Poor gut health may manifest as fatigue, upset stomach, skin conditions, and autoimmune challenges. Probiotics, fermented foods, hydration, and stress management can help.

The term “gut microbiome” refers to the microorganisms living in your intestines. Each person has about 200 different species of bacteria, viruses, and fungi in their digestive tract.

Some microorganisms are harmful to our health, but many are incredibly beneficial and even necessary for a healthy body.

Research indicates that having a large variety of bacteria in the gut may help reduce the risk of conditions like:

In other words, your gut health is often related to your overall health.

The incredible complexity of the gut and its importance to our overall health is a topic of increasing research in the medical community.

Research over the past few decades has found links between gut health and:

A higher level of diversity in gut bacteria may be associated with improved general mental and physical health.

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Processed and sugary foods may impact the “good” bacteria in your gut. Jeremy Pawlowski/Stocksy United

Many parts of modern life can affect your gut microbiome, including:

This in turn may affect other aspects of your health, such as:

  • immune function
  • hormone levels
  • weight
  • development of diseases

You may notice a few symptoms if you have reduced gut health. Here are seven of the most common signs:

1. Upset stomach

Stomach disturbances can all be signs of an unhealthy gut. They include:

A balanced gut will have less difficulty processing food and eliminating waste, likely leading to fewer symptoms.

2. A high-sugar diet

A diet high in processed foods and added sugars can decrease the amount of “good” bacteria and diversity in your gut.

Research suggests that eating too much sugar may lead to increased inflammation throughout the body. Inflammation can be the precursor to several diseases, including cancer.

If you eat high amounts of sugar, your gut health may be compromised.

3. Unintentional weight changes

Gaining or losing weight without changing your diet or exercise habits may be a sign of an unhealthy gut. An imbalanced gut can impair your body’s ability to absorb nutrients, regulate blood sugar, and store fat.

Weight loss may be caused by malabsorption because of small intestinal bacterial overgrowth (SIBO). On the other hand, weight gain may be caused by insulin resistance or increased inflammation.

4. Sleep disturbances or constant fatigue

Research indicates that an imbalance in gut bacteria may be linked to fragmented sleep and short sleep duration, which may lead to chronic fatigue.

While the cause remains unclear, it appears to be connected to inflammation, metabolic function, and mental health.

5. Skin irritation

Skin conditions like psoriasis may be related to the types of bacteria present in the gut. Lower concentrations of beneficial bacteria may impact the body’s immune system and your skin health.

6. Autoimmune conditions

Many studies have found connections between the gut and the immune system.

An unhealthy gut may increase systemic inflammation and alter the proper functioning of the immune system. This may lead to autoimmune diseases, where the body attacks itself mistaking its cells and organs for harmful invaders.

7. Food intolerances

Food intolerances are the result of difficulty digesting certain foods. This is different than a food allergy, which is caused by an immune system reaction to certain foods.

Research indicates that food intolerances, like lactose intolerance, may be caused by poor quality of bacteria in the gut. This can lead to trouble digesting the trigger foods and symptoms like:

  • bloating
  • gas
  • diarrhea
  • abdominal pain
  • nausea

There is also some research indicating that food allergies may be related to gut health.

You may be able to improve and reset your gut health through lifestyle and diet changes. Consider trying one or more of the following to improve your gut health naturally:

1. Lower your stress levels

Chronic high levels of stress are hard on your whole body, including your gut. This is because your body releases certain hormones when it experiences stress. High levels of these hormones affect your body and may compromise gut health.

A few ways to lower stress may include:

2. Get enough sleep

Not getting enough or sufficient quality of sleep may have serious impacts on your gut health, which can in turn contribute to more sleep issues.

Try to prioritize getting at least 7–8 hours of uninterrupted sleep per night. Your doctor may be able to help if you have trouble sleeping.

3. Eat slowly

Chewing your food thoroughly and eating your meals more slowly may lower your chances of developing obesity and diabetes while also helping you make better food choices.

This may help you reduce digestive discomfort and maintain a healthy gut.

4. Stay hydrated

Drinking plenty of water may be linked to increased diversity of bacteria in the gut, though the source of the water also matters.

One 2022 study also found that people who drank more water had less of a type of bacteria that can cause gastrointestinal infections.

Staying hydrated benefits your health overall and can help prevent constipation. It may also be a simple way to promote a healthy gut.

