Probiotics and their role in the gastrointestinal health: selection criteria and human in vivo study

Introduction Since some years an increasing number of common people, being part of the so-called consumers, showed an high interest toward probiotics having been spread all over the word the knowledge on their beneficial effects on health. Previous studies (1, 2) have found that by providing probiotic functional foods enriched with the combination (1:1) of two probiotic bacterial strains, Lactobacillus rhamnosus IMC 501® and Lactobacillus paracasei IMC 502® determined their persistence in the intestinal tract favouring the natural regularity and contributing to maintain and improve intestinal well-being of consumers. Moreover the availability of probiotic in capsules may be useful in particular conditions and for some categories of people. Materials and methods The present study was a randomised, double-blind, placebo-controlled, parallel group study assessing the effect of daily consumption of the combination, named SYNBIO®, by probiotic-enriched foods or by dietary supplement on the bowel habits of healthy adults. The study was performed with a 4-week run-in period followed by a 12-week intervention period. Primary and secondary outcomes gave the overall assessment of bowel well-being, a self-administration of Psychological General Well-Being Index (PGWBI) estimated the health-related quality of life and gastrointestinal tolerance was determined with the Gastrointestinal Symptom Rating Scale (GSRS). Support Vector Machine models for the classification problem have been used to validate the total outcomes of the bowel well-being. Results SYNBIO® consumption enhanced of bowel habits of volunteers consuming the SYNBIO®-enriched foods and capsules. In fact, the same effects were not registered in the control groups. The recovery of probiotic bacteria from the faeces of a cohort of 100 subjects for each supplemented group showed the persistence of strains in the gastrointestinal tract of people. Consumption of probiotics in several food matrices yielded high quantity of the two strains, and capsules provided a comparable means of administration. 1) Verdenelli MC, Ghelfi F, Silvi S, Orpianesi C, Cecchini C, Cresci A (2009). Probiotic properties of Lactobacillus rhamnosus and Lactobacillus paracasei isolated from human faeces. European Journal of Nutrition 48:355-363. 2) Verdenelli MC, Silvi S, Cecchini C, Orpianesi C, Cresci A (2011). Influence of a combination of two potential probiotic strains, Lactobacillus rhamnosus IMC 501® and Lactobacillus paracasei IMC 502® on bowel habits of healthy adults. Letters in Applied Microbiology 52: 596-602.