The Uses of Prebiotics
Feeding the healthy bacteria for a better intestinal ecosystem
By Dr Georges Mouton
In 1995, Gibson and Roberfroid coined the concept of prebiotics in these words: “Non digestible oligosaccharides in general and fructo-oligosaccharides in particular, are prebiotics. They have been shown to stimulate the growth of endogenous bifidobacteria”1. Two key properties of short chain fructo-oligosaccharides prebiotics which lead to physiological functions are indigestibility in the small intestine and fermentability in the colon. They are converted into short chain fatty acids (SCFAs) by intestinal bacteria, especially by Bifidobacteria, and these SCFAs largely feed the colonocytes2.
The best dietary prebiotics sources are artichokes (especially Jerusalem artichokes), onions and leeks (in fact the whole Allium family), asparagus, salsify, and chicory - the latter representing by far the dominant source for commercialized prebiotics. Fructo-oligosaccharides are characterized by a smaller degree of polymerization (less than 10) whereas inulin - mostly extracted from chicory (Cichorium intybus) - covers as much as 60 degrees of polymerization. Most of scientific research has been performed with inulin, hydrolyzed or not, even though other types of prebiotics exist, such as lactulose.
Interest of prebiotics for supporting the immune system has been extensively published: their immune-enhancing effects3 apply to all age categories, from infants4 to elderly patients affected by Clostridium difficile5. Besides, more and more evidence is accumulating in favor of a powerful protective effect towards colon cancer, and the involved mechanisms include the reduction of exposure to risk factors as well as the suppression of tumor cell survival6. Regarding colitis, the studies show how prebiotics improve the gut mucosal barrier and modulate the microflora, thus they could help in the prevention of Inflammatory Bowel Diseases [IBD]7. “This novel therapeutic strategy appears to decrease Crohn's disease activity in a small open label trial”8. Besides, very encouraging results have been obtained in Ulcerative Colitis and the use of prebiotics9, 10.
Relieving constipation represents a considerable practical application for prebiotics, both due to their safety and efficacy2. In another field, prebiotics improve the absorption of several minerals, mostly calcium11 and magnesium12, which positively affects bone mineralization especially during pubertal growth13. Another field where prebiotics deserve our clinical interest is relieving liver steatosis14, including a significant decrease of serum transaminases justifying the use of prebiotics “in the management of liver diseases associated with abnormal lipid accumulation in humans”15.
Perhaps the major interest for prebiotics lies in their capacity to promote satiety and decrease absorption of macronutrients, thus helping to prevent obesity16. Besides, “dietary fiber intake may modulate parameters associated with the control of the metabolic syndrome, namely food intake (and body weight), glycemia and insulinemia, blood lipids and blood pressure”17. Prebiotics decrease the mean daily energy intake mainly through the modulation of gastrointestinal peptides, an array of hormones that control our appetite and satiation; they boost the secretion of glucagon-like peptide-1 (GLP-1) and of peptide YY (PYY) - two major satiety promoting peptides released by the colon - whereas they reduce the production of ghrelin, an orexigenic (triggering appetite) stomach-secreted peptide18. The first human pilot studies available justify using prebiotic supplements in the management of food intake in overweight and obese patients19.
Dr Georges Mouton is registered with the General Medical Council in the UK, is a Fellow of the Royal Society of Medicine in London, and is also registered with the Spanish Ministry of Health - his current country of residence. Born in Haiti to Belgian parents, Dr Georges Mouton is an internationally renowned expert in Functional Medicine. At his practices in London, Madrid and Brussels Dr Mouton offers dietary and nutritional counselling, combined with administration of appropriate vitamins and minerals. His speciality lecture topics include probiotics and fatty acids.
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