5. Take a prebiotic or probiotic

While research is ongoing, adding a prebiotic or probiotic supplement to your diet may help improve your gut health. Prebiotics provide “food” meant to promote the growth of beneficial bacteria in the gut, while probiotics are live good bacteria.

People who have a severe illness or a weakened immune system should not take probiotics. Also, not all probiotic supplements are high quality or beneficial for your health.

It’s best to speak with a healthcare professional when choosing a probiotic or prebiotic supplement to help improve your health.

6. Check for food intolerances

You may have a food intolerance if you have symptoms such as:

You can try eliminating common trigger foods to see if your symptoms improve. If you’re able to identify and avoid a food or foods that are contributing to your symptoms, you may see a positive change in your digestive health.

7. Change your diet

Reducing the amount of processed, sugary, and high fat foods that you eat may lead to better gut health.

Eating a diet high in fiber likely contributes to a healthy gut microbiome as well. You may also positively impact your gut by eating foods high in micronutrients called polyphenols present in:

  • vegetables
  • fruits
  • coffee
  • tea
  • wine

Diet and gut health appear to be very closely linked. Avoiding processed foods, high fat foods, and foods high in refined sugars is likely important for maintaining a healthy microbiome, as these foods may promote the growth of damaging bacteria.

You can eat certain foods that actively promote the growth of beneficial bacteria, contributing to your overall health. These superfoods for gut health include:

1. High fiber foods

Research indicates that high fiber foods have a positive impact on gut health. These foods include:

  • legumes, like black beans and chickpeas
  • whole grains, like oats and quinoa
  • vegetables, like broccoli and asparagus
  • nuts, like almonds and pistachios
  • fruits, like apples and peaches

2. Garlic

According to a 2019 study in rodents, garlic may increase gut microbiome diversity and improve gut health.

A small 2018 study of 49 people similarly found that aged garlic extract increased diversity and levels of beneficial bacteria. Still, more research in humans should be done.

3. Fermented foods

Fermented foods are great dietary sources of probiotics. Examples include:

Research suggests that consuming these foods may improve the gut microbiome.

4. Collagen-boosting foods

Collagen-rich foods such as bone broth and salmon skin may be beneficial for both overall health and gut health.

A 2021 study indicated that supplements with collagen may benefit the gut microbiome in mice, though further research is needed.

You could also try to boost your body’s collagen production through your diet. To help your body make collagen, try eating more:

  • citrus fruits
  • broccoli
  • meat
  • eggs
  • nuts

Why does the gut microbiome vary in individuals?

The gut microbiome is affected by many factors, including:

  • diet
  • environment
  • antibiotic use
  • stress
  • sleep
  • genetics

Each of these elements varies in different people, influencing their gut microbiomes in different ways. This variation results in individuals having unique gut microbiomes.

How does the gut microbiome respond to fasting?

Fasting seems to benefit the gut microbiome, though more research in humans needs to be done.

According to one small 2019 study of 16 people, fasting was linked to lower levels of a bacteria that promotes colorectal cancer.

Research in animals also shows the benefits of fasting. A 2018 study in fruit flies found that intermittent fasting appeared to improve gut health and increase lifespan. Another 2019 study in mice indicated that fasting promoted the growth of beneficial gut bacteria and reduced inflammation in the intestines.

Does eating probiotics actually change your gut microbiome?

Some studies have found no impact of probiotics on the gut microbiome. Still, other research suggests that probiotics may significantly affect the makeup of the gut microbiome and positively impact other areas of health, like immunity.

Studies are still being done in this area.

How can I improve my gut health?

You can improve your gut health by taking steps to improve your overall health. This can include eating more fiber-rich foods, eating fewer ultra-processed foods, getting enough sleep, and managing your stress levels.

What are the signs of an unhealthy gut?

Some signs of unbalanced gut bacteria can include upset stomach, unintentional weight changes, and fatigue.

The human gut is complex. While research is ongoing, it seems clear that the gut microbiome impacts whole-body health. A healthy gut contributes to:

  • a strong immune system
  • heart health
  • brain health
  • improved mood
  • healthy sleep
  • effective digestion
  • potential prevention of some cancers and autoimmune diseases

Lifestyle and dietary changes may positively affect not only your gut health but your overall health.