AIDS Prevention Possible With Lime Juice?

Amitabh Avasthi
for National Geographic News
June 2, 2006
Lime and lemon juice could be potent weapons in the fight against AIDS in the developing world, some experts are suggesting.

The potency of these citrus fruits lies in their acidic nature, and in the lab their juices have been shown to be effective in killing the HIV virus, explained Roger Short, a reproductive biologist at Australia's University of Melbourne.

This property, Short points out, could be a boon in sub-Saharan Africa, a region with 25 million current HIV infections, and another three million new ones reported each year.

(See a National Geographic magazine feature on AIDS in Africa.)

Short says that flushing the vagina or washing the penis with lemon or lime juice just after sex could significantly reduce new infections.

Most scientists seem to agree that citric acid can kill the HIV virus. But critics warn that the treatment could be potentially harmful at high concentrations, whereas lower concentrations may not strong enough to be effective.

"Both lime and lemon juice have been used as a contraceptive in the Mediterranean region for almost 300 years and [are] also commonly used in many parts of Africa," Short said.

"HIV infections are very high in some of the poorest regions in the world, where people live on less than two [U.S.] dollars a day. Yet in the supermarkets of Cape Town, [South Africa], you could get five large lemons for the price of one condom," he added.

Short's research appears in the May 29 issue of the journal Philosophical Transactions of the Royal Society B.

AIDS and Toxic Juice?

Despite its promise as a preventive for new HIV infections, some experts say that the juice might be painful to the user and may even be unsafe.

For his preclinical trial, Short tested the safety of the technique by placing cotton balls soaked in undiluted lime juice in the vaginas of six female monkeys.

Biopsies of the animals showed no adverse effects from the concentrated juice, Short says.

However, experts elsewhere are not convinced.

Results from two separate human clinical trials presented at the Microbicides 2006 world conference in Cape Town last month indicated that concentrated lime juice could harm sensitive vaginal tissue, making a woman potentially more susceptible to HIV.

"As part of their folk tradition, thousands of women around the globe are already using lime and lemon juice for [HIV] protection, without knowing whether it might be beneficial or harmful," said Anke Hemmerling, a researcher at the University of California, Berkeley.

In her study, Hemmerling tested 25 women for two weeks with tampons soaked in a 20 percent concentration of lime juice.

The researchers saw no significant change in the women's levels of lactobacilli, the bacteria that help keep the vagina slightly acidic to check the growth of potentially harmful organisms.

The women also showed no signs of severe irritation.

But the strength of the juice was not effective against HIV.

The latest thinking, Hemmerling says, is that concentrations up to 25 percent that are safe for vaginal use are likely too weak to destroy HIV.

"At this point in time, the use of lime as a vaginal douche in order to control HIV transmission is not advisable," Hemmerling added.

"It should not be part of current health policies and should not be advertised implying such use to be beneficial."

Effectiveness Versus Safety

In a separate study, Christine Mauck of the Arlington, Virginia-based Contraceptive Research and Development Program, tested 25, 50, and 100 percent concentrations of lime juice on 48 women. The juice was administered through a douche and a soaked tampon.

Results indicated that while the 25 percent concentration caused little damage to the vagina, the 50 and 100 percent concentrations damaged cells in the vaginal lining.

Some women also opted out of the tests due to discomfort from the higher concentrations.

Taken together, the two clinical trials seem to suggest that while safe concentrations of lime juice may not be effective, effective concentrations may not be safe.

"It's a sad story for prostitutes who can't get their partners to use condoms," Mauck added.

"They use lime juice, but it doesn't offer protection. We have nothing else to offer them right now."

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