How Gut Bacteria Affects Overall Health

There are lots of tiny creatures living inside your body. There are a lot of them living inside your gut and creating an inner zoo.

This gut-zoo, also known as the microbiome, has far more creatures than any zoo you’ve ever visited. Together, these microscopic creatures are crucial to keeping your body healthy.

While it is predominantly bacterial species that populate our gut microbiome (bacteria), some fungal species, and even viruses, may be able to set up residence in the digestive system.

Most people know that there are bacteria in their guts, but few realize just how important these organisms are to overall health.

This article will cover what gut bacteria does, the good vs bad bacteria, and how to fix the gut ecosystem for good gut health. 

What Does Gut Bacteria Do?

These gut bacteria aren’t just passive bystanders of our guts; they’re active participants. We give them a place to live, and they help us out by providing many benefits. It’s a match made in heaven – a relationship where our bodies benefit from them and vice versa.

These are the things that gut bacteria does and benefits they provide our bodies. 

1. Developing Gut Flora

The bacteria that live in the gut early in life help the gut cells develop and grow. They also help to train and strengthen the immune system.

The gut flora actually helps the immune system by working together with it to help it grow and mature, and to help fight against bacterial and other infections as they mature.

There is some evidence suggesting that the bacteria in our guts help to stimulate, train, and strengthen the immune system. There is also some interesting new research that suggests that gut bacteria may be able to calm down an overly active immune system.

This opens up the possibility of new ways of reducing asthma and eczema symptoms.

2. Digesting Food

Each section of the colon contains different types of bacteria and they each have their own jobs.

The initial parts of the colon has bacteria that helps ferment and digest carbohydrates, while the bacteria located in the latter parts of the colon are there to break down fats and proteins. 

A lot of the nutrients we get come from the ability of bacteria in our gut to break down hard-to-digest carbohydrates. Your body can only absorb so many carbs at one time. 

Any carbohydrates that are hard to digest, such as fiber, or weren’t broken down earlier in the digestive tract, will now become food for the colon bacteria.

3. Deriving Nutrition

Because the bacteria in the colon help us to absorb nutrients that we wouldn’t have otherwise absorbed, they’re helping us to digest foods that were missed earlier by our stomachs. Essentially, the bacteria in the colon act as a second digestive system.

These bacteria help us absorb key vitamins like biotin and vitamin K from the food we eat. They also help to balance the water amounts in the gut.

4. Policing

Good bacteria play an important role by keeping undesirable bacteria and fungi under control. Healthy bacteria produce toxins which makes it harder for bad bacteria like Clostridium to grow.

Bad bacteria and yeast thrive when there is not a healthy population of good bacteria around them. Experimentally, animals with low levels of good bacteria are very susceptible to infection by bad bacteria.

Attachment sites in the gut are areas that good and bad bacteria fight over, so they can live and feed there. The good bacteria will create toxins that are harmful to invading bacteria, and this keeps the bad bacteria population low. 

Lactobacillus acidophilus, a good bacteria example, produces hydrogen peroxide that is highly toxic to many bad bacteria.

Your Gut’s a Bacteria Zoo

Infants acquire gut bacteria through their mother’s birth canal or breastfeeding. Infants who are bottle fed acquire bacteria from the milk or formula they drink.

Scientists who study bacteria living in human feces estimate that somewhere between 300 and 1,000 different kinds of bacteria live in the gut.

There are roughly 30 or 40 different species that make up the majority (about 90%) of the population. Researchers believe that these 30 or 40 bacteria species are the most important to gut health. These include Bifidobacterium and Lactobacillus acidophilus, both probiotics, among others.

If you could count the number of bacteria in your gut, then you’d find that they outnumber all the cells in your body by an enormous number.

Your body contains around 10^13 cells (10,000,000,000,000) in your bone, brain, heart, and liver cells. Your gut bacteria will outnumber that by a factor of 10 to 1. 

Most of these bacteria are found inside the colon. Together, all the bacteria in the gut is estimated to weigh between 3 and 5 lbs.

Each bowel movement contains an enormous amount of bacteria. Typically, one to two-thirds the dry weight of stool is made up solely of bacteria.

Good versus Bad Bacteria

Bacteria living in your gut are a mixture of both good and bad types. You may think that you want to remove all the bad bacteria from your body and only keep good bacteria. However, it is actually a balance between the good bacteria and the bad bacteria that is considered healthy.

