Science magazines on television, free advice in pharmacies and, of course, on the internet, especially on social media: hardly any other health topic is currently receiving as much attention from the general public as the gut. But why?

What scientists have known for years is now becoming increasingly apparent to the average consumer: our digestive organ is responsible for much more than just breaking down food. It also plays a key role in our well-being.

In this context, there is a growing number of articles online about promising intestinal cleansing, colonic irrigation or even detoxification programmes. The range of corresponding products on the market is large.

But what exactly is an intestinal cleanse? And can the manufacturers' preparations, some of which are complex and designed to last several weeks, really deliver what they promise?

A term that anyone interested in intestinal cleansing is bound to come across is the so-called microbiome. This refers to the community of microorganisms living in the intestine. This ecosystem is unique to each individual – like a fingerprint. The microbiome uses the mucus layer produced by the intestinal epithelium as a breeding ground, but at the same time it also forms a kind of protective barrier against pathogens.

According to studies, symptoms with mysterious causes such as frequent fatigue, digestive or skin problems, a weak immune system or even weight problems can be related to a disturbance in this very microbiome. The gut microbiome can therefore be described as the foundation of our health.

However, even the most stable foundation can be affected over time. Various factors such as stress, an unbalanced diet and medication can affect not only the microbiome itself, but also the underlying layers of the intestinal wall¹. Experts refer to this type of imbalance in the gut as dysbiosis. It limits the diversity and number of "good" bacteria, allowing "bad" bacteria to gain the upper hand.

Studies show that such an altered microbiome can have a negative effect on the intestinal mucosa – and vice versa². Intestinal cleansings are therefore generally designed to restore the balance of the microbiome while supporting the intestinal mucosa in order to ensure normal interaction between these two layers of the intestinal wall.

As the topic of intestinal health and the many connections between the intestine and our well-being are becoming increasingly apparent to the public, there are now numerous tips available online on how to restore the function and security of our "foundation of health". The most frequently mentioned remedy of choice is the intestinal cleansing mentioned earlier.

The methods described online form a veritable sea of information, making it almost impossible for people who want to cleanse their intestines to keep track of everything and find reliable advice.

To make matters worse, the market has been flooded in recent years with products that sometimes make big promises. These are mostly probiotic products, i.e. preparations containing live bacteria that are supposed to enable intestinal cleansing with comparatively little effort. They are available in all shapes, colours – and, of course, price ranges.

A vivid comparison can be used to explain the principle behind an intestinal cleansing. Like a wildflower meadow teeming with different plants, herbs, insects and animals, every human being's microbiome is a unique mixture of bacteria that exist in a delicate state of equilibrium.

This harmonious interaction is subject to natural fluctuations within certain limits throughout our lives. Similar to a flower meadow throughout the changing seasons, the microbiome also undergoes completely normal changes.

However, persistent negative influences, such as stress, an unhealthy diet or even the use of medication, can permanently disrupt this ecosystem. The landscape is virtually barren. Probiotic preparations are then used to introduce as many new seedlings as possible in the form of living bacterial cultures, so that they can settle there and "replenish" the microbiome.

In short: On the one hand, specific intestinal bacteria (known as probiotics) should be administered in a targeted manner and in high doses, thereby restoring the intestinal microbiome to its equilibrium and optimally supporting the intestine in fulfilling its tasks. On the other hand, ideally, different ingredients should also address the intestinal mucosa – for all-round well-being.

This sounds very plausible at first glance, but is there really any truth to it?

As with any hype, numerous myths and claims quickly arose about the probiotics contained in intestinal cleansers, making it even more difficult to choose the right product.

We take a closer look at the most widespread myths:

The various intestinal cleansings we examined differed greatly from one another. This was particularly evident, for example, in the number and selection of bacterial strains examined, as well as in the dosage and packaging. All these criteria ultimately determine the quality of a product.

In fact, some bacteria, especially bifidobacteria and lactic acid bacteria, are resistant to stomach acid.

Although this may sound surprising at first, it is logical – after all, the bacteria already present in our intestines, which we have ingested through our diet, have also travelled this path and arrived alive. Therefore, enteric-coated capsules containing bacteria that occur naturally in the gut are unnecessary for such products.

There are certainly foods with probiotic properties; for example, yoghurt, sauerkraut and the currently popular Korean kimchi contain lactic acid bacteria. However, the diversity and variety of bacteria in food is quite low. In addition, many products are pasteurised, which kills bacteria (both good and bad).

Good preparations, on the other hand, contain at least 20 billion colony-forming units (CFU) per capsule.

Numerous studies have proven the connection between the microbiome and health.

A team of researchers from Chicago showed that mice with weakened immune systems had a much higher chance of survival after contact with pathogens when they were given the microbiome, i.e. the microorganisms, of healthy mice³. Similar studies have also been conducted on topics such as allergies⁴ and fatigue⁵.

The idea behind an intestinal cleansing is to support the intestine in the long term.

Considering the extraordinary number of bacteria in our intestines, it is clear that significant results cannot be achieved overnight. Although some people notice slight changes after the first week (especially in terms of digestion), micronutrient experts such as Martin Gschwender recommend consumption over a period of at least three months.