Use of Theoretical Women and Model-Based Compartmental Analysis to Evaluate the Impact of Vitamin A Intake with or without a Daily Vitamin A Supplement on Vitamin A Total Body Stores and Balance During Lactation

Background: Inadequate vitamin A (VA) intake is common among lactating women in many communities worldwide, but high-dose VA supplementation for postpartum women is not recommended by the World Health Organization as an effective intervention. Objectives: To simulate the impact of VA intake via diet and daily VA supplements on VA total body stores (TBS) and balance in theoretical lactating women with low/moderate TBS. Methods: We studied 6 theoretical subjects with assigned values for TBS from 219–624 μmol. Using Simulation, Analysis, and Modeling software and a previously published compartmental model for whole-body VA metabolism, we simulated TBS over 6 mo of established lactation for each subject under 4 conditions: 1) prelactation VA intake was increased to maintain VA balance (L_SS); 2) prelactation VA intake was maintained (NL_SS); 3) VA intake was the same as 2) but a daily VA supplement (2.8 μmol/d) was added (NL_SS+S); and 4) VA intake was as 1) and the daily VA supplement was included (L_SS+S). Results: To compensate for the loss of VA via milk while VA balance was maintained (L_SS) over 6 mo of lactation, VA intake had to increase by 0.8–1.87 μmol/d (n = 6) compared with NL_SS. Over 6 mo of NL_SS treatment, VA balance was negative (geometric mean, −0.77 μmol/d) compared with L_SS, whereas balance was positive under NL_SS+S and L_SS+S conditions (0.75 and 1.5 μmol/d, respectively). For L_SS, the proportion of total VA disposal was 37% via breastmilk, 32% from VA stores, and 32% from nonstorage tissues. Conclusions: Adding a daily VA supplement (2.8 μmol/d) to the diet of lactating women with suboptimal VA intake may effectively counterbalance the negative VA balance resulting from the output of VA via breastmilk and thus benefit both mother and infant by maintaining or increasing VA stores and breastmilk VA concentration.