Probiotics: Their Impact on the GI Tract
The probiotic bacteria belong to the transient species, as their presence in the GI tract is always dependent on food intake. Some of the beneficial effects of probiotics intake include the improvement of GI health by regulating the microbiota, the stimulation and development of the immune system, the synthesis and enhancement of the bioavailability of some nutrients, the alleviation of the symptoms of lactose intolerance, and the reduction of the risk of certain diseases, mainly through the modulation of unbalanced indigenous microbiota (Collado, 2009). As mentioned in the literature, the more common dysbiosis-related diseases are coelic desease, colon cancer, HIV infection, type I diabetes, type II diabetes, atopy (allergy), inflammatory bowel disease, irritable bowel syndrome, gastrointestinal infections, antibiotic-associated diarrhea (AAD), necrotizing enterocolitis, obesity, and rheumatoid arthritis (ILSI Europe, 2013).
Studies on some probiotic strains have demonstrated an impact on gut function in terms of normalization of transit time and reduction of self-reported minor digestive discomfort symptoms (ILSI Europe, 2013).
An improved transit time may reduce putrefactive activity in the colon. These effects may be considered positive for the host, as the risk of constipation is decreased. This beneficial effect may also be correlated to prebiotics that, by their fermentation activity in the colon, contribute to increase the bacterial mass, the osmotic water-binding, the stool weight, and frequency.