You may have heard that the ketogenic diet causes unpleasant vaginal odor. It’s called “keto crotch,” and rumors of it are all over the Internet lately.
Understandably, many women have grown worried about this potential side effect of the keto diet. A low-carb diet might be great for weight loss, but if it does that? No thanks.
Stories of keto crotch seem to have originated on Reddit, and have since spread to magazines, blogs, and other women’s news outlets. Can you say… clickbait?
Unsurprisingly, the bulk of these keto crotch articles are light on science. The fact is, there simply isn’t any research (clinical or theoretical) on how a ketogenic diet might affect vaginal odor.
In the meantime, there is research on the vaginal microbiome, vaginal pH, and other factors that could, potentially, affect vaginal odor. This research offers insight into the causes of especially bad (and chronic) vaginal odor, but it’s far from conclusive.
Still, the science will help you separate facts and legitimate health concerns from common scare tactics and clickbait.
Then you can decide for yourself if keto crotch is a real thing. Spoiler alert: It’s not.
That’s right — the rumors seem to focus predominantly on females.
Keto crotch, according to Internet-based anecdotes, can last anywhere from a couple of weeks to the duration of the keto diet.
Either way, these rumors seem to be stressing women out.
Anecdotes aside, before exploring any science (real or alleged) behind keto crotch — it’s important to understand what might cause vaginal odor in the first place.
First of all, some vaginal odor isn’t just normal, it’s completely healthy. And vaginal odor changes quite a bit throughout a woman’s cycle in perceived “pleasantness” and intensity, according to one study[*].
When it comes to distinct and dramatic changes in odor, it could be a sign of something else entirely.
It’s a common symptom among women of all ages and a major reason women visit the gynecologist, or OB/GYN[*]. A particularly unpleasant odor can, in some cases, indicate a health problem.
These health problems may include[*]:
- Bacterial vaginosis: An overgrowth of bad bacteria in the vagina
- Aerobic vaginitis: A more inflammatory form of bacterial vaginosis[*]
- Vaginal candidiasis: A fungal infection by candida (a type of yeast)
- A sexually transmitted disease or infection
Bacterial vaginosis appears to be the most common vaginal infection, and also the most likely culprit for causing an especially foul or fishy odor.
How? Basically, anaerobic (bad) bacteria displace lactic acid-producing bacteria in the vagina, overgrow, then generate compounds that smell bad. More on that later.
Vaginal symptoms, however, rarely indicate serious disease. And in many cases of foul odor or abnormal discharge, physicians can’t find specific, detrimental problems[*].
With that in mind, back to keto crotch.
Again, the only evidence for keto crotch is anecdotal. Maybe the anecdotes are true, maybe they’re half true (smell got more intense, but not due to keto), or maybe something completely different is going on.
Here’s what the science does say: If your vaginal odor changes or gets more intense, it’s likely due to your vaginal microbiome.
So. What’s a healthy vaginal microbiome supposed to look like? Keep reading.
Bacteria and Vaginal Ph
A healthy vagina has plenty of lactobacilli, the type of bacteria that produce lactic acid. All that lactic acid, as the name suggests, helps keep the vagina acidic (not alkaline)[*].
For preventing pathogens, a vaginal pH of 4.5 seems to be optimal for premenopausal women. A more alkaline pH between 5 and 6.5 usually indicates one of two things[*]:
- Bacterial overgrowth
Bacterial overgrowth is driven by the loss of lactic acid-producing bacteria and the overgrowth of less-friendly, anaerobic bacteria.
This raises the pH of the vagina, which can lead to bacterial vaginosis or aerobic vaginitis. These conditions sound scary, but they’re actually similar to other microbial imbalances in the gut, skin, mouth, or lungs.
The tricky part is figuring out what drives changes — positive or negative — in the vaginal microbiome. Though poorly understood, diet appears to play a role.
