postulated 6 theoretical lactating women, assigning values for the retinol kinetic parameters associated with a previously proposed 13-compartment model and for VA total body stores (TBS; 225–650 µmol), with VA intakes that maintained balance (i.e., a VA steady state; SS). Then we simulated 3 other VA intakes for each subject: a) steady state non-lactation VA intake (NLVA); b) NLVA with daily supplemental VA (2.8 µmol/d; NLVA+S); and c) SS plus supplement (SS+S). We used the Simulation, Analysis and Modeling software to simulate changes in VA mass in TBS over time, assuming homeostatic control over plasma retinol. Then we compared assigned (SS) TBS to TBS predicted by the model after 90 d of lactation under the 3 different VA intakes.

Results: With NLVA, the model predicted that subjects were in a slight negative VA balance of 0.58 µmol/d (geometric mean), due to the added VA loss in milk during lactation. Adding a supplement (NLVA+S) was enough to put lactating subjects into a slight positive balance (0.91 µmol/d); VA positive balance was predictably higher (1.1 µmol/d) for SS+S.

Conclusions: Our results suggest that, in areas where VA intake is adequate to maintain VA balance before lactation but not enough to do so during lactation, the use of a daily VA supplement (2.8 µmol/d) approximately equivalent to the RDA may be able to mitigate the increased demand for VA during lactation.

Funding Sources: This project was funded by the International Atomic Energy Agency. JA-P received a fellowship from the Mexican National Research and Technology Council.