While the above studies validate the clinical efficacy of the VSL#3 compound in maintenance therapy of some inflammatory bowel diseases, previous human trials of other probiotic compounds have produced less convincing results. For example, while Rembacken et al demonstrated that a nonpathogenic strain of Escherichia coli (serotype 06:D5:H1), two capsules twice daily (2.5×1010 viable bacteria per capsule), was as effective as mesalazine (1.4 to 2.4 g/day) in maintaining remission in patients with ulcerative colitis, this study had several flaws. The patient group was heterogeneous with regard to the severity of the illness (mild to severe), and patients were treated with several different corticosteroid formulations as well as the study medication. Also, the doses of mesalazine used were relatively low, and only a very small number of patients remained in remission at the end of the study.
S boulardii, in combination with mesalamine, has recently been shown to be more effective than mesalamine alone in the maintenance treatment of inactive Crohn’s disease, and a combination of antibiotic and probiotic treatment using the VSL#3 compound was shown to be more effective than mesalamine in the prevention of postoperative recurrence of Crohn’s disease . These findings indicate that probiotics could represent a form of maintenance treatment for inflammatory bowel diseases. Prevention of colon cancer: The consumption of probiotics and/or prebiotics may have several antimutagenic effects, including the inhibition of mutagenic activity, a decrease in enzymes implicated in the generation of carcinogens and the suppression of tumours. For instance, lactic acid bacteria bind mutagenic pyrolysates produced during cooking at high temperatures as well as degrading carcinogens such as N-nitrosamines. Indeed, the link between high fat/low fibre Western-style diets and a higher risk of colon cancer can partially be explained by the alterations in fecal bacterial enzyme activity induced by a Western-style diet. Fecal bacterial beta-glucuronidase, nitroreductase, azoreductase and steroid 7-alpha-dehydroxy-lase have been implicated in the conversion of precarcinogens into carcinogens within the colonic lumen; furthermore, these enzymes are all increased in the colons of those consuming a high fat/low fibre diet. Tumour suppression by probiotics has been shown to exist in numerous animal models and the biological basis of the suppression attributed to either diminished neoplastic enzyme activity or immunostimulation of the host. However, there is not yet any direct evidence that probiotics can protect against the development of colon cancer.
Lactose intolerance: There is evidence to suggest that probiotics may have some use in the treatment of patients with lactase deficiency. During fermentation, lactic acid bacteria, especially L bulgaricus, produce lactase, which hydrolyzes the lactose in dairy products to glucose and galactose. It has been shown that lactose is better digested from yogurt than from milk by lactase-deficient individuals; furthermore, yogurt intake in these patients is paralleled by reduced symptoms. This effect of yogurt appears to be related to a high enzymatic content of beta-galactosidase.