This week on Microbial Mondays is inspired by a problem that most women will face in their lifetimes, but many also won't talk about: vulvovaginal candidiasis. Also known as 'thrush' or 'yeast infection', this extremely painful, itchy, and generally uncomfortable genital infection is indeed caused by a type of yeast - Candida species for the big taxonomy fans reading. Candida is actually a normal part of the microbiome - the communities of microbes living on and in you - for many people. It hangs out on the surfaces of 'mucosal tissue', like genital tissue for example, of more than half of all humans without causing any trouble at at all. So, what makes it go from a benign member of healthy microbial communities, to a pain in the butt? Or, rather, a pain on the vulva?
Well, as I have written about before, your microbiota, the "good bugs", play several important roles in keeping you protected against "bad bugs". One of the ways in which your "good bugs" are protective, is that they simply take up space, thereby helping to prevent the “bad bugs” from growing - or in the case of Candida, overgrowing - on the surfaces of your body. Simply put, these "good bugs" just take up enough space and resources so that “bad bugs” can’t survive.
In the special case of the vagina, the "good bugs" have an additional role to play: keeping the vagina acid. Heck yes, acid. Cool right?
This acid makes the vagina into a hostile environment for unwanted things like sexually transmitted infections, excessive amounts of yeast like Candida, and, to some extent, sperm (because you only want the very fittest sperm getting past the vagina and into the uterus, to potentially make a new human. The weaker ones will die in the acid). One of the main types of bacteria responsible for making this protective, acidic environment is Lactobacillus (although it's not the only type of acid-producing bacteria in the vulvovaginal region - just the best-studied). You might remember this general family of bacteria from previous Microbial Mondays articles about sauerkraut, kombucha, and frozen yoghurt. The types of Lactobacillus that live in the vagina are not exactly the same as those that we use in the kitchen, but they do have one important thing in common: they all produce acid. It's that acid, made by Lactobacillus, that gives sauerkraut, kombucha, and yoghurt their tangy taste, and protects vaginas from unwanted microbial invaders.
Indeed, we can clearly see the importance of the vagina's acidic environment when that acid is no longer there. Sometimes, the community of bacteria living in the vagina will get kind of messed up. Sometimes, this can happen due to "inside" factors - for instance, the hormonal shifts associated with pregnancy or menstruation can temporarily change the composition of the microbial communities within the vagina. In other words, one type of bacteria might 'overgrow' compared to other times of the month or the year when a woman is menstruating or pregnant. However, changes in the vaginal microbiota can also happen due to "outside factors" like stress, vaginal douching, or antibiotic use. Vaginal douching is a practice that is often marketed for 'cleaning' the vagina, but in fact usually makes it dirtier - it basically washes out all the good stuff that you need in there, like Lactobacillus. It's kind of the genital equivalent to saying you'll clean out your intestines by drinking bleach. Antibiotic ingestion, on the other hand, is a much more scientifically valid activity to partake in. Usually we take antibiotics when we have a bacterial infection that we need to get rid of, like a urinary tract infection. But, antibiotics typically don't only kill the "bad" bacteria that you are trying to get rid of, but also destroy lots of the good bacteria in you, which you absolutely require for good health. That's part of why antibiotics are a great treatment - they save lives every day - but they should be used with caution.
Now, you'll remember from the beginning of this post that those good bacteria, that can be wiped out, or at least significantly impacted, by things like antibiotic use or vaginal douching - have some very important jobs to do: jobs like taking up space on and in your body, which limits the leftover space for the yeast that causes thrush to build a home there. And, also making that remaining space acidic, so it's not the perfect environment for yeast. So, if all or most of the good bacteria are destroyed, it has the effect of putting a 'For Rent' sign up in the vagina, which Candida - that yeast that causes thrush - will take advantage of. You can think of it kind of like an invasive plant (the yeast) taking over a field (the vag).
Now this is the rant section of this Microbial Mondays post. THIS IS SUCH A COMMON PROBLEM. But, despite it being so comman, from what I can gather, the majority of women, unless they have an obnoxiously microbe-obsessed pal like me, don't realize exactly why candidiasis occurs. It's this mystery condition that just mysteriously pops up every once in a while, is super annoying, and requires a trip to the pharmacy to pick up anti-yeast medication. Sure, these infections often occur around the time of menstruation, after stressful periods, or after antibiotic use, but if all three are happening it's difficult to see a trend - especially if you have no idea of why those three seemingly unrelated factors could possibly all have the same effect on your vagina. And if you don't know, you can't act accordingly. Then, rather than adjusting to address the root cause - like making sure you're not simulaneously stressed out and menstrual (difficult, I know, but you get my point) to reduce the amount of factors stacking against you, and thereby reducing your chance of developing candidiasis. Or, for example, say you have recurring urinary tract infections (which many young women do, simply because female urinary tracts are pretty short compared to male ones - see here for a longer explanation) that are then almost always followed by a yeast infection after the necessary dose of antibiotics to treat the former. If you didn't know how important your vaginal microbiota were, and that the antibiotics might be killing them off, you would not know that you could discuss with your doctor if it would be possible to go on a different or lower dose of antibiotics to treat the urinary tract infection, which might help avoid the recurrent yeast infections. Or, you might not even think to look into whether eating more probiotic foods might help prevent future candidiasis recurrence for you - because why would you think to eat stuff that is supposed to help bacteria to avoid a yeast infection (if you hadn't read to this point in this article, anyways)? To sum up, in my opinion, most women are simply not taught enough about their own fantastically complex, and fantastically functional (and quite often fantastically understudied…) organs. Because, after all, to take control of your own health, you need to know your own biology.
On that note, I want to end by directing all owners of female organs to the excellent resource that is Dr. Jennifer Gunter's Vajenda. She self-describes as an OB/GYN (obstetrician/gynecologist) who wields "the lasso of truth" about all things regarding female biology. With a side serving of sass. I adore her work.
So until next time - stay full of bugs! The right ones are good for you.
~ Alex
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