Colonic health and bacteria

The incidence of human intestinal inflam¬mation and inflammatory bowel disease has increased steadily in the Western world since the early 1950s.
The human ‘gut flora consists of between 300 and 1,000 microbial species, and some 1014 microorganisms in total (about ten times the number of cells of the human body). They synthesize essential vitamins and amino acids, and also degrade otherwise indigestible plant material, as well as certain drugs and pollutants.
In Nature vol 453 May 29th 2008 pages 602-3 and 620-625 Kullberg and Mazmanian describe how there is a microbial symbiosis factor acting in the intestine. Mazmanian et al report that Bacteroides fragilis, a commmon bacterium of the lower gastrointestinal tract in mammals, can prevent intestinal inflammation in mice. Polysaccharide A (PSA) of B.fragilis prevents gut inflammation induced by another bacterium, Helicobacter hepaticus, or by the chemical compound TNBS (2,4,6-trinitro-benzene sulphonic acid).
This is importance to Nutritionists as it raises the prospect of changing the bowel flora with appropriate nutrients which pass to the colon eg fibre which may be of importance.

Martin Eastwood
Back to top