Gut health and the microbiome: what really helps the gut

The gut is far more than a digestive organ: it is home to trillions of microorganisms, influences the immune system, the metabolism and even wellbeing. No wonder that "gut health" and "the microbiome" have become big health topics — accompanied by many promises and just as many myths. This guide explains factually what really does good.

1. What is the microbiome?

The microbiome (often also called the "gut flora") is the totality of the microorganisms that colonize our gut — above all bacteria, but also fungi and viruses. These are trillions of microbes from hundreds of different species, which together form a complex "ecosystem".^¹

This ecosystem is individual in every person — almost like a fingerprint. It develops from birth and is shaped by many factors: diet, lifestyle, medications, environment and genetics. A varied, balanced microbiome is regarded as a sign of healthy gut flora, while impoverished gut flora or gut flora that is out of balance (a so-called "dysbiosis") is associated with various complaints.

2. What jobs does the gut flora have?

The microbiome takes on astonishingly many jobs — it is far more than a passive lodger:

• Digestion: the gut bacteria help to break down food components (above all fibre) that the body could otherwise not use — and in doing so form valuable substances such as short-chain fatty acids
• The immune system: a large part of the immune system sits in the gut; the microbiome "trains" and regulates the defences
• A protective barrier: healthy gut flora makes it harder for disease-causing germs to spread
• Vitamin formation: certain bacteria produce vitamins (e.g. some B vitamins, vitamin K)
• Metabolism: the microbiome influences how we use food and gain energy
• Communication with the brain: via the gut-brain axis (its own chapter)

This variety of functions explains why healthy gut flora is so important for general wellbeing — and why disturbances can show themselves in quite different ways.

3. The gut-brain axis: a gut feeling with a system

One of the most exciting fields of research. The gut and the brain are in constant connection via the gut-brain axis — through nerve pathways (above all the vagus nerve), hormones and messenger substances. The gut is therefore sometimes called the "second brain", because it has its own dense nervous system.^¹

• Bidirectional communication: the brain influences the gut (e.g. "stress hits the stomach") — and the gut sends signals to the brain
• Messenger substances: a large part of the messenger substance serotonin is formed in the gut; the microbiome is involved in producing various substances
• Wellbeing: research points to connections between the gut flora and mood/stress processing — but much is not yet conclusively clarified

The "gut feeling" and the phenomenon that stress and emotions hit digestion (or conversely that gut problems influence mood) therefore have a real biological basis. In irritable bowel syndrome, this gut-brain axis plays an important role.

4. What harms the microbiome?

Some factors can impair the diversity and balance of the gut flora:

• A one-sided, fibre-poor diet: a lot of sugar, highly processed foods and little plant-based food impoverish the gut flora
• Antibiotics: they act not only against disease-causing but also against beneficial bacteria (its own chapter)
• Chronic stress: influences digestion and the microbiome via the gut-brain axis
• A lack of exercise and poor sleep
• Smoking and excessive alcohol
• Certain other medications (beyond antibiotics)

5. Antibiotics and the gut flora

An especially important topic. Antibiotics are often necessary and can save lives — but they do not act in a targeted way only against the disease-causing bacteria, but also against many beneficial gut bacteria:^²

• A temporary impoverishment of the gut flora during and after an antibiotic therapy
• Antibiotic-associated diarrhoea: a common consequence, because the balance in the gut is disturbed
• Recovery: the gut flora recovers in most people after some time — but that can take weeks to months
• A rare severe complication: an overgrowth with the bacterium Clostridioides difficile can cause severe diarrhoea (to be clarified medically)

6. What really helps the gut: diet

Diet is by far the most important lever for healthy gut flora — more important than most expensive "gut products". What is decisive is a varied, plant-based and fibre-rich diet:

• Variety: the more varied the plant-based diet, the more diverse the gut flora — many different vegetables, fruit, legumes, whole grains, nuts and seeds
• Fibre: the most important "food" for the good gut bacteria (its own chapter)
• Fermented foods: yoghurt, kefir, sauerkraut, kimchi contain live bacteria and can support the gut flora
• Less highly processed food: reduce sugar, white flour and highly processed products
• Drink enough: important for digestion and against constipation
• Plant variety over expensive preparations: a good diet beats most dietary supplements

7. Fibre — the most important gut food

Fibre deserves its own chapter, because it is the central factor for healthy gut flora. These are indigestible plant components that are used by the gut bacteria in the large intestine:

• Food for the good bacteria: from fibre, the gut bacteria form valuable short-chain fatty acids, which nourish the gut lining and have an anti-inflammatory effect
• Good sources: whole grain products, legumes (lentils, beans, chickpeas), vegetables, fruit, nuts, seeds (e.g. flaxseed/psyllium)
• Digestion and bowel movements: fibre promotes regular digestion and prevents constipation
• Increase slowly: anyone who is used to little fibre should increase the amount step by step and drink enough — otherwise bloating can occur

Most people eat too little fibre. Increasing it is one of the most effective and best-proven measures for gut health — cheaper and often more effective than special preparations.

