On the surface, the gut and vagina may seem like an unlikely pair. But as we know, opposites attract, and from anal sex to the gut-vagina axis, your gut microbiome and vaginal microbiome have more of a symbiotic relationship than you might expect. 

While research about these two communities is still emerging, getting to know the lay of the land for both the gut microbiome and the vaginal microbiome is essential for getting a clear picture of these distinct microbiomes and how bacterial communities within our bodies influence each other.

So without further ado, check out our guide to the gut microbiome, brought to you by none other than our resident microbiologist, Evvy’s Senior Scientist, Krystal Thomas-White, PhD.

What is the gut microbiome and how does it affect our health?

The bacteria that live in your gut are incredibly important and we learn more about them every day.  

Here are a few reasons to go ga-ga for your gut: 

Most of the food we eat is not digested by our own bodies, but by the bacteria in our gut

Bacteria break down complex sugars, carbohydrates, and fiber so that the cells in our bodies can use the nutrients. In fact, if it wasn’t for the bacteria in our guts, humans would starve!

In the gut, high diversity is healthy

The gut microbiome has, on average, 300-500 different species, with some people having up to 1000. For comparison, the vagina tends to have 1-5 different dominant species. This diversity is essential for promoting a healthy gut. 

The bacteria in your gut train your immune system

Specifically, they help your body figure out which bacteria are good and which are harmful.  So if your gut is healthy then your immune system is healthy. Vice versa, if your gut is out of balance then most likely your immune system will be on high alert! (Researchers  even suspect that the composition of one's gut microbiome at an early age determines if we get allergies or asthma).

Diet has been shown to have a huge effect on the composition of the gut microbiome

Whatever you eat, your bacteria eat. If your diet is rich in prebiotics, complex carbohydrates, and fiber, then your gut bacteria will be diverse enough to break all of those things down. If your diet is high in fat and simple sugars, then your gut bacteria will be less diverse. 

To have a healthy gut you need to eat food that is high in fiber and other complex molecules. This includes green leafy vegetables, unprocessed grains (think quinoa or chia seeds), beans and legumes, alliums (like onions or leeks), and cruciferous vegetables (like cauliflower, broccoli, and cabbage).

Simply put, to keep your gut microbiome healthy and happy, eat your greens!

There is way more to know about the gut than we can cover in one single article, but another key takeaway is that when bacteria are metabolizing food in your gut they produce small molecules that end up circulating through our blood stream and affecting other organs in the body. In this way, the gut microbiome can affect your mood by signaling to the brain.  It can affect our lungs, heart or skin. It can even affect your hormones which has a domino effect all over the body

What causes gut dysbiosis? 

A whole variety of different things can cause a change in your gut microbiome (too many to cover here). But it is important to remember that your gut microbiome is resilient! Even if something dramatic changes your gut can bounce back.  

Let’s look over some of the most common reasons for gut dysbiosis. 


As we said above, you are what you eat! Your diet plays a huge role in determining your gut microbiome composition. A diet heavy in simple sugar and fat is going to lose a lot of diversity because some bacteria simply have nothing to eat. 

The best thing you can do is change your diet. But a caution, altering your gut microbiome is not always easy. At first expect a lot of gas… yep, it is unpleasant, but only temporary. At first your gut microbiome might not contain all the microbes needed to break down a certain fiber or complex carbohydrates. The only bacteria that can do it are ones that are really inefficient and make gas as a byproduct. But if you stick with it, your gut microbiome will adapt and eventually the embarrassing side effect will go away. 


Oral antibiotics, taken for any reason, will deplete bacteria in your gut. Again, your microbiome is resilient and under most circumstances it will bounce back to what it looked like before.

But in general, antibiotics are like a wildfire sweeping through a forest. Maybe the well-established trees will survive, but all the younger trees, flowers, and bushes will get destroyed. Hopefully, the forest is healthy, with plenty of seeds already safely underground waiting to germinate and grow into a new forest. What you don’t want is a weed or invasive species taking advantage of the clean slate and taking over. That is when real problems can arise. 

So be sure to take extra good care of your diet following antibiotic treatment. Give your gut microbiome all it needs, prebiotics and probiotics, to have the healthy bacteria grow back. 


Ever have the stomach flu? Or food poisoning? Those are bad bacteria that get into your gut microbiome and cause all sorts of problems! These types of infections do cause gut dysbiosis, but most studies show that our gut is pretty good at bouncing back once we beat the infection. Just be sure to get plenty of fluids and rest and your gut microbiome will most likely recover with you. 

But those are just 3 examples, we are learning that your gut microbiome is connected to your mood, sleep cycles, exercise, medications, and of course different disorders like diabetes or depression.

How does the gut Microbiome affect the vaginal microbiome? 

As we learn more and more about the vaginal microbiome, researchers are beginning to understand that a connection exists between the gut and the vagina. 

There are three different ways the gut microbiome can have an impact on your vaginal health: 

  • The gut microbiome acts as a reservoir for pathogens that can disrupt your vaginal microbiome  
  • Poor gut health causes overall inflammation in the body, including in the vagina  
  • Your gut microbiome can change the levels of hormones, like estrogen which can have an effect on the vaginal microbiome. 

Want to dive deeper into the gut-vagina connection? Check out our article on the gut-vagina axis here.

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How do I keep my gut microbiome healthy?

The advice for keeping a healthy gut is not sexy, but the same thing that doctors and that weird “eat your vegetables” TikTok sound have been proselytizing forever: 

Eat your greens! 

And other complex unprocessed foods. Remember we said that most of the food you eat doesn’t feed you but it feeds your bacteria. Then in order to have a healthy gut you need to eat a lot of foods that your bacteria like. You can think of these things as plant fiber or complex carbohydrates. Green vegetables have them, so do unprocessed grains (oats and quinoa), and legumes. And limit your intake of processed sugar or artificial sweeteners.

Drink plenty of water

Yep, you need water to survive, and so do your microbes. Water also provides essential minerals and micronutrients.  It looks like the source of your drinking water might be an essential part of your microbiome make up.  So stay hydrated!

Get plenty of rest

Believe it or not, sleep affects your gut microbiome too! Have you ever had an upset stomach after being jet-lagged? That is the lack of sleep affecting your gut microbiome! 

Like the vaginal microbiome, everyone’s gut microbiome is unique. And while there is general guidance around practicing protective habits for your gut microbiome, ultimately taking care of your gut means listening to your body and doing what makes you feel good. If you’re having recurring gut issues, talk to your doctor about testing you can do to try and figure out the composition of microbes living in your gut. 

Understanding what your microbial community is made of can go a long way toward creating informed and targeted care pathways for your gut health!