What if we were told that we are more microbial than human? Well, it’s true! That human we see in the mirror is made up of more microbes than human cells. These microbes in our body outnumber our human cells.
Human “The Slaves of Bugs”
What if we were told that we are more microbial than human? Well, it’s true! That human we see in the mirror is made up of more microbes than human cells. These microbes in our body outnumber our human cells. And not just that, the microbial genes also outnumber our genes by 100 to 1. In every nook and corner of our body, and especially in our guts, dwell the microbiome: 100 trillion microbes of several hundred species that bears 3 million non-human genes. Yes, we are not just humans, we are.
Microbes are part of our evolution – humans have evolved to live with microbes for millions of years. From making our earth suitable for life by producing oxygen, to solving the unprecedented challenges that humans are facing today, microbes play a more crucial role in the earth’s ecosystem than we can imagine. We all know what microbes are – they include viruses, fungi, bacteria and a number of other microscopic life forms that are too small to be seen with our naked eye. They belong on and in our bodies – these microbes aren’t just along here for the ride, they are there for a reason. Humans have a mutual relationship with them — we provide them a place to live, and they help keep us alive.
Why our health is in the hands of the microbes?
The human microbiome is considered as a virtual human organ that is essential for our survival. They play a very important role in human health and in human disease as well, impacting almost every aspect of our lives – our immunity, the way we digest our food, our body odor, our weight, and even our mental health.
Living inside of our gut are about 300-500 different kinds of bacteria that contain nearly two million genes. When they are paired with other micro-organisms like viruses and fungi, they make what is known as the microbiome. Without the gut microbiome, it would be very difficult for us to survive. The gut microbiome begins to affect our body right from the moment we are born, while we pass through our mother’s birth canal.
Should we consider microbes as our friends or foe? Most of the microbes live a harmonious existence with our cells – 99.99% of bacteria helpful to promote health, but diseases can occur when this balance is disrupted or when our immune system is weakened. Microbes extract nutrients and vitamins we need to survive, they can also transfer genetic information between each other and through this, antibiotic resistance is spread among the microbial population.
Important functions of gut microbes
1. Microbiome helps in digesting our food
We cannot digest most of the food we eat without the beneficial bacteria in our gut. Gut bacteria include Lactobacillus – the bacteria which is commonly used in probiotic foods such as yogurt, dosa batter, cheese, etc. and E. coli bacteria. These bacteria produce enzymes that help us digest polysaccharides (healthy, complex sugars found in plants). About a third of all bacteria in our gut are members of the Bacteroides species which play a key role in helping us digest plant food. Gut bacteria are also responsible for providing us with vitamin B, Vitamin K, and short chain fatty acids. Hence, they help influence the nutritional value of the food we eat.
2. Microbiome helps influence our mental health
Did you know that our gut is lined with more than 100 million nerve cells? Yes, we have brain cells in our large intestines too! This is why microbes that set up home in our gut also impacts our mental health. Our brain and the gut are connected via the vagus nerve, enteric nervous system, and the gut-brain axis. The gut microbiota actually interact with our central nervous system to regulate brain chemistry. That’s right, our gut bacteria can actually affect our response to stress, anxiety, and even our memory. Studies have shown that our gut microbes can influence the serotonin and dopamine production. Serotonin not only makes you feel happy, but also helps in digestion. In fact, 90% of the serotonin can be found in our gut.
3. Microbiome helps boost our immune system
One of the most important functions of the gut bacteria is to boost the immune system. Our immune system is the main link between our gut microbes and their influence on our health and disease. Gut bacteria trains our immune system from the moment we are born. They teach our immune systems how to recognize dangerous invaders and even help produce anti-inflammatory chemicals and compounds to fight off the microbes that make us sick. This hence keeps our body from attacking the friendly gut microbiome needed for digestion.
