The Probiotic Series: An Introduction to Probiotics

A picture of a woman's hand holding one probiotic tablet, in the background is the probiotic pill bottle.

Probiotics are the latest health trend. You’ve probably seen them in your local supermarket or had your friend go on about the supposed health benefits. This is a rapidly expanding industry, with sales of probiotics exceeding $35 billion in 2015 and set to reach $65 billion by 2024(1). However, as with all things nutrition, there is a lot of misinformation and people trying to sell you things that will cost you an arm and a leg but have no benefit to you what so ever. 

To understand how probiotics can benefit you, we first need to understand what they are. So let us go back to basics and find out what probiotics are and how they might benefit you. 

What are Probiotics?

You have trillions of microorganisms living inside your digestive tract. This isn’t just the good and bad bacteria you have likely heard about but also fungi, viruses, and more. This is what makes up our microbiome. Some of these microorganisms can be good for us, or bad, or simply neutral. 

Probiotics make up part of that microbiome. They are considered ‘good’ bacteria that when given in adequate amounts can promote health benefits(2). They can be found naturally in the foods we eat such as yogurt or kombucha (take a look at the linked article if you want to learn more about this tasty drink Kombucha – Worth The Hype?) or in a supplement. 

While sales of probiotic products and foods are currently sky rocketing, probiotics are not a recent discovery. They were actually discovered in 1907, by a Nobel prize winner called Elie Metchnikoff. He noticed that certain individuals of the Bulgarian population were living longer than others. He found that those who were drinking fermented yogurt daily, which contained the probiotic Lactobacillus bulgaricus, had improved health(3).  

the word probiotic is actually derived from a greek word that means ‘for life’

How do probiotics work? 

Sometimes, our gut can become out of balance, known as dysbiosis, where we have more bad bacteria than good. This can be caused by a variety of factors such as taking antibiotics, developing food poisoning, IBS or ageing(4).

When you take a probiotic, if it survives passing through our stomach and makes it to our gut, the good bacteria can take over the bad bacteria. The good bacteria compete for space with the bad and it can eventually out grow it. It takes over the bad bacterias food source and space. As this happens you may notice your digestive system begins to feel healthier. Your digestion might improve and any digestive upset such as bloating for example might decrease(5).  

The bad bacteria produce toxins which can effect our wellbeing. The probiotics not only reduce the amount of bad bacteria in your gut but also create beneficial products such as  short chain fatty acids. These SCFA’s discourage future growth of bad bacteria, create a healthier gut environment and have been shown to reduce our risk of infection and inflammation(6)

Probiotic Strains

If you have ever picked up a probiotic supplement, you might see the variety of strains of probiotics it contains. 

A strain is a type of bacteria and lets us known in depth more about that bacteria. It can be broken down by genus, species and then strain. 

For example: 

Genus –  Bifidobacterium

Species – Lactis

Strain – DN-172 010 (or you might see its nickname)

Some of the most common probiotics you are likely to see include: 

  • Bifidobacterium bifidum
  • Bifidobacterium lactis
  • Bifidobacterium longum
  • Lactobacillus casei
  • Lactobacillus bulgaricus
  • Lactobacillus plantarum 
  • Lactobacillus acidophilus
  • Saccharomyces boulardii

While this is not a definitive list of all the strains you might see on the market, these are some of the more commonly researched strains. 

What is the difference between Bifidobacterium and Lactobacillus?

In the common types of probiotics that have been studied, you can see a majority either start with bifidobacterium or lactobacillus. Both of these are a type of probiotic but they have different benefits and function slightly differently from each other. 

Firstly, they live in different parts of the intestine. You’ll find lactobacillus in the small intestine and bifidbacterium in the large intestine (your colon). They also produce different by-products which have different benefits. 

Lactobacillus creates lactic acid. The health benefits of this include(7)

  • Controlling infections in the intestine
  • Improved digestion of lactose 
  • Helps to control your serum cholesterol 
  • General healthy digestion and improvement in bowel regularity

Bifidobacterium produces short chain fatty acids.There are many reported health benefits from taking bifidbacteria however a few general health benefits include:

  • Helping us to properly digest fibre
  • Helping to maintain normal healthy gut function
  • Keeping a healthy immune system
  • Help prevent infections 

Who Should Take a Probiotic?

