BACTERIA AND VIRUSES AND FUNGI, OH MY

THE GUT MICROBIOME

By LINDSAY ROMANO ALLISON GENTRY

What th gut m r b m ? Did you know that the number of microbial cells on your body is 10 times the amount of cells you have? With over 5,000 different species, the human microbiome has become a topic of significant interest in recent years. It is becoming increasingly apparent that the tiny microorganisms living in and on humans play a big part in many processes. These microorganisms, or microbes, include fungi, viruses, and bacteria. Many different species of these taxa exist together in various locations around the body. They participate in a symbiotic relationship with the individual, meaning that there are mutual benefits for both parties. Like fingerprints, each person’s microbiome is unique, there is a particular set of species present that will complement each other while also fitting the needs of the host. If they do not, they will be overrun by species that are better suited for the individual. In the womb, we have little to no microbiome, and once babies are born through natural birth, they are first colonized by the microbiota of their mother. The newly established population of microbes will continue to grow and diversify based on the diet, genetic disposition, and environmental factors as they age.

There are many different microbiomes that exist all over the body including your skin, mouth, and gut. All of these are important and function to keep us healthy and aid in routine body processes. The gut microbiome is particularly interesting because it is strongly influenced by the diet. An individual’s diet determines what microorganisms are introduced into the body and determines what kind of nutrition is provided to them. This helps shape the microbiome by helping certain species flourish while others may not be as successful.

The different types of microorganisms that live in the gut make up the majority of the microbiome. Bacteria are introduced through food but specifically probiotics, which contain live cultures of bacteria, colonize the gut. Fungi take up only a small percentage of the microbiome but are still important for the biodiversity and effectiveness of gut health. They are usually consumed and then colonize the stomach and intestine area. Viruses are different because they require a host for survival, so they live within the bacterial populations. The viruses in the gut are different than the harmful infectious viruses that we are more familiar with. The gut contains more stable populations of viruses that reside in their host bacteria in a symbiotic relationship. This kind of relationship also exists between other microbes and with the cells of the individual to maintain a fruitful environment.

H ar th m r rga m h lpful? The microbes in your gut are an essential part of your digestive system, aiding in the breakdown of food during routine digestion. They live off of consumed food as it travels through the digestive

Esson, Alex. "Ohio State Scientists Explain How Gut Microbes Change after Spinal Cord Injury." Front Line Genomics, October 26, 2016. http://www.frontlinegenomics.com/ press-release/7983/gut-microbes-changespinal-cord-injury/.

system, specifically in the stomach and intestines. The microbes break down things like fiber through fermentation to synthesize shortchain fatty acids. This process is beneficial to the individual because these microbes contain enzymes not found in human somatic cells that are capable of digesting soluble fibers. The production of fatty acids helps support digestion by lowering pH, creating a more acidic environment. This process helps further the breakdown and absorption of other food products in the digestive tract. These molecules are also involved in maintaining energy homeostasis and encouraging the growth of other bacteria.

The gut microbiome is also important for disease prevention. Diversity within these microorganisms is very important because it makes the gut more robust against harmful bacteria and viruses that might be consumed. There have been many studies showing that having a lack of certain gut microbes is associated with diseases like inflammatory bowel disease, diabetes, and obesity. This is due to the fact that many products released by the bacteria and fungi have effects on hormone regulation, glucose regulation, and inflammation. These are all important factors in maintaining homeostasis, so dysregulation can increase the susceptibility of an individual to diseases based on poor food choices.

H up rf h lp ma ta gut h alth? Some popular items praised for improving microbiome health include kombucha, yogurt, and whole grains. These foods work in different ways to improve the health of your gut. For example, kombucha is a fermented drink that consists of a mixture of tea, sugar, yeast, and bacteria. The yeast and bacteria create a symbiotic colony that ferment the drink by metabolizing the sugar and creating a byproduct of alcohol, acid, and gas. This process is what makes the drink iconic fizz and vinegary taste. Kombucha does contain probiotics which can help improve gut health, but there is still research being done to determine if it has any effects on overall health. Other popular food items known for promoting digestive health include yogurt and kefir. Both of these are dairy products that contain bacteria that ferment sugars, however, not all yogurts have probiotic bacteria that are beneficial for helping your gut. Only certain strains of bacteria are beneficial for gut health, and others will be unable to cooperate with the gut and will be digested. So, when looking for a yogurt to help replenish your gut bacteria make sure to check that it is marked as probiotic. Whole grains are important because they are prebiotics that gut microbes need to consume to flourish. Prebiotics are generally carbohydrates such as fiber and oligosaccharides, which

are composed of simple sugars bonded together. Whole grains are beneficial because they have higher levels of fiber than refined grains. Fiber is a food source for the bacteria and fungi that reside in the gut, but it is important not to ingest an overabundance of these foods since it could lead to a reduction in microbial diversity. This would occur when certain species overpower others that may not depend on fiber as much. Although all of these foods products are good ways to help improve your gut microbiome, moderation is important to keep balance and diversity. With the increasing interest in how the gut microbiome works with the body to help keep us healthy, there is new research being conducted all the time. There are more novel studies looking into fungi population, as most research has focused on the bacterial populations. It has already been found that fungi populations vary significantly between individuals and scientists are working to determine why that might be. In general, it seems the message is clear – make sure to keep moderation in your diet and don’t forget about all of those microorganisms that work every day to sustaining your health.

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