Gut & Microbiome: Probiotics, Fibre & Nutrition

A note before we begin: For probiotics and many gut-related ingredients, no health claims are currently authorised in the EU. We therefore describe them neutrally and without promising any effects. If digestive complaints persist, a medical assessment is advisable.

Few nutrition topics are discussed as intensely as the gut and its microbiome. "Gut cleanse", "good bacteria", "rebuilding after antibiotics" – many promises circulate around probiotics, and it is hard to separate substance from marketing. This guide stays factual and puts things in context: what actually is the microbiome? What distinguishes probiotics from prebiotics? What role do nutrition and fibre play – and what should you look for in culture complexes?

The key points at a glance

• The microbiome is the entirety of the microorganisms in the gut – individual to each person.
• Probiotics are live cultures, prebiotics are their "food" (certain types of fibre).
• The foundation is nutrition: plenty of plant variety, fibre and fermented foods.
• For probiotics, no health claims are authorised in the EU – we describe them neutrally.
• With culture complexes, what counts is strain diversity, a clearly stated cell count (CFU) and processing that delivers the cultures all the way to the gut.

The microbiome – the world inside the gut

Trillions of microorganisms live in the gut – above all bacteria, but also fungi and viruses. This community is called the microbiome. You can picture it as a highly complex internal ecosystem that takes part in digestion, breaks down fibre and forms metabolic products in the process. The microbiome is as individual as a fingerprint in every person and is shaped by, among other things, diet, lifestyle, age and environment.

What is fascinating is how actively this field is currently being researched: science is investigating how the composition of the microbiome relates to various aspects of well-being and what role the gut-brain axis plays – the connection between the digestive system and the nervous system. Much of this is promising, but not yet conclusively established. Here we deliberately stick to what can be described soundly, rather than jumping to premature conclusions.

Probiotics & prebiotics – the difference

The two terms sound similar but mean opposite things:

One approach brings cultures with it, the other supports those already present. A vivid image: probiotics are like new plants you set into a bed, prebiotics like the fertiliser that strengthens the existing growth. The two can be combined – this is then called synbiotics. How the two approaches differ and complement each other is explored in more depth in Probiotics vs. Prebiotics. On the best-known prebiotic in particular – inulin, which often comes from the chicory root and is added to many culture complexes – Inulin: Prebiotics Explained Clearly is worth a read, and on soluble fibre Psyllium Husk: Effects & Use.

Fermentation – an ancient principle

The idea of taking in live cultures through food is thousands of years old. Long before anyone coined the word "probiotic", people around the world fermented foods – originally to preserve them. Sauerkraut in Central Europe, kimchi in Korea, kefir from the Caucasus, miso and natto in Japan, yoghurt in the Middle East: all of these traditions rely on microorganisms converting sugar and starch into acids. The fact that these foods contain natural cultures is therefore not a new wellness trend, but a very old culinary principle that is being rediscovered today under a new name. Anyone who works fermented foods into their daily routine is drawing on this long tradition.

Nutrition is the foundation – fibre and fermented foods

Before thinking about supplements, it is worth looking at your plate, because much can be covered through diet. Two building blocks are particularly relevant:

• Fermented foods such as yoghurt, kefir, sauerkraut, kimchi or miso contain natural cultures.
• Fibre-rich foods such as vegetables, pulses, wholegrains and fruit provide the "food" for the gut bacteria.

Perhaps the most important lever is the variety of plant-based foods: the more colourful and varied the menu, the more different types of fibre are available to the bacteria. A frequently cited rule of thumb is to eat as many different plant-based foods per week as possible – vegetables, fruit, pulses, nuts, seeds and wholegrains all count. It is not the one "superfruit" that makes the difference, but the breadth. How to think about fibre and digestion together in everyday life is shown in Nutrients and Digestion. If you eat little in the way of vegetables, you will find practical approaches in Nutrients When You Eat Few Vegetables.

