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What Are Probiotics And Do I Need A Probiotic Supplement?

What Are Probiotics And Do I Need A Probiotic Supplement?

The more we know about gut bacteria and their role in our health and metabolism, the more we want our microbiome to stay balanced.

The right way to support gut bacteria composition is to eat a variety of foods, but some companies also offer an easy way out: probiotic supplements. Let's see how they work.

Firstly, what are probiotics?

Probiotics are foods or supplements that contain live bacteria, potentially beneficial to human health. The most popular probiotics are certain strains of Lactobacilli and Bifidobacteria, Saccharomyces boulardii and Bacillus coagulans, but there are also less famous probiotic strains of E.coli and E. faecium.

Some foods, such as fermented milk products (natural yoghurt, kefir, cheese), kombucha, sauerkraut, miso, kimchi and pickles are made with starter strains, belonging to Lactobacillus or Streptococcus genera. Some of these strains might possess probiotic functions as well. Nowadays some fermented products are intentionally made enriched with probiotic strains.

Probiotics supplements can contain specific strains of some bacteria or a blend of different microbe species.

What do probiotics do?

It is claimed that probiotics help to restore the balance of gut flora after taking antibiotics, treat diarrhoea and irritated bowel syndrome and improve the immune system. However, there’s no bullet-proof evidence of these effects. Neither the European Food Safety Authority nor the US Food and Drug Administration have approved any probiotics as suggested medical intervention.

First of all, we are not sure how they actually work. The idea is quite simple: you eat probiotics, and good bacteria arrive in your gut to live there happily ever after. In practice, however, this process is not so straightforward. It is not yet clear how bacteria survive in the stomach with its very aggressive acidic environment. Furthermore, the evidence of exogenic (from outside) bacteria colonisation of the gut flora remains contradictory.

In 2018, a group of Israeli researchers published a study about the peculiarities of taking probiotics for humans. It shows that a successful gut colonization by probiotics depends on the host’s gut bacteria composition, and therefore, there is no one-fits-all probiotic pill.
Recent studies show that different probiotics act differently in each microbiome.

Depending on one’s microbiome profile, some probiotics may have a transitory effect, e.g. they do not settle in the intestines for life, but just pass through and show up in the stool sample after being taken. A month after finishing the probiotics course, the microbiome composition doesn’t show a significant difference from its baseline. This is called probiotic resistance.

Meanwhile, the impact of taking probiotic was maintained even after a month in some cases. These people were called probiotic permissive. The study shows that the way one’s microbiome would react to taking certain probiotics can be predicted based on one’s microbiome composition.

Does it mean probiotics are useless?

It depends. Default over-the-counter probiotic supplements can’t guarantee the amount of bacteria and their effect on the microbiome. In other words, it's not an undisputed recommendation to take probiotics supplements, even though sometimes they can offer relief after antibiotics and gut inflammation diseases.

However, if you take the gut bacteria test and find a pack of probiotics specifically tailored for you, it may be more profitable for your body.

If you don’t have access to a personalised probiotic, try eating probiotics in the form of food. If they come with other nutrients and possibly fibre – this will help your gut flora balance anyway. The exception is yoghurt. Even though for decades they have been promoted as the best remedy for gut health, most yoghurts don’t contain any probiotics at all (bacteria cannot outlive pasteurisation). Instead of beneficial bacteria, many yoghurts contain added sugars and can't be recommended as a part of healthy eating. If you like yoghurt, try looking for a plain one.

If not probiotics, what should I take?

Instead of probiotics, you can look at prebiotics, which are types of dietary fibre that act as food for beneficial gut bacteria. Prebiotics supports the number of 'good bacteria' in the microbiome. You can find them in grains, fruits, veggies and legumes.


1. Probiotics are products and supplements that contain live bacteria.
2. Prebiotics are dietary fibres that bacteria can eat.
3. You may find probiotics in fermented foods, such as kefir, kombucha, miso, kimchi.
4. You will find prebiotics in fruit, vegetables, whole grains and legumes.
5. The effect of probiotics depends on one’s microbiome profile. To enhance the effectiveness, any probiotic supplement composition should be personalised based on the results of a gut bacteria test.

Order an Atlas Microbiome Test to know your gut bacteria composition
and receive personal food recommendations.

Ann Day

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