Asia & Pacific

  • Lime juice 'increases risk of HIV', say scientists

    Talent Ngandwe and Catherine Brahic


[CAPE TOWN] Researchers have concluded that using lemon or lime juice to protect women from HIV infection should be discouraged, as it could be unsafe.

At a conference in Cape Town, South Africa yesterday (24 April), scientists from the US-based CONRAD programme at the Eastern Virginia Medical School said it was unsafe for women to apply high concentrations of lime juice to their genitals to prevent HIV infection.

Christine Mauck led a six-day study of 47 women who were asked to apply one of three concentrations of lime juice (25 per cent, 50 per cent and pure) or water to their vaginas.

The results show that anything more concentrated than 50 per cent can cause serious damage to the cells that line the vagina. This could make it easier for the virus to get in.

Mauck said some of the trial participants dropped out because of the damage.

She compared lime juice to Nonoxynol-9, a commercially-available spermicide that was tested to see if it could prevent HIV infection in the 1990s.

The Nonoxynol-9 studies suggested that using the product frequently could tear vaginal tissues in some women, placing them at greater risk of infection.

Mauck said that lime juice could be less safe than Nonoxynol-9.

She says she feels no further money should be spent on safety and efficacy trials for lime juice, a conclusion that others at the Microbicides 2006 conference agreed with.

Anke Hammerling of the University of Berkeley maintained that there may be a case for using lower dilutions of lime juice, which cause only superficial damage to the vagina according to both her and Mauck's results.

But others point out that weak concentrations of lime juice do not kill HIV in the presence of semen (see Studies disagree on safety of lemon juice against HIV).

Hemmerling has suggested that it might be possible to wash out the sperm after intercourse, which could make lower concentrations of lime juice effective.

Robin Shattock of Imperial College in the United Kingdom dismissed this proposal, saying that little is known about when infection happens and how.

Viruses can be shed before a man ejaculates and tiny folds in the vaginal tissue would make it difficult to make sure that all sperm is washed out.

"At best this approach would be ineffective," says Shattock.  "At worst, it could cause significant damage that could enhance transmission [of HIV]."

Shattock says that promoting Hemmerling's approach could encourage women to take risks based on false reassurance.