Gut microbiome: What it is and what does it do?

When you eat every day, you are technically feeding trillions of bacteria, viruses and fungi living in your gut. No, they are not a bad thing since it is natural for your digestive system to have microscopic living things. In fact, these microorganisms are called the gut microbiome. 

Scientists used to have little knowledge about the communities of microbes that altogether make up the gut microbiota or also known as your gut microbiome. However, with continuous research, they found out that the gut microbiome is one gateway to healthy well-being. 

What is the gut microbiome? 

Digging deep into the gut microbiome, there are microorganisms living inside your gut, and they are called microbes. Your microbes can be found in a ‘pocket’ of your large intestine that is called the cecum – referring to a pouch that forms the first part of the large intestine. The microbes exist in trillions as part of your gut microbiome. Aside from its primary location inside your intestines, microbes can also be found on your skin. 

Bacteria, viruses, fungi and other microscopic living things live inside you, particularly in your digestive system. Many studies try to find out the purpose of them in your gut. However, the most studied research is on the function of bacteria in the gut. In fact, it was found that the number of bacterial cells in your body is much more than human cells. There are about 40 trillion bacterial cells and 30 trillion human cells in your body [1]. 

Furthermore, bacteria live inside your gut microbiome in varying species for up to 1,000 kinds, and each of them has a distinct role in your body. In totality, the microbes in your body may weigh up to 2 to 5 pounds or 1 to 2 kg – similar to your brain’s weight. Think gut microbiome as an extra organ composed of trillions of microbes that function in bettering your gut health [2]. 

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Different microbiomes in the body

Numerous communities of microbes exist in your body, and each creates its own microbiome. The gut microbiome is basically found in your digestive system, where the largest numbers of microbe communities are found in small and large intestines. It plays a vital role in digestion and maintaining your immune system healthy. Whenever there are disturbances in your gut microbiome, you may experience health issues, such as obesity, diabetes, eczema, celiac diseases, inflammatory bowel disease and psoriatic arthritis.

There are different microbiomes in your body, such as skin, oral and reproductive microbiomes. All these are categorised based on the placement of the microbiomes. 

For the skin, microbiomes exist and interact with your body’s immune system and impact your dermatological health. These are friendly bacteria, fungi and viruses that work on your body to prevent pathogen invasion and infections [3].

On the other hand, the oral microbiome hosts the second largest microbiome after your gut. It has over 700 species of bacteria that help in digestion, keeping oral health and overall wellness. 

Reproductive microbiomes generally exist in the female reproductive organs, and they play an important role in reproductive changes as a result of several factors, such as age, menstruation and pregnancy. 

Gut microbiome and your health

The gut microbiome is generally important in human development, immunity and nutrition. There are good bacteria inside your body that are health-beneficial and not entirely considered invaders. When you have a dysfunctional microbiome, you may experience autoimmune diseases, including diabetes, rheumatoid arthritis, muscular dystrophy, multiple sclerosis and fibromyalgia. 

Moreover, autoimmune diseases are not caused by DNA inheritance but by inheriting your family’s microbiome. Examples are the following: 

  • Obese and lean twins have acquired two different microbiomes from their biological parents. The obese twins are found to get a lower diversity of bacteria and higher levels of enzymes, which means that they are more efficient at digesting food and harvesting calories. Also obesity has also been linked to a poor combination of gut microbes. 
  • Type 1 diabetes refers to an autoimmune disease that is linked with a less diverse gut microbiome, and it was also found that gut bacteria have a role in developing diabetes. 
  • Your dogs may reduce their immune response to allergens and other asthma triggers through the dust in your home. It can change the composition of their gut microbiome. 

While the gut microbiome is the collected genomes from all microscopic living things inside your gut, the microbiota is the term to refer to those microorganisms. The gut microbiota stimulates the immune system, breaks down possible toxic food compounds and synthesises vitamins and amino acids, like B vitamins and vitamin K [4]. 