8. Probiotics and prebiotics: what do they do?

Two much-advertised terms — here an honest assessment:

Probiotics

Probiotics are live bacteria (e.g. in certain yoghurts, kefir or as a preparation) that are meant to support the gut flora. The evidence is mixed: for certain, clearly defined situations (e.g. to prevent antibiotic-associated diarrhoea, with certain irritable-bowel complaints) there are indications of a benefit — though it depends on the specific bacterial strain. A blanket benefit for every healthy person, by contrast, is not proven.

Prebiotics

Prebiotics are indigestible fibres that serve as food for the good gut bacteria (e.g. inulin, certain fibres in onions, leeks, chicory, legumes). They promote the growth of beneficial bacteria — most simply and cheaply through a fibre-rich diet.

9. Exercise, sleep and stress

Gut health does not only depend on diet — the whole lifestyle plays a part:

• Exercise: regular physical activity has a favourable effect on the gut flora and digestion and promotes regular bowel activity
• Sleep: sufficient, regular sleep also supports digestion via the biorhythm; chronic lack of sleep has an unfavourable effect
• Stress management: via the gut-brain axis, chronic stress has a direct effect on the gut — relaxation techniques, exercise and breaks help
• Routine: regular meals and a regulated daily routine do digestion good

Especially with stress-related or functional gut complaints (such as with irritable bowel), stress management and exercise are often just as important as diet. The gut reacts sensitively to the whole lifestyle.

10. Myths around gut health

The topic of the gut is full of promises — a fact-check of some widespread myths:

• "Colon cleansing/detox detoxifies the body": the body detoxifies itself via the liver and kidneys; elaborate "colon cleanses" or "detox programmes" are usually unnecessary and sometimes even harmful.
• "Everyone needs probiotics": not proven — for healthy people a good diet is usually enough.
• "A microbiome test tells me what to eat": commercial microbiome tests are not yet scientifically mature and rarely deliver concrete, reliable recommendations.
• "Gluten-free/lactose-free is healthier": only sensible with a proven intolerance — for others no general advantage.
• "The gut is to blame for everything": the gut is important, but not responsible for every complaint — beware of oversimplification.

A healthy scepticism towards expensive "gut products" and grandiose promises is sensible. The most effective measures are usually the simple and cheap ones: a good diet, exercise, stress management.

11. Irritable bowel, Crohn's and co.: when the gut is ill

Gut complaints are common — most are harmless and temporary. But there are also more serious gut diseases that have to be treated medically. A brief overview:

Irritable bowel syndrome (IBS)

Irritable bowel syndrome is a common functional disorder with abdominal pain, bloating and changed bowel movements (diarrhoea and/or constipation) — without a detectable organic cause. The gut-brain axis and the microbiome play a role. It is a burden, but not dangerous; it is treated with diet, stress management and targeted medications.

Inflammatory bowel disease (Crohn's disease, ulcerative colitis)

Crohn's disease and ulcerative colitis are genuine chronic inflammations of the gut (an autoimmune process) — with diarrhoea (sometimes bloody), abdominal pain, weight loss and flare-ups. They require specialist treatment (e.g. with anti-inflammatory medications such as budesonide capsules or other active ingredients).

Others

Food intolerances (e.g. lactose, fructose intolerance), coeliac disease (gluten intolerance) and infections can also cause gut complaints. The distinction belongs in medical hands.

12. When you should see a doctor about gut complaints

Most gut complaints are harmless. But certain warning signs should always be clarified medically:

• Blood in the stool or black, tarry stool
• Unintended weight loss
• Persistent abdominal pain or a clear, lasting change in bowel habits
• Persistent or bloody diarrhoea
• Night-time complaints that wake you up
• Fever together with gut complaints
• Anaemia or iron deficiency without a clear cause
• Bowel cancer in the family — take up screening
• Complaints that last longer than a few weeks

13. How brite helps you with gut health

Especially with gut complaints, a good symptom diary and a complete medication overview make a big difference — they help to recognize patterns and to have a concrete conversation at the next doctor's appointment:

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