Gut microbiota, probiotics, and vitamin D: Interrelated exposures influencing allergy, asthma, and obesity?

Abstract

Current evidence supports a role for gut colonization in promoting and maintaining a balanced immune response in early life. An altered or less diverse gut microbiota composition has been associated with atopic diseases and/or obesity. Moreover, certain gut microbial strain or strains have been shown to inhibit or attenuate immune responses associated with chronic inflammation in experimental models. However, there has been no fully adequate longitudinal study of the relation between the neonatal gut microbiota and the development of allergic diseases (e.g., atopic asthma) and obesity. The emergence of promising experimental studies has led to several clinical trials of probiotics (live bacteria given orally that allow for intestinal colonization) in humans. Probiotic trials thus far have failed to show a consistent preventive or therapeutic effect on asthma or obesity. Previous trials of probiotics have been limited by small sample size, short duration of follow-up, or lack state-of-the art analyses of the gut microbiota. Finally, there is emerging evidence that the vitamin D pathway may be important in gut homeostasis and in the signaling between the microbiota and the host. Given the complexity of the gut micriobiota, additional research is needed before we can confidently establish whether its manipulation in early life can prevent or treat asthma and/or obesity.

Specific Dietary Oligosaccharides Increase Th1 Responses in a Mouse Respiratory Syncytial Virus Infection Model

“…There is increasing evidence that environmental factors and diet correlate with host immune function and disease susceptibility. The best-known examples are correlations found in allergy-related diseases like atopy and asthma, but a relatively new disease, like obesity, also appears to be linked to a specific composition of the intestinal microbiota (30,47). This suggests that the microbial community and the host immune system continuously cross-communicate and reorganize, leading to a delicate balance.…”

Epigenetic Control of the Host Gene by Commensal Bacteria in Large Intestinal Epithelial Cells

“…Although the commensal bacteria are not immunological "self" to the host, the intestinal immune system, the largest immune system in the body, does not exclude them completely, resulting in a symbiotic relationship. Maintenance of the symbiosis between the intestinal immune system and the commensals is required for intestinal homeostasis, with disorders in this system leading to increased risk of onset or aggravated symptoms of various diseases, including allergy, inflammatory bowel disease, autoimmune disease, and metabolic syndrome (1)(2)(3)(4)(5)(6)(7). Many of these conditions involve excessive inflammation, indicating that regulation of inflammation is indispensable for the maintenance of the intestinal symbiotic system.…”

Pustular psoriasis responding to Probiotics – a new insight

“…The rationale of usage of such probiotics is furthered by its potential multipronged action. Though unclear the proposed mechanisms of action include modulation of immune response in the gut which can directly affect the development of inflammatory disease mechanisms in systemic sites of disease, such as the skin [7]. However, the mechanisms by which intestinal immune responses translate to systemic anti-inflammatory effects remain to be established.…”