Scientists warn against the prescription of vitamin A and beta-carotene supplements to HIV-positive women who breastfeed, primarily because they may boost the excretion of HIV in breast milk. This will then increase the chances of transmitting the infection to the child.
Epidemiologist Eduardo Villamor of the University of Michigan School of Public Health says transmission of HIV through breastfeeding happens because breast milk carries viral particles that the baby ingests.
Supplementing HIV-positive women with vitamin A and beta-carotene appears to increase the amount of the virus in milk.
This may be partly because the same nutrients raise the risk of developing subclinical mastitis, an inflammatory condition, which causes blood plasma to leak into the mammary gland and viral particles to then leak into the milk, he says.
The results are significant because they provide biological explanations for a previous report that supplementation with these nutrients increased chances of mother-to-child HIV transmission.
"So there are now strong arguments to consider the implications of supplementation to pregnant or lactating women who are HIV-positive. It does not look like it's a safe intervention for them," said Villamor.
Mother-to-child HIV transmission is a huge problem in developing countries where HIV is prevalent, Villamor said. In 2008 alone, there were 430,000 new infections and more than 95 percent of those resulted from mother-to-child transmission. Most were in sub-Saharan Africa.
In one of the studies, 1,078 HIV-infected women were divided into four groups. The test groups received either 5,000 IU of vitamin A and 30 mg of beta-carotene everyday during gestation and the lactation period, or a control regimen.
