What are Probiotics?

The human gut is home to trillions of microorganisms, collectively known as the microbiome. Among these are probiotics - live bacteria and yeasts that play a vital role in maintaining a balanced gut environment. By supporting digestive health and crowding out harmful bacteria, probiotics contribute to overall well-being.

With approximately 70% of the immune system located in the gut, its health is closely linked to immunity, digestion, and various aspects of systemic health. Disruptions to the gut microbiome, known as ‘dysbiosis,’ can lead to digestive discomfort, lowered natural immunity, and other health conditions.

In this article we explore what are probiotics and more:

• What do probiotics do?
• What is a probiotic strain?
• Is there a difference between live cultures and probiotics?
• What’s the difference between probiotics, prebiotics, and postbiotics?
• Probiotics and health concerns
• Key takeaways

 

 

What do probiotics do?

Many people are confused about what are probiotic supplements, and what probiotics do. There are many questions about the role of probiotics in health, which we answer in this article.

Well, research confidently supports the fact that probiotics do support digestive health by producing specific enzymes¹ needed in the digestion of food and aiding the breakdown of foods substances.
Probiotics are also known to improve the absorption of vitamins & minerals into the bloodstream, and even produce B complex vitamins & vitamin K². B vitamins are vital for maintaining energy levels and brain function³, while vitamin K plays a key role in bone health⁴. In addition, ‘bad’ strains of bacteria, known as pathogens, can be crowded out by probiotics, the ‘good’ strains of bacteria, so they help to complement and support the health of the gut microbiome.

Probiotics are also thought to support immunity by stimulating the body’s natural defences, and by lining the intestines with a protective layer of friendly bacteria that bars pathogenic substances in the gut from harming the body. As two-thirds of the body's immune system is managed in the gut, it may be important to keep one's probiotic levels high.

There is mounting research to support the role of probiotics in a host of other health conditions and parts of the body - read on to find out more about how probiotics support the skin, vagina, mood, and heart health. 

Read more about what are probiotics and how they work in our articles How do probiotics work? and Benefits of probiotics

What is a probiotic strain?

It is important to point out that there are many different types of probiotics, called strains, and each one has its own special function. Research shows that different probiotic strains have different benefits and can help support different areas of health. Read more about this here: Are all probiotics the same?

But what is a probiotic strain? A strain denotes a type of bacteria - and informs us on a very specific, in-depth level (more specific, than a species, for example). Take a look at the image below to understand the context of genus, species and strain.

GENUS: A genus is a biological classification of living organisms. The term comes from the Latin genus meaning group. A genus contains one or more species. Examples of common probiotic genera include Bifidobacterium and Lactobacillus.

SPECIES: ‘Species’ refers to a type of microorganism existing within a genus or family. For example, acidophilus is the name of a species within the Lactobacillus genus.

STRAIN: A probiotic ‘strain’ is a genetic variant or subtype of a species. Different probiotic supplements contain different strains, which may be classified under the same species and genus. However, one acidophilus is not equal to another acidophilus. It’s the strain level that matters when you choose a probiotic in order to help with a specific health condition. If you're looking to take a probiotic, make sure to look out for robust, well researched strains when choosing the right one for you.

When choosing a probiotic supplement what truly matters is the strain - specifically, well-researched strains with clinical evidence supporting their benefits. For example, Lactobacillus acidophilus Rosell-52 is a strain that has been studied for its role in managing antibiotic-associated diarrhea. 

After all, when choosing a dog there is a difference between embarking on life with a Labrador or a Dachshund.

Is there a difference between live cultures and probiotics?

While the terms live cultures and probiotics are often used interchangeably, they are not exactly the same. Live cultures are present in fermented foods and drinks such as yogurt, kimchi, kombucha, and kefir. However, according to the scientific definition, probiotics are microorganisms that have been clinically studied and shown to provide health benefits when consumed in adequate amounts.

It is important to note that the live cultures found in fermented foods are not usually tested in clinical trials, meaning their specific health benefits remain unproven. Additionally, fermented foods rarely provide a guarantee regarding the types or quantities of live cultures they contain. Therefore, it is generally more accurate to refer to these foods as containing live cultures, while reserving the term probiotics for foods and supplements that have undergone scientific research and demonstrated health benefits in humans. For further details, see our discussion on the Food Myth.

If you are considering taking a probiotic or prebiotic but are unsure where to start, consulting a specialist is recommended. The right choice will depend on your specific health concerns, as different probiotic strains support different areas of health.

What’s the difference between Probiotics, Prebiotics, and Postbiotics?

Probiotics definition is the beneficial microbes which live in our gut, whereas prebiotics are a source of food for probiotics. Prebiotics help our good gut bacteria to grow, multiply and thrive. For more information, take a look at our article What are Prebiotics?  This name for a combination of probiotics and prebiotics in a supplement is 'synbiotic' .

Postbiotics are still a developing area of the category - in simple terms, they are the beneficial end products of bacteria.

Key takeaways:

• The gut microbiome is the collection of microscopic bacteria and yeasts that naturally live in our gut
• Probiotics are the bacteria that can be beneficial for our health. They are made up of a genus, species and a strain, and are all very different.
• Probiotics can be taken in supplement form and they can also be found in fermented foods and drinks.
• The best probiotic supplement for you depends on the condition you are looking to support - immune health, digestive health, mental health, skin health and more.

We hope we have answered all of your questions about what are probiotics. 

Here are some Frequently Asked Questions about probiotics:

How do I determine which specific probiotic strain is best for my health needs?

Consider the research behind each strain and their specific benefits. Choose a strain that aligns with your health needs.

Are there any potential side effects associated with taking probiotics?

While probiotics offer many potential benefits with minimal side effects, it's important to be aware of mild symptoms like bloating or gas, especially when starting a new supplement. Probiotics are not recommended for use in a few serious medical conditions including those who are severely immunosuppressed.

Can probiotics be harmful if taken in excessive amounts?

It's important to follow recommended dosage guidelines and focus on consuming probiotic-rich foods in moderation to maintain a healthy balance. Excessive consumption of probiotics isn’t usually a problem, but may disrupt the natural balance of gut bacteria.

The Probiotics Database provides more detailed information on some of the most researched strains in the world, and explores the clinical research behind different strains, for different circumstances. Health professionals can read about probiotic strains on the Probiotics Database 

Interested in finding out more? Read these articles:

Which Probiotics are the Best for Women?

The Gut-Brain Axis and Probiotics

Gut Health – All You Need to Know

What are Human Strains

References

1. Markowiak P and Śliżewska K (2017) Effects of Probiotics, Prebiotics, and Synbiotics on Human Health. Nutrients, 9(9): 1021
2. Magnúsdóttir S, Ravcheev D, de Crécy-Lagard V, Thiele I (2015) Systematic genome assessment of B-vitamin biosynthesis suggests co-operation among gut microbes. Frontiers in Genetics, 6, 148
3. O’ Kennedy D (2016) B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review. Nutrients, 8(2): 68
4. Rodríguez-Olleros C, Curiel MD (2019) Vitamin K and Bone Health: A Review on the Effects of Vitamin K Deficiency and Supplementation and the Effect of Non-Vitamin K Antagonist Oral Anticoagulants on Different Bone Parameters. Journal of Osteoporosis, Article ID 2069176