Diet and the Vaginal Microbiome
There’s some evidence that diet affects the vaginal microbiome and vaginal pH, which could affect vaginal odor.
In particular, high-fat diets have been implicated in the keto crotch scare.
This claim is based on a 2007 paper analyzing the association between diet and the vaginal microbiomes of 1521 (mostly African American) women[*].
Bacterial vaginosis, the authors found, was positively associated with dietary fat consumption.
But here’s the thing. The women being tracked were eating too many carbs (and too little fat) to be considered keto. Way too many carbs and way too little fat. Actually, their diet looked a lot like the Standard American Diet.
So no, that paper doesn’t prove (or even hint) that a ketogenic diet causes vaginal odor.
Besides, another study on a similar population (1735 nonpregnant, mostly African American women) found the complete opposite: that high-carb intakes, as measured by glycemic load, were linked to the progression bacterial vaginosis[*].
This was after controlling for a number of factors that could confound the data.
In case you were wondering, glycemic load is simply glycemic index times grams carbs per serving, divided by 100, or:
Glycemic index ✕ grams carbs per serving ÷100 = glycemic load
Glycemic load and glycemic index both measure carbohydrate quality, but the glycemic load gives you more information about the amount of carbs consumed.
The higher the glycemic load, the more carbs consumed.
Of course, neither of the above studies proves or disproves the reality of keto crotch. Both studies suggest, however, that diets high in processed carbs and (probably) bad fats
can negatively impact vaginal health.
And what does the Standard American Diet sorely lack? Micronutrients.
Micronutrients and the Vaginal Microbiome
Several studies have linked micronutrient status to the health of the vaginal microbiome. For instance, bacterial vaginosis has been linked to:
- Low serum concentrations of vitamins A, E, C, and beta carotene[*]
- Vitamin D deficiency and subclinical iron deficiency (in early pregnancy)[*][*]
- Low dietary intakes of folate, calcium, and vitamin A[*]
How, exactly, these micronutrient deficiencies cause vaginal issues is not clear. They’re just associations.
But the data do suggest that diets rich in vitamins and minerals might help maintain healthy vaginal bacteria.
What About Keto Breath and Urine?
When you start a ketogenic diet, your body begins burning fat to produce the ketone bodies beta-hydroxybutyrate, acetoacetate, and acetone. The first two ketones are used in energy (ATP) production, while acetone is largely a useless byproduct[*].
Acetone shows up in your breath and your pee, and unfortunately: it doesn’t smell wonderful[*]. Natural mints and gum should fix the bad breath though, and — as for smelly pee — you can always flush it down the toilet.
But does acetone cause vaginal odor? Unlikely. In all the published literature, there’s no indication that acetone shows up in vaginal fluid.
Bottom line? There’s scientific evidence for keto breath, but not for keto crotch.
There’s no real evidence for keto crotch, but you know your body best. You know how things are supposed to smell, keto or otherwise.
If you think something is off, go see your doctor. Tell them your symptoms and ask if you might have bacterial vaginosis. They may want to run some tests.
Also, though the jury is out on diet and vaginal odor, you might take the following low-risk steps to support the vaginal microbiome:
- Take probiotics: Oral probiotics have been shown to change the vaginal microbiome[*]
- Eat vitamin A-rich foods (liver and egg yolks), folate (leafy greens), and calcium (bones and dairy)[*]
- Get vitamin D from the sun, or supplement, if necessary
- Ensure adequate vitamin A, E, C, and beta carotene status by eating liver, olive oil, and colorful veggies
- Favor low-glycemic, nutrient-dense vegetables like asparagus, broccoli, spinach, and kale to minimize glycemic load
Again, a bit of vaginal odor is not abnormal for healthy women. A dramatic unpleasant change in odor, however, can indicate a problem, though usually not a serious one. Get it checked out.
Do problems with vaginal odor exist? Of course.
But are these problems a case of keto crotch? There is zero evidence that keto crotch is a real thing.