Probiotic, Prebiotic and Synbiotic Foods
Probiotics are by definition living microbiological dietary supplements that have beneficial effects to the host through their function in the digestive tract (1, 2).
In order to be effective the probiotic micro-organisms must be able survive the digestive conditions including bile acids, and they must be able to colonise the gastrointestinal tract at least temporarily without any harm to the host. Only certain strains of micro-organisms have these properties. Most probiotic micro-organisms are members of two bacterial genera: Lactobacillus and Bifidobacterium.
Lactobacilli and bifidobacteria belong to the natural colonic flora. With probiotic foods the number of these beneficial bacteria is increased and maintained at a high level. Among the most common probiotic microbes are strains of Lactobacillus acidophilus and Bifidobacterium lactis (or Bifidobacterium bifidum).
Prebiotic carbohydrates. Certain nondigestible carbohydrates, such as components of soluble dietary fibre may stimulate the growth or activity of beneficial/probiotic bacteria. Such components in food are called prebiotic and they can naturally occur in food or they can be specific supplements (2).
The soluble dietary fibre present in many foods of plant origin serves as colonic food although it is not quite clear if all soluble fibres favour the beneficial flora and how.
Synbiotic foods. A combination of probiotic micro-organisms and prebiotic carbohydrates is called synbiotic food (2). There are dairy products on the market, mainly probiotic yoghurts with added fructo-oligosaccharides.
There is evidence supporting the function of the soluble fibre from oats as a prebiotic component, thus suggesting that a vellie is indeed a synbiotic food (3, 4, 5).
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