main health benefits of probiotics

What are Probiotics – How to Improve your Gut Microbiota

The gut microbiota plays an important role in our health. Dysbiosis of your gut microbiota can, thus, affect your metabolism. Probiotics, however, can help you improve the composition of your gut microbiota. This will prevent gut dysbiosis and all the health consequences associated with it.

In this post we talk about probiotics and gut microbiota. A brief introduction to the gut microbiota, to then discuss everything you are wondering about probiotics.

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What’s the Gut Microbiota?

The gut microbiota, also known as gut microbiome, is the community of microorganisms inhabiting your digestive tract (source). These microorganisms have established, through evolution, a symbiotic relationship with the host (humans). This is, both the host (human), and parasite (microorganism), benefit from each other (study)

The gut microbiota is highly linked to your health status. With more bacterial cells than human cells (source),the gut microbiota has a big word on the status of your metabolism and many other different functions.

Factors Modulating Gut Microbiota

Development of the Gut Microbiota

The gut microbiota is unique to each of us. The composition and richness of the gut microbiota is part of our identity (study).

From early stages of life, we are continuously developing and shaping the gut microbiota. Since the very first moment we are born, microorganisms enter our gut and start creating their environment (study). Mode of delivery, breast feeding, interactions with the environment, diet, physical exercise,... all can affect the composition of our gut microbiota (study)

Health Benefits of the Gut Microbiota

The gut microbiota plays a big role in our health and disease. Considered by many as an "essential organ", the gut microbiota is key for our survival and evolution.

Your gut microbiota can strengthen your intestinal barrier (study). It will prevent pathogens entering in our system. Morover, the gut microbiota is able to modulate our inmune system by various mechanisms (study).

But that's not all. In fact, the most important benefit of gut microbiota in our health is its metabolic function. Microorganisms are able to metabolize non-digestible fibres and other compounds to convert them in compounds that we can use for our metabolism (study)

gut microbiota in health and disease

What are Probiotics?

Probiotics are live microbial supplements which beneficially affect the host by improving microbial balance (source)

In other words, probiotics are supplements containing living microorganisms (source). Although all microbial species would be considered probiotics, we only consider probiotics the microorganisms known to be "benefitial" for our gut.

The market of probiotics has increased tremendously in the past years (source). The more we know about the gut microbiota, the more interested we are on improving it. And probiotics can help us on that (study)


Most probiotics are bacteria, but there are also some yeast and funghi strains available. The most common probiotics bacteria are Lactobacillus and Bifidobacterium (study). The interactions of these strains with the gut microbiome are very well understood. In fact, the health of your gut microbiota largely depends on the amount of these two microbial families (study).

But probiotics don't only cover supplements. Some foods are also considered probiotics. Fermented foods contain living microorganisms (study). These microorganisms are reponsible of the fermentation, and are kept alive in the food matrix. Fermented foods include kimchi, sauerkraut, kefir, yogurt, or tempeh.

What Microorganisms are Considered Probiotics?

Not all microorganisms can be used as probiotics. In order to exert benefits in the gut microbiota, the microorganism must be able to tolerate bile acids and low pH, adhere to the intestinal mucosa, and show antimicrobial activity towards pathogens (study).

So, in other words, the microorganism needs to survive the journey to the intestine. Once in the intestine, it needs to adhere to the intestinal barrier, and kill the pathogens. If the biological properties allow it to do that, it's welcome to the elite of probiotics 🙂

For the sake of simplicity, below there's a table with the main probiotic strains used nowadays.

most popular probiotic microorganisms

Health Benefits of Probiotics

Probiotics, either coming from fermented foods or supplements, bring some benefits both to human and gut microbiota's health. In the next 5min, we'll cover the main benefits of taking probiotics. 

Probiotics Help Balance the Gut Microbiota

The gut microbiota is affected by a lot of factors. Diet, lifestyle, stress, physical activity,... (read more). Sudden changes in your life can disturb your gut microbiota, also called gut dysbiosis.

Probiotics, however, can help you restore the composition of your gut microbiota (study). They introduce benefitial functions to the gut microbiota. That can help preventing diseases related to gut dysbiosis, or simply improve the health of your gut microbiota.

Probiotics Modulate Intestinal Inmune System

Gut dysbiosis leads to chronic inflammation state (study). If prolonged on time, it can derive on more serious diseases, such as Chron's disease, or IBD (study)

Introducing probiotic microorganisms can help you prevent that and modulate the intestinal inmune system. Benefitial bacteria produce metabolites such as SCFAs, or vitamins. These compounds interact with the inmune system, inhibiting the inflammatory response (study)

probiotics modulate intestinal inmune system

Probiotics May Help You Lose Weight

Probiotics can help you lose weight through different mechanisms (study).

Although not all probiotics aim to lose weight, there are some microorganisms with special mechanisms by which it could favour weight loss.

Some probiotics prevent the absorption of dietary fats in the intestine. These fats will be excreted, instead of stored in our organism (study).

Studies done in humans show how taking probiotics could lead to higher weightloss when compared to the group that didn't take probiotics (study)

Other studies focus on the effect of the metabolites produced by the probiotics. Compounds such as SCFAs, or CLA could have an impact on regulating the appetite, lowering the size of adipocytes, or increasing fatty acid oxidation (study).

probiotics help lose weight

However, keep in mind that this is just growing evidence, and the effect may not even be noticeable. If you want to lose weight, start by following the correct nutrition and physical exercise!

Probiotics Improve your Mental Health

The gut-brain axis plays a central role in your mood and mental health (study). Following the chain, the gut microbiota modulates the gut's health. Thus, the gut microbiota has a word to say in your mental health as well (study).

Probiotics can restore your gut microbiota, and therefore have a potential role in the treatment and prevention of anxiety and depression (study).

The gut microbiota is also responsible of producing neurochemicals and neurotransmitters (study). As probiotics can restore your gut microbiota, they can indirectly increase the production of these compounds.


The gut microbiota is a central piece in our health. It provides inmunity, helps our metabolism, and it's essential for our survival.

Gut dysbiosis is prevalent nowadays. Probiotics, which are living microorganisms, are used to improve our gut microbiota. In this post, we reviewed the main health benefits of probiotics.

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