Updated 29 January 2014

Quick facts about probiotics

Researchers are starting to realise that probiotics can have a major impact on our health. What should you know about the micro-organisms that live in your intestinal tract?

During the past 10 years, "probiotics" have become an important concept in scientific circles.

Today, more and more researchers are starting to realise that these "good bugs" have a major impact on our health.

Probiotics, or non-disease causing micro-organisms that can be ingested through food or supplements, have been shown to play a positive role in immune regulation, the absorption of nutrients, and the treatment of diarrhoea in both children and adults.

But what else should you know about the micro-organisms that live in your intestinal tract? Here are a few quick facts:

  • Your intestinal tract is colonised with over 100 000 billion micro-organisms. This means that there are approximately 10 times the number of micro-organisms in your body than there are cells!
  • Your body plays host to more than 500 different species of bacteria. Only 50% of the strains are known to mankind.
  • The microbiota in your intestinal tract are able to cover a full tennis court, if unravelled. "Microbiota" refers to micro-organisms in a specific environment.
  • It is estimated that the average adult has between one and two kilograms of bacteria in the intestine at any one time.
  • Most of the bacteria just live in our intestinal tract, doing nothing to us, but many others are essential to our well-being.
  • Many of the micro-organisms that live in our bodies are "transient" – this means that they move on to a different host after a while.
  • Only a few types of bacteria are harmful to us and may cause disease.
  • The bacteria genome is vastly more complex than the human genome. "Genome" refers to the total genetic material of an organism.
  • All babies are born completely sterile. A baby's gut microbiota is established during the first few months of life. After this period, the microbiota remains remarkably stable, only to be upset by powerful antibiotics, poor eating habits and stress during a person's lifetime.
  • The combination of micro-organisms present in the gut is unique for every individual – almost like fingerprints.
  • Lack of exposure to health-promoting micro-organisms is thought by many to be the reason why certain diseases like allergies and asthma are increasing in affluent societies.
  • In order to work effectively, a true probiotic needs to be derived from human origin – usually cultivated from breastmilk and from the microbiota found naturally in the intestinal tract.
  • Currently, there are only a few strains of bacteria that can be safely recommended as having beneficial, probiotic qualities. These include the Lactobacillus and Bifidobacterium strains.


  • Bengt Björkstén, Professor of Allergy Prevention and Paediatrics, Centre for Allergy Research, Karolinska Institutet, Sweden.
  • Thebe Pharmaceuticals

(Photo of woman placing hand on belly from Shutterstock)


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