EARLY LIFE DETERMINANTS AND GENETIC MODIFIERS OF THE HUMAN GUT MICROBIOTA: IMPLICATIONS FOR DYSBIOSIS AND DISEASE

Abstract

The gut microbiome comprises trillions of bacteria, viruses, fungi, and archaea. The genes of these microorganisms, collectively referred to as the gut microbiota, are crucial for digestion, xenobiotic metabolism, and the regulation of both innate and adaptive immune responses. This relationship is maintained through a continuous biochemical exchange of proteins, peptides, and metabolites with the host. However, factors such as ageing, chronic stress, poor diet, antibiotics, and underlying illnesses can disrupt this essential balance, leading to gut dysbiosis. Dysbiosis is characterised by reduced diversity and alterations in the abundance of key bacterial taxa. It is not only linked to local digestive symptoms like bloating, diarrhoea, and constipation but also to systemic conditions such as fatigue, immunological imbalance, and metabolic abnormalities. Dysbiosis is now closely associated with the aetiology of inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), obesity, diabetes, cancer, cardiovascular diseases, and neurological disorders. Systemic approaches to address dysbiosis include probiotics, prebiotics, dietary modification, and intestinal microbiome transplantation (IMT), which is particularly helpful for recurrent Clostridium difficile infections.