Alcohol-associated intestinal dysbiosis impairs pulmonary host defense against Klebsiella pneumoniae

Dysbiotic drift and biopsychosocial medicine: how the microbiome links personal, public and planetary health

The emerging concept of planetary health emphasizes that the health of human civilization is intricately connected to the health of natural systems within the Earth’s biosphere; here, we focus on the rapidly progressing microbiome science - the microbiota-mental health research in particular - as a way to illustrate the pathways by which exposure to biodiversity supports health. Microbiome science is illuminating the ways in which stress, socioeconomic disadvantage and social polices interact with lifestyle and behaviour to influence the micro and macro-level biodiversity that otherwise mediates health. Although the unfolding microbiome and mental health research is dominated by optimism in biomedical solutions (e.g. probiotics, prebiotics), we focus on the upstream psychosocial and ecological factors implicated in dysbiosis; we connect grand scale biodiversity in the external environment with differences in human-associated microbiota, and, by extension, differences in immune function and mental outlook. We argue that the success of planetary health as a new concept will be strengthened by a more sophisticated understanding of the ways in which individuals develop emotional connections to nature (nature relatedness) and the social policies and practices which facilitate or inhibit the pro-environmental values that otherwise support personal, public and planetary health.

Diet, Gut Microbiota, and Vitamins D + A in Multiple Sclerosis

Central to the understanding of the relationships between diet, gut microbiota, and vitamins D and A in multiple sclerosis is low-grade inflammation, which is involved in all chronic inflammatory diseases and is influenced by each of the above effectors. We show that food components have either proinflammatory or anti-inflammatory effects and influence both the human metabolism (the "metabolome") and the composition of gut microbiota. Hypercaloric, high-animal-fat Western diets favor anabolism and change gut microbiota composition towards dysbiosis. Subsequent intestinal inflammation leads to leakage of the gut barrier, disruption of the blood-brain barrier, and neuroinflammation. Conversely, a vegetarian diet, rich in fiber, is coherent with gut eubiosis and a healthy condition. Vitamin D levels, mainly insufficient in a persistent low-grade inflammatory status, can be restored to optimal values only by administration of high amounts of cholecalciferol. At its optimal values (>30 ng/ml), vitamin D requires vitamin A for the binding to the vitamin D receptor and exert its anti-inflammatory action. Both vitamins must be supplied to the subjects lacking vitamin D. We conclude that nutrients, including the nondigestible dietary fibers, have a leading role in tackling the low-grade inflammation associated with chronic inflammatory diseases. Their action is mediated by gut microbiota and any microbial change induced by diet modifies host-microbe interactions in a consequent way, to improve the disease or worsen it.

The interaction between smoking, alcohol and the gut microbiome

The gastrointestinal microbiome is a complex echosystem that establishes a symbiotic, mutually beneficial relation with the host, being rather stable in health, but affected by age, drugs, diet, alcohol, and smoking. Alcohol and smoking contribute to changes in the stomach and affect H pylori-related disorders including the risk of gastric cancer. In the small intestine and in the colon alcohol causes depletion of bacteria with anti-inflammatory activity, eventually resulting in intestinal damage with "leaky gut". These changes contribute to hepatic damage in both alcoholic and non-alcoholic liver disease and have been associated with other disorders. Lactobacillus GG and A. muciniphila exert a protective effect in this setting. Smoking leads to modifications of the gut microbiome linked with a protective effect toward ulcerative colitis and deleterious for Crohn's disease. The exact cause-effect relation between alcohol and smoking and changes of the gastrointestinal microbiome needs further exploration with high throughput methodologies, and controlled studies are necessary to define the role of microbiome modulation on the immune response and systemic activation of pro-inflammatory pathways.