There are no convincing data at present demonstrating efficacy of probiotics in non-infective diarrhoeal disorders. Although the use of probiotics in diarrhoeal diseases is conceptually appealing, their use for this indication is not clearly supported by the available scientific literature at present. Further research into the role of the human microflora in diarrhoeal diseases is needed to aid the selection of appropriate non-pathogenic bacteria for clinical studies. Well conducted controlled clinical trials are then needed in order to determine the place of probiotics in the prevention and treatment of diarrhoeal disorders. Amongst other substances, the short chain fatty acid butyrate is produced during fermentation.
Dietary fibres differ greatly in their physicochemistry and also in their biological effects.
In humans, resistant starch results in substantial production of butyrate in the colon. The nature of the variables affecting butyrate production from dietary polysaccharides by resident microflora need to be explored with a view to better understanding the practical application of this to cancer prevention. This review examines some of the evidence regarding probiotic bacteria as agents to reduce the risk of colon cancer in humans. While some of the evidence using rodent models of colon cancer is convincing for a reduction in cancer incidence and burden with the introduction orally of such bacteria as Bifidobacterium longum , Lactobacillus acidophilus and gg, convincing evidence in humans is more difficult to find. Taken together these sources of data provide limited support for the hypothesis that probiotic bacteria are effective in cancer prevention.