How to feed your gut microbes to relieve stress

The natural ecosystem present in your gut is integral to almost all aspects of your health, including your mental wellbeing. That’s right, your gut and brain have a special, unique relationship and are able to communicate with each other, so they each know how the other is feeling. If your gut is upset, it’s likely your brain will be too. 

Your colon is home to trillions of bacteria, most of which are living in harmony with you, some are even working hard to keep you healthy by producing magical metabolites that support your wellbeing. It’s cool stuff, right?

But imagine it’s the night before a job interview or a big presentation, and you’ve got butterflies in your stomach. Well, that’s a classic example of what stress can do to your gut. But what about if you could eat to relieve stress? Sounds almost too good to be true, doesn’t it? But a recent study by Berding et al. (2022) investigated just that, and in this article, we uncover the results.

What is stress?

Stress affects all of us at some point in our life. Some may only experience it temporarily, but for others it may be more long-term. Recently, the entire world has been through a stressful event; the COVID-19 pandemic which was responsible for increasing the stress, depression and anxiety levels in many of us. The current prevalence statistics for stress are varied with some studies showing 50% of people are under some form of psychological distress[i]. In the US it’s estimated that just over three quarters of people are experiencing stress[ii], while in the UK the same figure feels so stressed, they are unable to cope[iii].

Whatever the correct statistics are, these figures are scarily high which is why we all need to find ways to help relieve this feeling. Especially as today the top five causes of death in the world are stress-related[iv]!

Stress and the gut: What’s your microbiome got to do with it?

Your gut and brain have a unique bi-directional communication pathway[v], called the gut-brain axis. You may have heard your gut being called the body’s ‘second brain’. That’s because it houses an important network called the enteric nervous system. It’s this complex web of nerve cells that are responsible for all of the digestive processes, like muscle contractions, releasing digestive enzymes and even managing blood flow through the gastrointestinal (GI) tract. But it’s also responsible for regulating the immune system within your gut which is home to 70% of your immune defences. So, it plays a major part in protecting you from pathogens and illness.

Even though your brain may get a lot of attention, it has its own ‘telephone line’ to your gut. This two-way communication pathway means the cognitive and emotional powerhouses in your brain are linked to your colonic functions. You can kind of see why, when you’re nervous you may have a sudden urge to need the toilet or experience irritable bowel syndrome-like symptoms.

Over the years, increasing research has shown that mood disorders like anxiety, depression and even autism are associated with a disrupted or imbalanced gut[vi]. So, it should be little surprise that stress can cause a whole variety of GI symptoms.

How does stress affect your gut

Stress can cause an array of gastro issues including bloating, diarrhoea, cramping, and loss of appetite. Many of us hate things like public speaking or sitting exams, and in the past, when you have been faced with something that has made you feel anxious, you probably suffered some sort of digestive symptom, if not a few.

But why is that?

When you are faced with a stressful situation, the sympathetic nervous system, the one that’s responsible for our ‘fight or flight’ response, is activated. And once the ‘danger’ has passed, the parasympathetic nervous system effectively calms you down. Both of these systems, however, interact with the enteric nervous system, the one in your gut that’s responsible for the regulation of digestion.

So, when you hear the gut being referred to as your body’s “second brain”, what is in fact being mentioned is the enteric nervous system. That’s because it relies on the same nerve cells and neurotransmitters as those in the central nervous system. And that’s why when you’re stressed, your digestion can take a hit. For example, your digestion may slow down, causing abdominal cramps, or feeling like you need to rush for the loo[vii].

The reason for this is the stressor increases the production of the hormone, cortisol, which instructs the body that it’s under stress. This causes a cascade of signals to travel between the gut-brain axis, telling the gut to direct energy to elsewhere in the body, like your legs, if you need to run away from danger. Because let’s face it, if you’re in danger, digestion probably isn’t going to help you. So, blood flow is diverted to the places where it may be needed the most, like your limbs – hence the cramping and diarrhoea.

It’s important to remember that short-term stress is natural and unlikely to cause you long-term harm, it can even be a good thing in some situations. But long-term or prolonged stress can increase your risk of chronic disease. That’s why it’s important to look for ways to relieve stress or even prevent it, if possible.

Can diet relieve the symptoms of stress?

We’re all well aware that we need to eat a healthy and varied diet to help support our microbial pals – it’s the best way to a balanced microbiome. But could diet really attenuate our stress levels?

A study by Berding et al. (2022) investigated just that. The effect of diet on the composition of the human gut microbiome and the role of diet supporting mental health has gathered lots of traction in recent years, but there is little research into whether certain diets can have psychobiotic effects. That is pre- or probiotics that can influence the brain and induce antidepressant results[viii].

In the 2022 study, a psychobiotic diet, one which was high in prebiotic and fermented foods but low in sweets, fast food, and high-sugar drinks, was analysed to see its effect on microbial composition and function as well as mental health outcomes in healthy adults.

There were 45 participants in total, 24 were randomly assigned the psychobiotic diet and 21 to a control diet for four weeks. To analyse the results, stress, health, and diet were assessed by validated questionnaires, faecal microbiota composition was analysed through shotgun sequencing and metabolic profiling of plasma, urine and poo samples was performed.

What did the results of the study reveal?

Overall, the study showed that perceived stress scores reduced by 32% in the psychobiotic diet group. These results were dose dependent, so the more someone stuck to the diet, the greater the result (or less stressed they felt)[ix].

The researchers also noted that there was a change in the overall microbial composition of the microbiome between specific time periods, also known as volatility. However, there was no change in overall composition and function of the gut microbiota and the positive benefits appear to be short-term as there were no significant differences between the two diet groups after the intervention.

Yet, stress is a confounding factor for the development of chronic disease, so the promising results of this study mean a psychobiotic diet could one day be a potential therapy or preventive measure.

How can I increase my intake of prebiotics and fermented foods?

Prebiotic foods are those that have been proven to encourage the growth of beneficial bacteria in your gut. They come in all shapes, sizes and colours and are mostly complex carbs or fibre.

Because our bodies are ill-equipped to break them down, the bacteria residing in the colon do it for us. They have numerous benefits within the gut and beyond via their promotion of species such as Bifidobacteria, resulting in a strong gut lining, boosted immune system and a reduction in pathogens[x].

Fermented foods, on the other hand, are produced via the process of fermentation where bacteria and yeasts are responsible for breaking down sugar. These bacteria are often beneficial probiotics associated with numerous health benefits[xi].

Here are some of the foods you could try incorporating into your diet:

Human milk oligosaccharides are also a type of prebiotics that may help to relieve stress-induced gut dysmotility. A study by Farhin et al. (2018) showed that a single HMO, 2’-fucosyllactose (2’-FL) has stress reversing capabilities in the gut but it also has other benefits through its promotion of Bifidobacteriaspecies[xii].

You can help bolster your own gut microbiome with Layer Origin’s PureHMO® Prebiotic Powder where each serving contains 2000 mg of 2’-FL.

Summary

Overall, the gut and brain are intrinsically linked and disruption in either organ can have wide-ranging effects on the other. Stress is a strong example, where not only does it affect your mental health but can also have an effect on your digestive process.

Written by: Leanne Edermaniger, M.Sc. Leanne is a professional science writer who specializes in human health and enjoys writing about all things related to the gut microbiome. 

Sources

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