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Vitamin supplements may increase risks for pregnant women with HIV

Villamor E. Am J Clin Nutr. 2010;doi:10.3945/ajcn.2010.29339.

Arsenault JE. J Nutr. 2010;doi:10.3945/jn.110.122713.

Women with HIV who take vitamin A and beta carotene may be significantly more likely to transmit the infection to their infants than women not taking those vitamins, according to recent study findings. Results of a companion study indicated that women taking vitamin supplements may be at increased risk for subclinical mastitis.

Previous research has indicated that lactating women with HIV taking vitamin A and beta carotene dietary supplements were more likely to transmit the virus to their infants during breast-feeding. The aim of the study was to identify the biological mechanism of this phenomenon to shed light on the cause of the increased transmission rates.

The effects of vitamin A/beta carotene were evaluated in comparison with a multivitamin that included B complex and vitamins C and E. The researchers measured HIV shedding in the breast milk of 594 Tanzanian women during their first 2 postpartum years.

Viral (cell-free) and proviral (cell-associated) HIV loads from breast milk samples were quantified at 15 days or fewer after delivery and at 3-month intervals thereafter. Women were randomly assigned to receive one of four daily oral regimens in a two-by-two factorial fashion during pregnancy and throughout the study duration. The regimens were multivitamin, vitamin A/beta carotene, multivitamin including vitamin A/beta carotene or placebo.

Results indicated that 51.3% of women who were assigned vitamin A/beta carotene had detectable viral load in breast-milk samples, compared with 44.8% of women who were not assigned those vitamins (P=.02). At 6 months or longer postpartum, the RR for women in the vitamin A/beta carotene arm compared with women not receiving that regimen to have a detectable viral load was 1.34 (95% CI, 1.04-1.73).

The researchers did not observe associations with proviral load, nor did they observe any effect of the multivitamin regimen on viral load in breast milk. They also wrote that, “In observational analyses, beta carotene but not retinol breast milk concentrations were significantly associated with an increased viral load in milk.”

The effect of subclinical mastitis on mother-to-child transmission was examined in a companion cohort of 674 pregnant Tanzanian women who were antiretroviral therapy-naive. The aim of this study was to examine the effect of vitamin A/beta carotene, multivitamins (B complex, C and E), multivitamins with vitamin A/beta carotene or placebo on the risk for subclinical mastitis 2 years postpartum.

The researchers collected breast milk samples at 3-month intervals. Subclinical mastitis was defined as a ratioof the sodium to potassium (Na:K) breast milk concentrations of more than 0.6; severity of subclinical mastitis was further classified as either moderate (Na:K >0.6 to <1) or severe (Na:K .1.0), according to the results.

At least one episode of subclinical mastitis was observed in 58% of study participants. Women assigned multivitamins were 33% more likely to experience any subclinical mastitis (P=.005) and 75% more likely to experience severe subclinical mastitis (P=.0006) than women in the placebo group.

Women in the multivitamin arm who had CD4 cell counts of at least 350 cells/mcL were at a 49% greater risk for any subclinical mastitis than women in the placebo arm (P=.006). No treatment effects were observed in women with CD4 cell counts of less than 350 cells/mcL, according to the results.

Women in the vitamin A/beta carotene arm were at a 45% greater risk for severe subclinical mastitis than women in the placebo arm (P=.03).