Role of Gut Microbes in Overall Health & Digestion
The gut is made up of over 100 trillion microorganisms, including bacteria, viruses, phages, yeast, and fungi. This is over 10x the number of human cells in the body! This collection of organisms is referred to as the gut microbiota. The gut microbiome refers to the microbes and all of their genetic material, which contains over 3.3 million genes!
We are still learning a ton about the gut microbiome and how the genetic material of microbes affects who we are. We are also still learning about the various strains of bacteria and their specific roles in the body, but we do know some general functions of the microbiota, listed below.
Defends against pathogens
Strengthens intestinal barrier
Optimizes nutrient absorption and utilization
Manufactures B Vitamins and Vitamin K
Regulates appetite and food intake
Regulates metabolism
Plays a role in immune system development and function
Modulates gene expression to determine which genes are activated
Plays a role in brain development, function, and health
The role of microbes in these functions is due to what they produce as they are metabolized. Gut microbes produce neurotransmitters, including gamma-Aminobutyric acid (GABA), serotonin, dopamine, and noradrenaline. These modulate brain function and behavior, including emotion and pain sensitivity. The microbiota also produces gut peptides, including leptin, ghrelin, and neuropeptide Y. These play a role in appetite, weight, circadian rhythms, and anxiety. Microbes also produce short-chain fatty acids (SCFAs), including butyrate, propionate, and acetate. SCFAs act as messengers that communicate to organs to regulate metabolism. They can also be used to fuel gut cells, strengthen the intestinal barrier, decrease inflammation, regulate immune cells, strengthen the blood brain barrier, affect gut-brain hormonal communication, and interact with nerve cells.
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Microbiome and IBS
When there is an abundance and variety of beneficial bacteria in the microbiome, all of these functions go smoothly and there are better health outcomes. When there is little diversity of bacteria, or negative bacteria are thriving, these functions will not be performed well and health could suffer. With IBS, one of the major causes that is considered is a change in the makeup and diversity of bacteria in the gut. So this is a big deal for those of us living with IBS and wanting positive health outcomes in the future.
Influencers of the Gut Microbiome
The microbiota composition starts in a small part in utero. Microbes have been identified in the amniotic fluid, umbilical cord, placenta, fetal membrane, and meconium of newborns. This is most likely influenced by the microbiota in the mother’s gut. The majority of microbiota composition happens at birth and in early childhood. Most colonization of microbes occurs as a baby passes through the birth canal, also influenced by the mother’s microbiome. For babies born via cesarean section, the major exposure to bacteria is from the hospital environment and the mother’s skin, which is still good but not as ideal. Breastfeeding also supplies the baby with bacteria to build up the microbiome, and provides prebiotics to strengthen beneficial bacteria so they can thrive.
During childhood, nutrition plays a major role in the development of the microbiome. A diet rich in plants supports healthy gut bacteria. A diet rich in processed foods and added sugar will lead to a less diverse microbiome and the increase of negative bacteria. Environment can also play a major role. Exposure to bacteria through playing outside or having pets in the home can actually lead to a healthier microbiome. Being too sterile from the overuse of antibacterial soaps and sanitizers can lead to a less diverse microbiome. Increased stress in childhood can also negatively affect the microbiome, and is another potential cause of IBS. Excessive antibiotic use can also be detrimental to a healthy microbiome.
In adulthood, the microbiome is already fully developed. However, diet and lifestyle can still alter the makeup of bacteria. A diet rich in plants, with adequate fiber intake, will promote more beneficial bacteria. In addition to diet, managing stress, spending time outdoors, and getting plenty of sleep can also help. The reverse of these habits can contribute to a less diverse, unhealthy microbiome.
For those with or without IBS, improving the healthy and diversity of the microbiome is essential for proper digestion and overall health. If you’re looking for guidance on how to improve your gut health, while also managing digestive symptoms, schedule a consult here to learn more!
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