The upper part of your small intestine can quickly absorb sugars, particularly table sugar and lactose (milk sugar). However, the much more complex ones, like starches and fibres can’t be easily digested. With the existence of microbiota, your gut can easily break down its compounds with its digestive enzymes. 

When your microbiota is healthy, you can be protected from pathogenic organisms that may enter your body, most essentially when drinking or eating contaminated water or food.

Some significant bacteria found in the human gut are Prevotella, Ruminococcus, Bacteroides and Firmicutes. In the colon, there are the anaerobic bacteria Peptostreptococcus, Bifidobacterium, Lactobacillus and Clostridium. This microbiota in the gut can prevent the overgrowth of harmful bacteria by fighting for nutrients and attachment sites to the mucous membranes of the gut – referring to the main site of immune activity and antimicrobial protein production. 

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Microbiota and the role of probiotics

Your gut has probiotics as part of your microbiome. You get them from supplement pills that have live active bacteria and foods which contain microbiota. A professor from the Harvard Chan School of Public Health and Harvard Medical School, Dr Allan Walker, suggests that probiotic supplements can help sustain your body’s probiotic counts. According to him, probiotics can be best effective at both ends of the age spectrum, as during that time, your microbes are not as robust as they normally are. And with probiotics, you can broadly influence the bacterial colonisation process more effectively [5]. 

Furthermore, Dr Walker identified certain situations where your body is under stress, and probiotics could be helpful. Some of these are the reduction of the severity of diarrhoea after exposure to pathogens and the replenishing of normal bacteria in the intestine after the intake of antibiotics. He also added that these circumstances are where there is a disruption of balance within the intestine. 

Symptoms of an unhealthy gut

How would you know if you have a healthy gut microbiome? You will definitely see and feel the signs in your digestive system, such as the following: 

  • Weight gain and obesity – Research suggests that there is a link between obesity and disturbances in the gut microbiome. It has been found that manipulating the gut microbiome can be a way to facilitate weight loss and prevent obesity. 
  • Gastrointestinal discomfort – Whenever there is an imbalance, you may experience gastrointestinal discomfort frequently, which is characterised by an upset stomach from gas, bloating, abdominal pain, diarrhoea, constipation and signs of irritable bowel syndrome (IBS), in fact, imbalances in your gut microbiome is a huge factor in having IBS for some patients. 
  • Fatigue chronic fatigue syndrome – this is a condition characterised by extreme fatigue that can be experienced for at least six months. This can be linked to an imbalance in your gut microbiome. According to research studies, nearly half of patients who suffer from chronic fatigue syndrome also have IBS. 
  • Autoimmune diseasesBacteroides fragilis is one particular kind of bacteria that is found in the gut. It produces an essential protein that can trigger the onset of certain autoimmune diseases, such as ulcerative colitis, rheumatoid arthritis and multiple sclerosis.
  • Skin conditions – The imbalances in your gut microbiome can contribute to several skin disorders, such as acne, atopic dermatitis, eczema and psoriasis. Allergies can also occur when there is a gut imbalance. An unhealthy gut microbiome can be an important factor in allergies like food allergies and skin allergies. 
  • Mood disorders – It is found that there is a link between gut health and the brain. Any disturbances in the gut microbiome and inflammation in the central nervous system can cause mood disorders or, worse, depression and anxiety. 
  • Migraines – Some studies also found that gut imbalances can cause migraines. Although the scientific connection is not yet fully discovered, it is still considered one good factor contributing to migraines [6]. 

Achieving a healthy gut 

In our day-to-day lives, we go to different environments with varying combinations of habits and surroundings. Hence, we acquired a set of different kinds of the gut microbiome, a unique bacterial fingerprint that only you possess. It is up to you how you would manage to get your microbiome to a healthy state or keep it on track. Ideally, a healthy gut must have a strong barrier that can deal with all the content of your gut, such as microbiota, undigested food particles and toxins, from escaping into the bloodstream. But, of course, the obvious sign is not having to experience any gut issues. 

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The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.