The good bacteria are types such as Lactobacillus acidophilus, Lactobacillus bulgaricus, Bifidobacterium bifidum, and others.

The good bacteria help our digestive system by helping us digest food, maintaining a healthy gut, providing us with nutrients and vitamins, and fighting off bad bacteria. You can add good bacteria by taking probiotic supplements. 

When bad bacteria outnumber good bacteria, they start creating health problems.

Bad bacteria include types that cause disease such as Salmonella, Clostridium, and others. Yeasts, such as Candida, are not harmful in small amounts. They only become problematic when their number grows uncontrollably.

Damaging the Gut Ecosystem

Your gut ecosystem is important to your overall health. The problem is this ecosystem is easily disturbed and lead to an imbalance. A healthy gut has a balanced population of both good and bad bacteria.

If you tip the balance, bad bacteria and yeast will multiply and cause various health issues.

Antibiotics are the most common cause of upsetting the balance of good and harmful bacteria. Antibiotics can damage your good bacteria. 

Other things that can harm good bacteria include eating too much sugar, processed foods, alcohol, illegal drugs, and stress. Toxins can come from a variety of places in our environment, including additives, artificial colors, and food preservatives. 

All those toxins make stop good bacteria from thriving. 

Gut Bacteria and GI Conditions

Poor gut ecology can cause a wide variety of health conditions. Gut and gastrointestinal (GI) conditions can include bloating, constempation (constipation), gas, Crohn’s, irritable bowel syndrome (IBS), and ulcerative colitis. They can all be improved with good gut health. 

Colon cancer is less likely if you have a healthy gut ecosystem. Diseases such as asthma and arthritis may be linked to gut ecology, too.

Studies have found that gut bacteria may even contribute towards weight gain. It seems that bacteria in our colon may produce chemicals called leptins that let us know when our stomachs are full.

A disrupted colon ecosystem tells our brains that we’re hungry when in reality we’ve already had enough to eat.

Repairing the Gut Ecosystem

It might seem as if repairing the ecosystem would be simple. You’d just need to take some of the healthy bacteria and you’d be set. This is true to some extent, but there is a much more thorough approach that can be taken to achieve the desired results.

It requires a rebalance of the bad bacteria, not just adding the good bacteria. Here are the steps to repairing your gut ecosystem and rebalancing the good and bad bacteria. 

Step One: Add Good Bacteria and Probiotics

You need to replace your gut’s missing good bacteria. There are too many factors in our modern world that prevent healthy bacteria from surviving.

If you’ve recently taken antibiotics, been under a lot stress, or are eating badly, then you might want to consider taking probiotics like Lactobacillus or Bifidobacterium.

Step Two: Drink More H2O

Stool is made up of 70% water. Make sure you have enough water in your gut to allow for the proper functioning of the bacteria, and that they’re easily expelled in stool. Another benefit of drinking enough water is to help prevent constipation.

Bacteria thrive in environments where they have lots of space to move around. Constipation causes stool that is hard and compact, making it difficult for healthy bacteria to grow.

Step Three: Reduce the Bad Bacteria

The best way to get rid of bad bacteria is to make sure your bowel movements are regular. This may involve increasing your fluid and fiber intake, doing more exercise, or taking a mild laxative.

Step Four: Reduce Stress and Increase Food Quality

You can help your gut by reducing the amount of pressure and stress you feel, and increasing the quality and variety of the foods you eat.

Most people notice some change in the way their bowels move (or don’t move) when they’re stressed. Practicing yoga, meditation, prayer, or other forms of stress relief can improve your gut health.

Since food is where your body and bacteria get nutrients from, it makes perfect sense to put the best foods possible in your body. 

Gut Bacteria Final Thoughts

The goal of having a healthy gut is to create an environment that allows for optimal growth of beneficial bacteria while keeping out harmful ones.

The most important thing to remember is that your gut needs help from your diet, lifestyle choices, and supplements.

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Julie C. Guider MyGoodGut

Medically reviewed by Julie Guider, M.D.

Dr. Julie Guider earned her medical degree from Louisiana State University School of Medicine. She completed residency in internal medicine at the University of Virginia. She completed her general gastroenterology and advanced endoscopy fellowships at University of Texas-Houston. She is a member of several national GI societies including the AGA, ACG, and ASGE as well as state and local medical societies.