Probiotic – Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.
Probiotics are available in different products including foods, dietary supplements, and infant formula.
Prebiotic – A substrate that is selectively utilised by host microorganisms conferring a health benefit.
Prebiotics can be found naturally in our diet such as onion and garlic or as supplements.
Symbiotic – These are combinations or pro- and prebiotics. The prebiotic compound must selectively favour the probiotic compound.
Classifying a Probiotic
A probiotic is classified into three components
- Genus (e.g. Lactobacillus)
- Species (e.g. casei)
- Strain (e.g. Shirota)
Knowing the strain of the probiotic is crucial as the health benefits of a bacterium are strain specific.
What about Fermented Foods?
Fermented foods should not be called probiotics as the microorganisms may only have fermentative capabilities, and do not necessarily have probiotic functions that confer a health benefit. Some fermented products are processed by heat or filtration to extend the shelf life, thus killing the microorganisms. They also do not list the strains of bacteria.
Do probiotics work?
The evidence for taking probiotics to treat IBS has been comprehensively reviewed and published by the British Dietetic Association. Specific probiotic recommendations for IBS management in adults is not possible at present and more research is needed. Research evidence should be available from the manufacturer so contact the company or check with your dietitian, to find supporting research. Probiotics may be beneficial for treating other medical conditions including constipation, Diverticular disease, Ulcerative colitis, and pouchitis. There is a huge surge in gut microbiota and probiotic studies that stretch far beyond digestive health benefits and immune system support. Further human trials are required before use of probiotics as a preventative or treatment in these emerging areas can be advised.
Check for GI tract survival
For a Probiotic to successfully balance gut bacteria, it must arrive, survive the stomach acid and then thrive in the target area of the gut. There are many Probiotics available that have not been validated to show that their probiotic can survive the passage through the stomach. Companies should provide research papers describing human studies (not in vitro or model studies) showing gut survival.
How long should I take a probiotic for?
NICE guidelines recommend that adults with IBS who choose to try a probiotic should be advised to take the product for a least 4 weeks while monitoring the effect. Probiotics should be taken at the dose recommended by the manufacturer. Only one probiotic should be trialled at a time.