We know that there’s a link between having a healthy gut and improving your overall health including immune function and reducing your risk of developing a chronic illness. Good gut health has also been shown to help improve your mental health. However, current research on probiotics are mixed and unless you have a specific concern in mind you think a probiotic might help with you are probably just as well off to focus on eating a healthy balanced diet that includes probiotic containing foods.

That said, in certain studies, probiotics have been found to help certain condition. 

You may consider taking a probiotic if you have any of the following(8):

  • A Gastrointestinal disorder e.g antibiotic associated diarrhoea, c.diff, constipation, IBD or travellers diarrhoea
  • Eczema
  • Lactose intolerance 

It is worth keeping in mind that certain conditions have only been studied with certain types of probiotics. So if you pick a probiotic of the shop shelf it may not work for you. This is also not a definitive list on the conditions probiotics may help with. Research is still very much ongoing and there are new discoveries everyday. I will go into more detail in later posts about different conditions and the probiotics that work best for them. 

What Are The Health Benefits Of Probiotics?

Again, as with the above conditions, the health benefits of probiotics can be strain dependant and in many areas, more research is needed to confirm these benefits. However, some more general health benefits have been found to taking a probiotic. 

Taking a probiotic or including more probiotic rich foods may help to(9,10):

  • Improve digestive health 
  • Reduce your risk of developing heart conditions
  • Improve your immune response
  • Improve lactose intolerance 
  • Reduce your risk of developing certain cancers
  • Alleviate the effects of allergies such as hay fever
  • Better oral health 
  • May help you maintain a healthy weight 

The Takeaway

Probiotic research is an ever evolving field and there is so much more to learn and understand about them. But hopefully, you now have a better understanding of what a probiotic is and how they might benefit you and your gut. 

Over the coming months I will continue to dive into all things probiotics, taking a particular interest in how they may help those with IBS and what the best probiotics on the market are.  Let me know in the comments if you take a probiotic and if you have found any benefits from it.


  2. Organisation FaO WHO (2001) Evaluation of health and nutritional properties of probiotics in food, including13ª2016 The British Dietetic Association Ltd.Y. A. McKenzie et al. Guidelines on probiotics in IBS management powder milk with the live lactic acid bacteria. Report of aJoint FAO/WHO Expert Consultation.Geneva: WorldHealth Organization.
  3. Merenstein, D. and Salminen, S., 2017. Probiotics and prebiotics.
  6. Sánchez, B., Delgado, S., Blanco‐Míguez, A., Lourenço, A., Gueimonde, M. and Margolles, A., 2017. Probiotics, gut microbiota, and their influence on host health and disease. Molecular nutrition & food research61(1), p.1600240.
  7. Gilliland, S.E., 1990. Health and nutritional benefits from lactic acid bacteria. FEMS Microbiology reviews7(1-2), pp.175-188.
  9. Pandey, K., Naik, S. and Vakil, B., 2015. Probiotics, prebiotics and synbiotics-a review. Journal of food science and technology52(12), pp.7577-7587.
  10. Kechagia, M., Basoulis, D., Konstantopoulou, S., Dimitriadi, D., Gyftopoulou, K., Skarmoutsou, N. and Fakiri, E.M., 2013. Health benefits of probiotics: a review. International Scholarly Research Notices2013.

Photo by Mariana Rascão on Unsplash

4 responses to “The Probiotic Series: An Introduction to Probiotics”

  1. […] the antioxidants found in the tea (2). If you want to learn more about probiotics head over to my introduction to probiotics […]

  2. […] can be great for your digestive health due to its probiotic nature and fibre […]

  3. […] Want to learn more about these cool microorganisms? Check out my post An Intro To Probiotics.  […]

  4. […] people are hopping on the probiotic bandwagon, eating their fill of probiotic-rich foods or taking a probiotic supplement on the quest […]

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