Commentary Cellscience Reviews Vol 1 No.1 ISSN 1742-8130

Promoting bacterial culture : the importance of Probiotics and Prebiotics to Good Health

James Collier

Introduction

Currently, there is huge interest in the use of foods which may exert a positive functional effect on our health. Two of these ‘functional foods’ are known as probiotics and prebiotics, both of which have a favourable effect on the ‘good’ bacteria that reside in our digestive systems, also known as our gut microflora. These ‘good’ bacteria live naturally in our intestines and are essential to good health having a number of positive effects, primarily helping our digestive systems work efficiently. We traditionally view bacteria as being ‘bad’; however in reality there are relatively only a small number of strains which are pathogenic and most microbes are harmless and contribute to well-being (Gibson 2003).

What are Probiotics?

Probiotics are live strains of these ‘good’ bacteria, which help our digestive system work efficiently, e.g. bifidus, lactobacillus and acidopilus. A probiotic may be defined as: ‘A preparation or product containing viable, defined micro-organisms in sufficient numbers, which alter the microflora of the host intestine and, by that, exert beneficial health effects on the host’ (Schrezenmeier & De Vrese 2001).

They are found in live yoghurts or specially formulated powders, supplement pills or probiotic drinks which contain one or more of the strains of these bacteria. With food processing, pollution and antibiotic therapy, the numbers of bacteria living naturally in our gut are reduced, and research has shown that active consumption of bacteria increases the size of intestinal colonies, thereby improving digestion of food. Moreover, numerous studies have also shown that with optimal numbers of ‘good’ bacteria, the immune system is improved, increasing our ability to fight disease (Gibson & Roberfroid 1995). Probiotics may also have a role in reducing the severity of food allergies and intolerances, and may help reduce severity of symptoms in both osteo- and rheumatoid arthritis.

What are Prebiotics?

Prebiotics can be defined as nutrients and constituents of food which our gut flora feed upon, thus increasing their numbers. Prebiotics include fructo-oligosaccharides, which are found naturally in many plants including leeks, onions, wheat, garlic, chicory root and artichokes where they function as storage carbohydrates, and some other soluble fibres found in pulses, fruit and some cereal products. Fructo-oligosaccharides are low molecular weight carbohydrates, and since they are not broken down significantly by the digestive processes in the stomach and small intestine, they are classified as dietary fibre. However, fructo-oligosaccharides are water soluble, being non viscous ‘fructans’ and have a low water retention capacity. Structurally they are a mixture of polymers (chain repeats of the same unit molecule) and oligomers (chains composed of different molecular units), comprising branching chains of between 10 and 60 units of fructose (see figure). Thus prebiotics also help digestion and the immune system by increasing microflora levels.

Prebiotics have also been incorporated into supplements and functional foods, in order to exert positive effects on the digestion, the immune system and possibly some degenerative diseases. Indeed one Swedish study (Orrhage et al, 2000) followed thirty individuals to study the effect on the intestinal microflora of oral supplementation with probiotics (Bifidobacterium longum, Lactobacillus acidophilus) and the prebiotic oligofructose (an indigestible oligosaccharide) during the oral administration of an antibiotic for seven days. All individuals showed a marked decrease in populations of microorganisms, notably a rapid and almost complete disappearance of Escherichia coli and bifidobacteria during antibiotic administration, which was accompanied by an overgrowth of enterococci and intestinal yeasts. Although the number of lactobacilli also decreased, the population was higher in those individuals who received both daily prebiotic and probiotic supplements. This study demonstrates not only the susceptibility of healthy gut flora to antibiotics, but also the viability of prebiotic and probiotic supplementation.

Simply put, probiotics are foods which provide the actual ‘good’ bacteria, and prebiotics are those nutrients which the bacteria feed on to increase their numbers. The effect of a probiotic may be enhanced by having a prebiotic as the support medium; for example milk contains nutrients for lactobacillus, and so many probiotic drinks are milk or yoghurt-based.

Probiotics and prebiotic formulas are proving very popular and many of you will have seen them on television, in consumer press and in the shops. This is because, unlike many nutrition trends, the evidence that they promote good health is strong (Gibson 2003). Not only do they help us digest our food, but they may also help reduce the severity of food poisoning and reduce effects of food intolerance. Users report that formulas also help improve general well-being and they may help improve performance in sport due to improved digestion of food and therefore increased availability of nutrients. Also improved immunity and reduction in illness means fewer interruptions in training.

Unless there is a rare and specific reason as to why an individual should not use probiotic formulas, it is strongly recommended that we all include them in our daily nutrition in order to ameliorate a range of nutritional and health disorders and to merely promote general good health and well being.

REFERENCES

Gibson GR (2003). Probiotics & Prebiotics and their Function. Functional Nutrition 2 (2): 11-13

Gibson GR, Roberfroid MB (1995). Dietary modulation of the human colonic microbiotica: introducing the concept of prebiotics. J of Nutr 125: 1401-1412

Orrhage K, Sjostedt S, Nord CE (2000). Effect of supplements with lactic acid bacteria and oligofructose on the intestinal microflora during administration of cefpodoxime proxetil. J Antimicrob Chemother. 2000 Oct;46(4):603-12.

Schrezenmeier J, De Vrese M (2001). Probiotics, prebiotics and synbiotics – approaching a definition. Am J Clin Nutr 73 (Suppl) 361s-364s