Allergy, Eczema, Digestion, Asthma, Infant and Children | December 4, 2014 | Author: The Super Pharmacist
Probiotics and prebiotics are terms often used in the marketing of specialised foods and supplements. They are often accompanied by claims of improving health, mainly from a gastrointestinal or immunological standpoint. Probiotics are distinct substances (and products) as opposed to prebiotics, which are compounds from foods, although they do interact in order to carry out their purported health benefits. Probiotics have been linked to possible improvements in conditions such as Crohn's disease, viral conditions such as upper respiratory tract infections, and eczema.
However, some regulatory authorities are uncertain about granting official sanction or recognition for them in the role of pharmaceutical or nutraceutical products. This is generally due to the low volume of full clinical trials that include human subjects with appreciable results. This article will discuss prebiotics, probiotics, how they differ and the evidence to support their role in human health.
Probiotics are in fact bacterial cultures. They are the various types of these micro-organisms that exist normally in the human gut contributing to the breakdown of food and, according to some researchers in the field, to optimizing levels of more general health.
There are many species of probiotics, of which Lactobacillus and Bifidobacteria are particularly prominent and recognisable in marketing terms. They are often included in the description of a foods, such as yogurt, along with their sub-species.
Many have patents or similar intellectual-property protection included in order to give weight to the health-promoting claims.
It is true that these probiotic bacteria play often specific roles once in the gut, such as:
In addition, probiotics are associated with a number of effects on the immune system. These include:
The perceived need for supplementary probiotics may be based on apprehensions that modern diets or lifestyles may inhibit the normal levels of their growth in the gastrointestinal tract.
However, for the ingestion of products that claim to address this to be effective, the bacteria must reach their appropriate locations in the gut alive. The upper gastrointestinal tract, particularly the stomach, acts to kill any bacteria ingested, due to exposure to stomach acid. Therefore, the required amount of probiotics may not survive ingestion, and thus fail to elicit any beneficial effect on the gut. Variations in individual diet, metabolism and immune function may increase the probability of this.
Probiotics are compounds from foods, such as fibres, which induce the growth and activity of beneficial microorgasms - probiotics. Prebiotis are another strategy by which probiotic levels may be increased. This is through the use of the dietary components metabolised for nutrients and fuel by these bacteria. These molecules may be termed 'prebiotics' as they promote the growth of existing beneficial bacteria.
Dietary fibre - often deficient in the modern diet. Fibre is made up of complex carbohydrates, the basic unit of which are sugars, but when linked together these molecules form a much more elaborate structure.
Oligosaccharides - which are complexes of a smaller number of sugar units (from the Greek; oligos: 'a few', and saccharide: sugar). Probiotic bacteria (also known as the normal gut microflora) use these molecules.
There are some specific oligosaccharides associated with microflora promotion. These select beneficial bacteria, particularly Bifidobacteria, which inhibits the spread of other species associated with disease. They include:
Some of these oligosaccharides are resistant to gastric acid, rendering them yet more advantageous as oral applications to modulate intestinal flora. Therefore, supplementation with these may increase normal microflora, and thus effect potential immune system stimulation.
Oligosaccharides are found in human breastmilk and are passed on to an infant who is not yet on solid food.
The number and diversity of intestinal microflora has been found to be increased in breast-fed infants compared to those who were bottle-fed. This is linked to improvements in the immune system of the child in general.
Some preliminary evidence indicates that the administration of prebiotics to infants resulted in the reduced incidence of autoinflammatory conditions, and an increase in probiotic bacteria.
One study (not a clinical trial) found that breastfeeding for six months or more in the absence of other food sources reduced the incidence of eczema by 60%. A meta-analysis of 18 human trials involving infants, nursing mothers and/or pregnant women receiving prebiotics or probiotics concluded that probiotic supplementation alone was associated with the reduced incidence, but not symptom severity, of eczema in infants aged two years or under.
Another meta-analysis of studies on the effects of prebiotics on infantile allergies found a significant reduction of eczema, but not similar conditions such as asthma or uticaria. This indicates a need for further research in order to fully define the actual therapeutic applications of prebiotics.
Manufacturers of probiotics face other problems when seeking to verify their claims. Storage conditions unsuitable for bacteria may decrease the probiotic content of the products concerned. Food authorities can also prevent labelling claims. The European Food Safety Authority reject evidence-based approval for several probiotic species. In addition, the fact that it is against European law to state that any food has medicinal properties, affects probiotic success and therapeutic validity in a major market.
The obvious route to scientific and regulatory acceptance for probiotics is to present them as pharmaceutical or nutraceutical products. However, this entails a possibly significant increase in the clinical and safety testing required, which may result in an equally significant increase in expense. This may inevitably lead to an increase in the price of the final product, thus impacting on the continued success of probiotics as a viable commercial concern.
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