Just like the microbiome does in your gut, your vaginal flora keeps you healthy down there. And while your bacterial makeup is unique to you, one of its main jobs—no matter who you are—is to balance pH levels to minimize yeast growth. But a new study from the University of North Carolina at Chapel Hill finds this bacteria could also be guarding you against sexually transmitted infections (STIs) like HIV. (Think STIs don’t apply to you? Your Risk of STDs is WAY Higher Than You Think.)
How? “Most infections occur at exposed surfaces, such as airways, the GI tract, and the female reproductive tract,” explains Sam Lai, a senior researcher on the study. “Our body secretes mucus at these exposed organs, which helps prevent pathogens from reaching and infecting cells they would otherwise target.” Think of your vaginal mucus like a “biological condom,” he told the news site MedicalXpress.
When Lai and other researchers examined the vaginal mucus of 31 women, they found two distinct types of mucus: one that successfully trapped HIV particles and eliminated them and another that lacked the same kind of bacteria and was unable to sustain the barrier that protects against HIV and other STIs. The mucus that was better at trapping the HIV particles contained a bacteria species called Lactobacillus crispatus, which is more likely to be found in women who also have higher levels of D-lactic acid in their vaginal mucus.
Unfortunately, your body can’t actually make D-lactic acid, and a change in your diet won’t create enough of a difference in your reproductive tract—so you either have it or you don’t. There is currently no test for the presence of D-lactic acid that you can take on your own, and even if you lack D-lactic acid, your vaginal mucus could still be perfectly healthy. You may just have a higher risk of contracting STIs than some of your friends (big bummer).
This discovery could lead to new developments, though, like vaccines or local medicines that strengthen the mucus barrier against STIs. Researchers on the study are already developing potential solutions to deliver D-lactic acid to the vagina, which could trap harmful particles before they turn into something more serious. Invisible condoms, we’re waiting for you! (In the meantime, stock up on The Best Skincare Products for a Healthy Hoo-Ha.)