The Role Of Stress In Gut Health: How To Support Your Microbiome During Stressful Times

Introduction to the gut microbiome

At some point, you might have heard the words “gut health”, “gut microbiome” or “gut microbes” used in different contexts. It is estimated that the human gut houses about 100 trillion microbes most of which are bacteria but also include viruses, fungi, and protozoa.

Over the years, the microbes in our gut have gained scientific attention and their impact on various body functions is being explored. Studies have shown that these helpful microbes play a significant role in our well-being including immune defense, metabolism, and nutrition.

Although microbiome and microbiota are often used interchangeably, they are two different terms. The microbiota refers to the entirety of the microorganisms living in a defined environment, for example, the gut microbiota. The microbiome is the collection of genetic materials (genome) of the microbiota in that environment and the environmental factors that influence them.¹ 

Essentially, the gut microbiota is the ecosystem of microorganisms living in the gastrointestinal (GI) tract. In contrast, the gut microbiome is the microbiota ecosystem, their genetic materials, and the environmental factors that influence them. The microbiome is the house, the microbiota is the people that live in the house.

Where do the microbes in my gut come from?

We are born with intestines relatively free of microbes. However, we are exposed to microbes that slowly build up our intestinal microbiota during and after delivery. Starting from the microbial population in the vaginal canal, our guts are colonised by microbes that shape our microbiota.² Some other factors that play a part in the development of our intestinal microbiota include: 

• our diet as infants into adulthood
• our immediate environment
• stress, and 
• our use of antibiotics

It is important to note that everyone has a unique network of microbes that make up their microbiota. There are major variations in the gut microbiome from infancy up to 3 years of age, where the microbiota becomes similar to the adult gut microbiota.³

How do the microbes in my gut help me?

The gut microbiota has been investigated extensively for their role in health and disease. Studies have shown that the human gut microbiota is involved in biological processes like nutrient extraction, immunity, and homeostasis through several mechanisms.⁴

Energy and nutrient extraction

The gut microbiota possesses a lot more genes than humans. These provide them with unique enzymes that assist us in breaking down food through processes that we can either not carry out at all or do so in a limited capacity.

They also manufacture important molecules like vitamins, amino acids, and lipids that our body needs to function.² This explains their valuable role in recovering energy, especially as the breakdown of carbohydrates is a major source of energy in the colon.

Immunity

The bacteria that make up the human gut microbiota help to regulate and develop our immune system in two major ways. First, just by existing in their millions and attaching to the host cells, they limit the number of attachment sites available for pathogens (disease-causing bacteria) to attach and grow.

They also limit the resources available, making it hard for them to survive. Another way the gut microbiota contributes to our immune system is in the production of substances called bacteriocins which are a type of antimicrobials that prevent the growth of their competitors.²

Homeostasis

The gut communicates with the brain and vice versa to maintain internal balance and stability. This communication happens through hormones secreted by the microbiota and neurotransmitters lining the gut connected to the brain.

The brain communicates with the gut and regulates functions like peristalsis (food movement through the gut), gastrointestinal secretions, etc.¹ The gut microbiome also communicates with the brain, affecting mood, cognition, and behaviour.⁵

On the flip side, when there is a disruption in the balance of the gut microbiome, studies have linked this with gastrointestinal conditions like irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and diseases like obesity and type 2 diabetes.²

How is my gut connected to my brain?

Ever heard of the gut-brain axis? It’s a communication network that links your gut and brain. Scientists refer to it as the ‘enteric nervous system’ because it comprises two layers of over 100 million nerve cells that line the gut. They communicate through hormones and neurotransmitters to regulate digestion, modulate the immune system, facilitate metabolism, and regulate your mood and cognition. 

Studies show that a significant amount of people with bowel disorders develop anxiety and depression and this is the reason that people with bowel disorders may sometimes be placed on antidepressants.⁶

Stress and its effect on your gut

Stress is a state of mental or emotional tension that affects the mind and body. Stress can manifest mentally with signs like anxiety, irritability, and lack of interest. Physical signs of stress include panic attacks, difficulty breathing, and indigestion.⁷

Previously, scientists assumed that mental conditions like anxiety and depression often related to stress contributed to disorders of the GI tract, however, recent studies have found that irritation in the gut may send signals to the brain that trigger mood changes.⁶

Some common GI symptoms due to stress are diarrhoea, lower abdominal pain, heartburn, constipation, etc. Stress actively alters gut-brain interactions that can have either short-term or long-term effects and result in a range of gastrointestinal disorders.