4. Microbiome helps promote healthy skin
Our skin is a home to a large number of microbes. Just like our gut, our skin can benefit from the right balance of microbes. Healthy microbes help protect our skin from bacterial and fungal infection by preventing the overgrowth of pathogenic microorganisms. It keeps inflammation in check, promotes wound healing and can also convert skin oils into natural moisturizers that keep our skin healthy.
5. Microbiome helps protect from toxins
Just as we breathe in oxygen and release carbon dioxide, microbiome in and on our bodies also helps take in toxins and spare us from their dangerous effects. Bifidobacteria prevents the toxins from passing through the intestinal wall and into your bloodstream.
Microbiota is also responsible for
- ontrolling metabolism and nutrient storage
- Decreasing inflammation
- Producing antimicrobials
- Maintaining tissue integrity
- Controlling blood pressure
Thanks to the microbiome – we are not just humans, we are super organisms!
Where do our gut microbes come from?
We may be wondering how these tiny creatures living in our gastrointestinal tract get their way in? Did we just pick them up from our surroundings? Maybe partly, but it is much more complicated than that. It is still a little bit controversial but for the most part, it is said that we are born with a sterile gut which picks up microbes on our journey through our mother’s vagina.
As soon as the mother’s amniotic sac is broken, we are exposed to bacteria. If we are born through vaginal delivery, we get a dose of our microbes from the birth canal, but if born by C-section, our first dose is from the skin of our caretakers. Research have shown that these differences could be one of the reasons why babies born by caesarean section have a higher risk of conditions including asthma and type 1 diabetes.
Once we emerge fully into the world, we’re quickly exposed to a large number of microbes—from skin and breastmilk, and from bacteria in the place of our birth, such as the hospital. But as we age, our environment, our diet, the drugs we take, stress, etc. continue to play a role, meaning our microbiome can change throughout our lifetime.
factors influencing the gut microbial diversity
1. Mode of delivery
Mode of delivery is considered the first and most important influential factor on our gut microbial development. Vaginal delivery or C-section delivery can produce important differences in the composition of the community of our gut microbes. Birth by C-section have shown adverse effects on immune development, allergies, inflammatory disorders and infections than those born through normal delivery.
2. Breastfeeding or formula feeding
The human-microbiota relationship is connected to breastfeeding. Breast feeding increases the colonization by some healthy bacteria, such as the Lactobacilli and Bifidobacteria. Breast milk, for example, contains oligosaccharides, a type of complex carbohydrates which acts asthe main food for gut bacteria. This bacteria contribute to have a balanced bacterial community that can train the immune system. After the weaning, the composition of gut microbes in babies change, making it more diverse. Research have shown that it is important to follow a diet rich in fiber to nourish beneficial bacteria.
The exposure to antibiotics have been proven to be one of the major causes of gut microbiota imbalances. It is also known now that imbalances are linked to diverse health problems. There is a solid evidence that the maternal intake of antibiotics during pregnancy can increases the risk of allergies in newborn babies – like the antibiotic during the first month of human life has been associated with cow’s milk allergy later on.
Environmental factors shape the diversity of microbes. It is said that children in the tribal region have 3 fold diversity than children born in the urban areas. This explains the hygiene hypothesis: how being too clean might be making us sick. The idea is that for many children in the wealthy world, a lack of exposure to bacteria, viruses, and allergens prevent the normal development of the immune system, thereby increasing the chance of disorders within this system. Urban children have 10 fold higher incidence of allergy and asthma than rural children. Likewise children from developed nation are at higher risk of developing milk and nuts allergy than children in the under developed or developing nations. This is called the hygiene hypothesis.
The role our gut microbiota plays is central to our body’s operation, which is why it is very essential to maintain good gut health. As the saying goes “you are what you eat” – maintaining a healthy microbiome is all about our diet. Eating a diverse diet rich in complex carbohydrates, fiber, probiotics, and prebiotics can lead to diverse microbiota, which is very beneficial for your health.
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