Gut Microbiota and Microbiome: Digesting Research

Your unique Gut Club has 100 trillion active members

I think by now, we can all safely assume that most of us already know that we have beneficial bacteria present in our gastrointestinal tract (digestive tract). In this article, we’ll dive a little deeper into that topic but promise to keep things as simple and straightforward as possible.

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Gut microbiota refers to the different varieties of microorganisms that reside in a particular environment or body part. In this case, that would be your gut or gastrointestinal tract. Gut microbiota is sometimes used interchangeably with the term gut microbiome. Gut microbiome refers to the collection of genetic material of different microorganisms in your gut. Both terms can include bacteria, viruses, fungi, and other organisms with a single cell.

Various parts of your body, like skin, mouth, lungs, and gut, contain different sets of microbiome and microbiota. In this article, we’ll focus on your gut, specifically the beneficial bacteria residing in it. And for simplicity, we’ll use the term gut microbiota.

Gut Microbiota – Your Very Own Gut Club! Who are the members of a HEALTHY Gut Microbiota?

Your gut microbiota is like an exclusive social club with trillions of active members. It’s your very own Gut Club. All social clubs have clubhouses, and in this case, your gastrointestinal tract is the clubhouse. Your Gut Club also has several committees (bacterial groups), members (specific bacteria), and occasional uninvited guests (harmful or pathogenic bacteria).

Healthy gut microbiota is predominantly composed of two big groups of bacteria, namely, the Firmicutes and the Bacteroidetes. They’re like the central committees in your gut club where top players and decision-makers belong. It’s estimated that there’s an average of 50 bacterial groups detected in each person, with each bacterial group having as many as 1,000 members. Yeah, it’s really a big club.

Outstanding committee members (specific bacteria) of your gut club include the following:

Sixty per cent of all the bacteria living in your gut belong to the bacterial groups Firmicutes and Bacteroidetes groups. It’s a fact that an imbalance in gut microbial populations (called dysbiosis) can be linked to different medical conditions. Whether these conditions cause the imbalance or vice versa, is another topic of discussion. So, for now, we’ll settle with the terms linked, associated, or related to the development or presence of such medical conditions.

How did all the beneficial bacteria get inside your gut? Who brought them there in the first place?

When you are born, your gastrointestinal tract is believed to contain very few bacteria. Some scientists consider your gut to be sterile, like a blank canvas. This quickly changes right after you are delivered. If a baby is delivered vaginally, the gut microbiota of the baby shows similar bacterial populations with the mother’s vaginal microbiota. Babies who are delivered via caesarean section will show fewer bacterial numbers.

During infancy, the composition of microorganisms is closely related to that of his or her mothers. This signifies kinship as a predominant factor in the population of gut microorganisms during the first year of life.
On the road to becoming an adult, the gastrointestinal tract undergoes remarkable changes. It’s expected that the gut microbiota remains reasonably stable. This means that the top players, namely the Bacteroidetes and Firmicutes bacterial groups, are still the dominant groups in the gut. It’s also worth pointing out that the bacterial groups are unevenly distributed along your gastrointestinal tract, so don’t be surprised if samples yield different members from different groups. It’s during this time that your unique Gut Club starts accepting new members and forms new committees.

What are the functions of gut microbiota?

Optimises metabolism; yours, and theirs (bacteria). You’ll be surprised that your gut bacteria can perform the following metabolic functions:
- Make the vitamins: thiamine, folate, riboflavin, biotin, pantothenic acid, and vitamin K.
- Produce all nonessential and essential amino acids.
- Conduct the processing of bile.
- Breakdown and use nondigestible carbohydrates: polysaccharides (resistant starch, cellulose, hemicellulose, pectins, and gums), oligosaccharides, and unabsorbed sugars and alcohols from your diet.
In essence, these beneficial bacteria squeeze, process, and recover every bit of available substrate, energy, and nutrients for your growth and their proliferation. These are all reabsorbed in different parts of your intestines for further use. They’re like Santa’s elves, very efficient and reliable.
Rouses your body’s immune system, especially its virus-fighting capabilities. Based on an article published in the scientific journal Cell in November 2020, researchers discovered that a particular bacteria (Bacteroides fragilis) produces a molecule that stimulates mice immune cells into action, which aids in eliminating certain viruses. They did this under laboratory conditions, and they successfully demonstrated it when immune cells from the mice fought off an infection brought about by Influenza A virus. Mind you, Bacteroides fragilis, is just one of the numerous possible candidates that could help us fight off viral infections. Always consider the other members of your Gut Club.
Muscles out harmful bacteria. Your healthy gut microbiota competes with harmful or disease-causing bacteria through what is known as a barrier effect. On the surface of cells lining your gastrointestinal tract are receptors to which some of your gut microbiota attach to. Harmful bacteria also adhere to these receptors. Your gut microbiota, through sheer numbers, simply outcompete and form a barrier against harmful bacteria by attaching to these sites and consuming all the nutrients in the immediate environment. These harmful bacteria represent uninvited guests or gate crashers at the parties of your Gut Club.
Helps in the prevention of allergies. Young children with allergies have a less diversified gut microbiota compared to those who don’t have allergies. It’s hypothesised that your gut microbiota stimulates your immune system and trains it to respond adequately (not overreact or underreact). If there’s an imbalance in your gut microbiota in early life, it can lead to an inadequately trained immune system. This immune system can be overly sensitive even to some members of your gut microbiota.
Reinforces the gut-brain connection. Your digestive system and brain have their two-way communication system called the gut-brain axis. It consists of immunological, hormonal, and neural messaging between the two. Your stress levels influence the movement of your bowel, secretion of enzymes from your digestive tract, and mucin production. These three alter the composition and metabolism of gut microbiota at different segments of your gastrointestinal tract. Your gut microbiota also communicates with your nervous system by providing feedback to your brain to modulate how you react to stress.

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There’s a lot to discuss and digest when it comes to your gut microbiota. The interest and research in the gut microbiome (all that genetic material), in particular, has flourished in recent years. It’s still in the preliminary stage, but studies have shown their great potential in discovering and revolutionising the cause of diseases and treatments. Let’s all stay tuned.

We have an article about tips on how you can support your gut microbiota, click here.