Some effects of stress on the gut include:⁸

• Imbalance of the intestinal microbiota (dysbiosis)
• Reduced generative capacity of the gut mucus layer
• Holes or cracks in the wall of the gut leading to increased permeability
• Exaggerated pain coming from the gut which makes you more sensitive 
• Increased contractions of the gut muscles leading to symptoms like diarrhoea and cramping
• Decreased or increased levels of secretions in the gut leading to diarrhoea or damage to the lining of the gut

Stress-related gastrointestinal disorders 

The interconnectivity of our mind and our gut is a reason that some digestive disorders can be triggered or influenced by stress. Stress may not be the reason you have a peptic ulcer, but it can be the reason the ulcer is getting worse. Let’s look at some common gastrointestinal disorders and how stress influences them.

Irritable bowel syndrome (IBS)

IBS is an intestinal disorder characterised by abdominal pain and changes in the frequency of bowel movement and stool consistency. It is a stress-sensitive disorder that is known to be influenced by an imbalance of the gut microbiome.⁹ Stress increases intestinal and gastric sensitivity, which directly affects bowel movement.

Stress-induced gastritis

Gastritis is an irritation of the stomach wall that causes inflammation. It can be caused by several factors like excessive alcohol, medication, coffee, etc. Stress can trigger gastritis when anxiety levels are high, causing an increase in the production of gastric juices while simultaneously reducing the protective mucus layer of the stomach.¹⁰ 

Inflammatory bowel diseases (IBD)

IBD is a term used to describe chronic diseases of the gastrointestinal tract where all or one part of the gut from the mouth to the anus is inflamed. It is an overreaction of the immune system to the gut microbiota and is not caused by a single factor, but instead by a cocktail of genetic predisposition, imbalance of gut microbiota, and environmental risk.¹¹ Stress contributes to IBD by altering gastric secretions and disrupting the intestinal barrier.¹²

How to support your gut microbiome when stressed

Now that you understand the effect that stress has on your gut, you might be looking for tips on what to do to handle stress better and promote gut health. You can either provide dietary support or mental support. Here is a guide on how to do that:

Dietary support

Maintaining a gut-friendly diet supports a thriving microbiota community which helps digestive health especially when stressed. A gut-friendly diet includes;¹³

• Protein:
  • They provide amino acids that help regulate our mood and reduce the effect of stress on our gut
  • Protein-rich food includes: chicken, turkey, lentils, beans, etc
• Prebiotics:
  • These are foods high in fibre that serve as food for the gut microbiota. The gut microbiota utilise these foods and carry out activities that help reduce inflammation in the gut 
  • Reduced inflammation reduces the effect of stress on our gut
  • Food containing prebiotics include bananas, almonds, soy, cabbage, etc
• Probiotics:
  • Live organisms that contribute to the growth of gut microbiota and digestive health 
  • They are found in yoghurt and other fermented foods 
  • They help regulate and correct dysbiosis, regulate mood, and maintain gastric secretion levels therefore minimising the effect of stress on the gut

Stress management/mental support

As we have already established the link between the mind and the gut, stress-induced gut disorders can be better managed and prevented when treatment also applies to the mind. Proper stress management helps tackle these disorders from the root.

• Exercise: 
  • Choosing a physical activity that you love doing helps to increase the production of chemicals that improve our mood and reduce stress hormones that contribute to the production of hormones linked with depression and anxiety¹⁴
• Rest/sleep: 
  • Sleep deficiency leads to increasing frustration and irritability, which increases stress levels 
  • Adequate sleep and rest significantly reduce stress and its effect on the body
• Relaxation therapy: 
  • It involves techniques in psychotherapy that help deal with extreme levels of stress
  • Techniques like restful music, and muscle relaxation have been effective in people with gastrointestinal disorders¹⁵

Summary

The twisting feeling in your stomach when you’re under intense pressure isn’t just a metaphor, it’s your brain communicating with your gut. Stress, anxiety, and depression symptoms don’t just stop at the mind, your gut takes a hit too. That’s why it’s important to maintain a healthy gut even when stressed to prevent these symptoms from having a long-term effect on your digestive system. 

A healthy gut is greatly regulated by a healthy microbiota which is determined by a series of factors. Therefore, it is important to take extra care of yourself when stressed by eating right, participating in regular exercise, and having adequate rest.