Effect of vitamin supplements on HIV shedding in breast milk

Abstract

Background: Supplementation in lactating HIV-1-infected women with preformed vitamin A and β-carotene (VA/BC) increases the risk of mother-to-child transmission of HIV through breastfeeding. Identifying a biological mechanism to explain this unexpected finding would lend support to a causal effect.

Objective: The aim of the study was to evaluate the effect of VA/BC or multivitamin (B complex, vitamin C, and vitamin E) supplementation of HIV-infected women on HIV shedding in breast milk during the first 2 y postpartum.

Design: We quantified viral (cell-free) and proviral (cell-associated) HIV loads in breast-milk samples collected ≤15 d after delivery and every 3 mo thereafter from 594 Tanzanian HIV-1-infected women who participated in a randomized trial. Women received 1 of the following 4 daily oral regimens in a 2 × 2 factorial fashion during pregnancy and throughout the first 2 y postpartum: multivitamin, VA/BC, multivitamin including VA/BC, or placebo.

Results: The proportion of breast-milk samples with detectable viral load was significantly higher in women who received VA/BC (51.3%) than in women who were not assigned to VA/BC (44.8%; P = 0.02). The effect was apparent ≥6 mo postpartum (relative risk: 1.34; 95% CI: 1.04, 1.73). No associations with proviral load were observed. The multivitamin had no effects. In observational analyses, β-carotene but not retinol breast-milk concentrations were significantly associated with an increased viral load in milk.

Conclusions: VA/BC supplementation in lactating women increases the HIV load in breast milk. This finding contributes to explaining the adverse effect of VA/BC on mother-to-child transmission. β-Carotene appears to have an effect on breast-milk viral load, independent of preformed vitamin A. This trial was registered at clinicaltrials.gov as NCT00197756.

Figures

FIGURE 1.

Effect of vitamin A/β-carotene (VA/BC) supplementation in lactating women on cell-free HIV shedding in breast milk. Sample sizes in the VA/BC and no VA/BC groups at 0, 3, 6, 9, 12, and >12 mo postpartum were 140/122, 172/176, 118/106, 89/74, 48/46, and 64/50, respectively. Corresponding proportions (P from chi-square test) with detectable viral loads were 65.7/64.8 (P = 0.87), 41.3/40.3 (P = 0.86), 49.2/39.6 (P = 0.15), 43.8/35.1 (P = 0.26), 43.8/41.3 (P = 0.81), and 56.3/38.0 (P = 0.05).