Evaluation of Lactobacillus Reuteri DSM 17938 + Vitamin D3 in the Prevention of RRI in Paediatric Patients

Several clinical trials documented the efficacy of probiotics in the prevention and treatment of acute gastroenteritis, while there is little evidence on the efficacy of the probiotics in the prevention of children respiratory infections.

The biological activity of probiotics is linked, partly, to their capacity to adhere to enterocytes. This would avoid the binding of pathogenic bacteria through a competitive exclusion mechanism. This inhibition toward pathogen bacteria on epithelial and mucosal level (substrate), thanks also to the production of antimicrobial substances, can have a beneficial effect on the balance of the intestinal microflora of the host and improve its immunity.

The adhesion of probiotic bacteria to the enterocyte membrane receptors influences the activation of second messengers that induces the production of cytokines. The presence of probiotic bacteria influences the commensal microorganisms in the production of lactic acid and bacteriocins. These substances inhibit the growth of pathogens and modify the balance of commensal bacteria of the intestinal bacterial flora.

Numerous controlled clinical trials show that L. reuteri DSM 17938 colonizes the human gastric and intestinal epithelium and modulates the immune response, particularly through CD4 + T-helper cells in the ileum. These data confirm the pre-clinical evidence obtained in animal models; furthermore these immunomodulatory effects may explain some clinical properties of L. reuteri DSM 17938 such as the prevention of diarrhea, inhibition of pathogen infectionand the following immune system response of the host to these pathogens, as well as the potential modulation of the immune response by the Th1/Th2 balance in the human intestinal epithelium, an answer that has been linked to the prevention and treatment of allergy. In a recent, randomized, double-blind, placebo-controlled clinical trial, L. reuteri DSM 17938, supplemented for three months to healthy children aged 6-36 months attending nursery schools, demonstrated not only a significant reduction of episodes and duration of diarrhea but also of respiratory tract infections with consequent reduction of costs for society.

Despite the prevalence of food with vitamin D and multivitamin products, reports regarding non-optimal vitamin D levels in adults and children in the world have increased, in particular among those subjects overweight and with dark pigmentation of the skin.

In addition to its well-known effects on bone health, vitamin D is indeed an important immune regulator, because it stimulates innate immunity and modulates inflammation. An analysis of data from the National Health and Nutrition Examination Survey (NHANES) between 1988 and 1994 showed an inverse relationship between vitamin D levels and the incidence of upper respiratory tract infections (URTI). These results were supported by other studies showing an increased risk of acute lower respiratory tract infections in subjects with low levels of vitamin D.

Historically, the association between rickets and the risk of serious respiratory infections is well known and vitamin D deficiency has been associated with an increased risk to contract the flu.

These considerations have led to the hypothesis that supplementation with a probiotic added with vitamin D3 may influence the composition of intestinal flora by improving the immune system and therefore reducing episodes of respiratory infections, particularly frequent during preschool age.