What research is investigating

Few nutrition topics are as scientifically lively right now as the microbiome. Research looks at how the composition of the gut flora differs between people and which factors shape it – from diet to exercise to sleep. One large field is the aforementioned gut-brain axis, that is, the communication between the digestive and nervous systems. The question of which individual bacterial strains play a role in which situation is also the subject of many studies – because "probiotic" is an umbrella term for very different strains that do not behave the same way. To be honest, much of this has not yet been conclusively established: research provides intriguing clues, but rarely simple if-then answers. That is precisely why we describe the topic with restraint and draw no promises of effect from it.

What does the gut good in everyday life

Besides fibre and fermented foods, there are a few unspectacular but effective habits:

• Plant variety and sufficient fibre – the foundation.
• Fewer heavily processed foods and less sugar.
• Drinking enough and chewing thoroughly – especially important with a fibre-rich diet.
• Exercise and stress management – the gut and the mind are connected via the gut-brain axis (more in Stress & Inner Calm: Magnesium & Adaptogens).

A special case is the time around taking antibiotics – what to keep in mind is explained in Supplements and Antibiotics.

Culture complexes as a supplement – what to look for?

In addition to diet, there are culture complexes with various bacterial strains. If you are interested in these, a few objective quality features can help you choose:

• Strain diversity: several different bacterial strains rather than just one.
• Clearly stated cell count (CFU): the number of colony-forming units should be shown transparently.
• Processing: a production method and, where applicable, a capsule shell that delivers the cultures all the way to the gut.
• Storage: follow the manufacturer's notes on shelf life and storage.

What matters for quality in detail is explored in Recognising Probiotic Quality. Whether a capsule or a powder is more practical is clarified in Probiotics: Capsule or Powder?. You will find products on this topic in the Gut & Digestion category.

Safety note: In cases of persistent or severe digestive complaints, immune deficiency, or during pregnancy and breastfeeding, use should be discussed with a doctor. Food supplements are not a substitute for a balanced diet.

An honest assessment: what is established and what is not

What probiotics and prebiotics are can be described factually and is uncontested: live cultures on one side, their fibre "food" on the other. Equally solid is the fact that a fibre-rich, plant-diverse diet forms the basis for a rich microbiome – this is well documented. Actively researched but not yet conclusively established are many points of detail: which strain does what in which situation, how strongly individual supplements lastingly change the microbiome, and exactly how the gut-brain axis works. Because no health claims are authorised for probiotics in the EU, we deliberately refrain from promising any effects – and stick to what can be said responsibly. If complaints persist, medical advice is the right course.

Matching products from Scheunengut

Culture complexes, fibre and further products related to digestion are gathered together in the Gut & Digestion category. Pure bacterial cultures are in our Bacterial Cultures category, and prebiotic fibre around inulin rounds out the topic. If you would like to look at the connection between nutrition and digestion more broadly, you will find guidance in Nutrients and Digestion as well as in the comparison Probiotics vs. Prebiotics. All products are laboratory-tested and made in Germany.

Frequently Asked Questions (FAQ)

What is the difference between probiotics and prebiotics?

Probiotics are supplements or foods containing live bacterial cultures (e.g. lactobacilli, bifidobacteria; yoghurt, kefir). Prebiotics are indigestible fibre such as inulin that serve as food for the existing gut bacteria. In short: probiotics bring cultures with them, prebiotics feed the ones already present. Combined, the two are called synbiotics.

Do you even need probiotics as a supplement?

The foundation is diet: plenty of plant variety, fibre and fermented foods such as yoghurt, kefir or sauerkraut cover a lot. Culture complexes can be interesting as an addition. Since no health claims are authorised for probiotics in the EU, we describe them neutrally. If complaints persist, a medical assessment is advisable.

What should you look for in a culture complex?

Useful features are a high strain diversity (several different bacterial strains), a clearly stated cell count in CFU (colony-forming units), processing that delivers the cultures all the way to the gut, as well as clear notes on shelf life and storage. Transparent labelling and laboratory testing are additional marks of quality.

What is the gut-brain axis?

The gut-brain axis describes the connection between the digestive system and the nervous system, through which the gut and the brain communicate in both directions. It is a highly active field of research: among other things, it examines how the microbiome relates to well-being and stress. Much is promising, but not yet conclusively established – so we describe it with restraint.