Over the past century, our understanding of microbiology and the gut microbiome has undergone a significant transformation. What was once a relatively obscure field is now one of the cornerstones of modern biomedical research. Indeed, scientists have discovered that the trillions of microorganisms that live in a symbiotic relationship with our body play a number of key roles in the function of our digestive system and other aspects of health. More importantly, understanding how to improve the health of our intestinal bacteria may yield a wide range of health benefits.

What Is the Gut Microbiome?

The term gut microbiome refers to the complex and diverse community of microorganisms that inhabit the digestive tract—more specifically the small intestine and large intestine. The largest category of microbes is anaerobic bacteria, but the community also includes viruses, fungi, and other single-celled organisms. It is estimated that a given microbiome contains anywhere between 300-1000 different species of microorganism. This means that each individual has their own unique collection of intestinal bacteria that can similarly impact health in unique ways.

How Do Gut Microbiota Impact Overall Health?

In the early days of research into the gut microbiome, it was assumed that the various types of bacteria were mostly related to gastrointestinal functions. More recent research has shown, however, that the microbiome is connected to other aspects of health via the gut-brain axis, a bidirectional communication network that connects the enteric nervous system with the central nervous system. This axis facilitates communication through neural, hormonal, and immunological pathways and is thought to impact overall health in numerous ways:

  • Digestive health: One of the most important roles of the microbiome is related to maintaining the mucosa that lines the wall of the digestive tract. A healthy and balanced microbiome can help maintain bowel regularity while an imbalance can lead to gastrointestinal symptoms like diarrhea, constipation, and bloating or disorders like irritable bowel syndrome or SIBO (small intestinal bacterial overgrowth).
  • Immune system: The gut microbiome also plays a role in helping the immune system distinguish between harmful pathogens and beneficial bacteria. These helpful bacteria can also prevent pathogens from being able to multiply because they essentially outcompete the pathogens for resources.
  • Inflammation: Inflammation is part of a normal immune response to potentially harmful stimuli, but an imbalance in the gut microbiome (dysbiosis) can cause abnormal inflammatory responses that can eventually become chronic. Maintaining proper gut health, then, can reduce inflammation and may even improve or reduce the risks of developing health conditions like inflammatory bowel disease (especially Crohn's disease and ulcerative colitis), heart disease, or various autoimmune diseases.
  • Metabolism: While most of the nutrients the body needs are absorbed from the small intestine, the gut microbiome is also involved in breaking down complex carbohydrates and fermenting dietary fibers that human enzymes cannot digest. Some of these processes can even produce short-chain fatty acids (SCFAs) and other metabolites that can be used for energy.
  • Compound synthesis: Some gut bacteria (especially bifidobacterium) are able to synthesize some of the essential nutrients our cells need for regular function like vitamin K and vitamin B12.
  • Weight management: Recent research has shown that a healthy and balanced gut microbiota seems to improve the amount of energy that can be absorbed from the foods we eat. An imbalance, on the other hand, can lead to increased hunger, insulin sensitivity, weight gain, and obesity; such an imbalance may also be a key factor in weight-related conditions like type 2 diabetes and metabolic syndrome.

Tips for How to Improve the Microbiome

Given how central the gut microbiome is to so many different areas of health, it’s important to keep it healthy and in balance. The methods for achieving such a balance depend on the microbiome’s current state, but there are several tips for how to improve it:

  • Fiber: One of the most effective ways to maintain good gut health is to follow a diet that is rich in dietary fiber. In addition to providing bulk for stool and promoting regular bowel movements, fiber is one of the resources that allows gut microbiota to thrive.
  • Diverse foods: Eating a variety of foods from different food groups introduces different nutrients and supports a diverse microbiome. A healthy diet should include a diverse selection of fruits, vegetables, whole grains, legumes, and nuts.
  • Fermented foods: Fermentation is a process where microorganisms like bacteria or yeast break down organic compounds into simpler substances. In the colon in particular, the gut microbiota ferment otherwise indigestible fiber and produce several important compounds like SCFAs and amino acids that form proteins.
  • Probiotics: Probiotics are living microorganisms that are believed to be beneficial to the gut microbiome by promoting a healthy gut environment. While more research into probiotic supplements is needed, there is evidence that probiotics from fermented foods are the best source. Examples of probiotic foods include yogurt, sauerkraut, kimchi, tempeh, and kefir.
  • Prebiotics: Though the words are similar, prebiotics are quite different from probiotics; prebiotics are essentially any compounds that promote the growth or activity of beneficial bacteria like the gut microbiota. Unlike probiotics, which are live microorganisms, prebiotics are compounds that serve as food for these beneficial bacteria.
  • Physical activity: Exercise, or virtually any kind of regular physical activity, is beneficial for health in a number of ways. In the microbiome, physical activity can improve nutrient synthesis and increase the quantity and diversity of helpful bacteria.
  • Adequate sleep: Adequate sleep is also important for overall health, but lack of adequate sleep can negatively impact the health of the microbiome. Lack of sleep can also worsen some of the other microbiota problems noted here.
  • Fecal transplant: In cases where the imbalance of bacteria in the microbiome is especially severe, minor adjustments to diet and physical activity levels may not be sufficient. One way to restore or enhance the diversity of a person’s gut microbiome is through a fecal microbiota transplantation (FMT). Also known simply as a fecal transplant, this medical procedure involves transferring fecal material from a healthy donor to a recipient. As a relatively new procedure, however, more study is needed to investigate the long-term effects.

Contact Cary Gastroenterology

Researchers will continue to look at the impact of the gut microbiome on human health, but it’s already clear that the connection is significant. But even if your gut health isn’t the best right now, there are many different ways to improve the situation. At Cary Gastro, we are passionate about helping our patients maintain excellent digestive health that ensures high quality of life. If you’d like to speak with a gastroenterologist about your gut health or any kind of gastrointestinal symptoms, please contact us today to request an appointment.