Probiotics are microorganisms (almost always bacteria) that have beneficial effects on the body and its functioning.
These microorganisms are the same or similar to those that occur naturally in the human body. Each of us have up to 100 trillion bacteria, good and bad, in our digestive systems.
Probiotics – both those that occur naturally in the body and those obtained from food and/or supplements – are largely concentrated in the gastrointestinal (GI) tract, where they form part of the intestinal flora. Healthy intestinal flora is an essential part of digestion.
An imbalance of pathogenic (harmful) bacteria vs. healthy bacteria can have a number of negative health consequences.
Some of the most common probiotic strains are those that form part of the Bacteroides family. These make up approximately 30% of all the bacteria in the gut.
The most common strains of probiotics include:
- Lactobacillus acidophilus
- Lactobacillus bulgaricus
- Lactobacillus casei
- Lactobacillus gasseri
- Lactobacillus plantarum
- Bifidobacterium bifidum
- Bifidobacterium lactis
- Bifidobacterium longum
- Enterococcus faecium
- Saccharomyces boulardii
What research shows
Over the past few decades, research into the field of probiotics has exploded.
The studies that have been conducted so far show promising results with regards to the effect that probiotics may have on gut health and integrity.
For example, probiotics have been used with some success to reduce and improve symptoms of various gut diseases and disorders such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS).
Other potential benefits include weight maintenance, as large cohort studies have shown strong associations between the consumption of fermented dairy foods (e.g. yoghurt) and weight maintenance.
Keen to learn more? Watch this video for more information on how the human microbiome works.
Reviewed by Kim Hofmann, registered dietitian, BSc Medical (Honours) Nutrition and Dietetics, BSc (Honours) Psychology. April 2018.