What is Microbiota?

The unseen giant structure, microbiota, is one of the most popular and intriguing topics in the medical world today. The number of microorganisms within this structure reaches 100 trillion in each of us. Therefore, the effects of such a crowded structure on our health, its relationship with diseases, have become one of the most researched subjects in modern medicine. We wanted to examine this topic closely and take a closer look at this microscopic community of organisms in our bodies. Prof. Dr. Melih Özel, a Gastroenterologist at Anadolu Medical Center, shared important information on the subject...

The scientific community has revealed through many studies that the trillions of harmless microorganisms already present in the human body are linked to diseases and chronic conditions. For instance, there are studies on its relationship with the increasingly common obesity. Of course, the available data is still quite limited. Nevertheless, it appears that the microbiologists of today and the near future will dedicate much more effort to studying all the microorganisms in our bodies and investigating their potential links to diseases. Thanks to today's technologies, the genetic sequences in the cells of every living organism can now be read very quickly. The human genome, initially consisting of 3x 10^9 base pairs, was sequenced, and now the genetic sequences of any microbe can be easily and cheaply read. It is easy to distinguish which gene belongs to humans and which one belongs to another organism or microbe. As a result, for example, the diversity of microbes in the human gut— which contains many microbes— the ratios of these microbes, the differences between sick and healthy individuals, and even connections between obese and non-obese, or autistic and non-autistic individuals are now being uncovered and compared more easily. In simple terms, the microbes in the gut content (feces) can now be obtained from a small sample, and all the DNA/RNA found there can be quickly "read" in special devices and rapidly reported. However, despite all this, as mentioned, the relationship between microbiota and diseases is still in its early stages. While there are promising results for the future, it is still too early to draw conclusions based on the available data.

We should certainly be aware that this is a very hot topic, but it is also important to highlight certain points that should not be exaggerated. There is a significant theoretical gap in the medical field. We are talking about a "living" microenvironment that is affected and altered by dozens of different parameters, such as each individual’s genetic inheritance, family lifestyle and eating habits, environment, and medications used, which make it unique for every person. However, looking at ongoing studies and their results, we can expect serious developments in the near future regarding the role and effects of the human gut microbiota in explaining the underlying causes and mechanisms of diseases and diversifying treatment options.

10 Times More Than Our Own Cell Count!

In short, we can define microbiota as the total of microorganisms (bacteria, fungi, viruses, and protozoa) living in our body that are not human cells. We know that this crowded community of living organisms, which lives with us and numbers in the trillions, has a total population of over 100 trillion. If we also mention that their total weight constitutes about 2-3% of our body weight, we can imagine how vast a structure we are dealing with. Another surprising fact is that the number of these cells that make up our microbiota is 10 times greater than the number of our own cells.

Is Microbiota Our "Second Brain"?

It is not accurate to define the relationship between microbiota and humans using some "cliché" terms. There is no doubt that the human intestine has its own unique nervous system. In fact, considering that the gut functions independently and is affected by changes within it, we could even say that it has its own brain. However, we should not confuse the intestinal nervous system with the microbiota. Therefore, calling the microbiota "our second brain" is not a correct usage. The way microbiota and the human body coexist is actually a form of symbiotic living. It is a life form where both parties support and benefit from each other. The total of organisms within a specific ecosystem (for example, the shared human and microbial ecosystem) is called Holobiont (also referred to as "superorganism"). In summary, it is a way of life sustained through mutual interaction in the human body!

Why is Microbiota Important for Our Health?

This community of beneficial microbes living inside us is of great importance in maintaining body functions and overall health. Just like fingerprints, each of our microbiota has a unique structure. However, they are located in the same places in all bodies. Every microorganism in the microbiota lives in areas of our body suitable for its reproduction. These areas include our skin, oral cavity, respiratory system, genital system, urinary system, and of course, our digestive system. It is worth emphasizing that we have a dense microbiota content in our small and large intestines, although there are fewer in our stomach. The human gut microbiota plays important roles in many bodily functions, including digestion of food, supporting the immune system, synthesizing and biologically modifying certain vitamins, maintaining healthy intestinal functions, preventing inflammatory changes (inflammation), maintaining ideal body weight, brain function, certain cardiovascular diseases, and mental health.

"All Diseases Begin in the Gut"

Hippocrates, considered the father of modern medicine, was right when he said, "All diseases begin in the gut" about 2,000 years ago. Today's modern medicine agrees with this view. Scientific studies conducted today provide clues that problems related to the human gut microbiota may play a role in many diseases. The results of these studies suggest that seemingly unrelated diseases might be caused by changes in the gut microbiota. Although the cause-and-effect relationships are not yet clearly established, and no definitive data has been obtained to prove these ideas, we can say that the health of our gut affects all body systems.

The Relationship Between Microbiota and Diseases

The medical world has made significant progress, despite some gaps in knowledge, particularly regarding the relationship between changes in the digestive system microbiota and certain diseases. The activities of this microbial structure show significant variation in relation to human health across different human populations. The gut microbiota has a vast and diverse functional repertoire, and it is no surprise that it has become the focus of research on many chronic diseases. These include various types of cancer, as well as diseases with inflammatory, metabolic, cardiovascular, autoimmune, neurological, and psychiatric components. Recent studies suggest that differences in gut microbiota composition and changes within it play an important role in the development of obesity and obesity-related diseases. However, research is still ongoing to determine whether the changes in microbiota found in obese individuals are a cause or a result of obesity. Our microbiota:

• Generates energy from dietary fibers
• Regulates gut permeability
• Modifies inflammatory processes
• Regulates tissue fatty acid composition
• Secretes various proteins from the intestines

Thanks to these functions, it impacts body fat metabolism and carbohydrate metabolism. Of course, we must also remember that energy production, such as from muscle tissues or the liver, is also important. Thus, we cannot claim that our microbiota is our only energy source. While microbiota does affect gut permeability, it is not the only determining factor. We must also consider a healthy mucosa, active blood circulation, and antibodies and hormones secreted by cells in the digestive system.

It is important to note that in obese individuals, some bacterial species are reduced, while others increase, and bacterial diversity decreases. These changes are reversed with weight loss. Additionally, nutrition with prebiotics and probiotics has been shown to help balance the microbiota and assist in weight loss. We can say that progress will be made in understanding and treating obesity through manipulating the composition, structure, and number of microbiota.

There also seems to be something to say regarding childhood allergies and diseases like asthma. Moreover, it is believed that microbiota plays a significant role in inflammatory bowel diseases, especially in Clostridium difficile infections. However, cause-and-effect relationships have not yet been definitively established. In the West, especially in the U.S., many centers are conducting trial studies on this subject.

Genetic Inheritance

Since the gut microbiota is unique to each individual, it is, in fact, a genetic inheritance. The lifestyle and dietary habits passed down from family, as well as environmental factors, medications, and many other parameters, influence and alter this "living" microenvironment that is different for every individual. Therefore, there are no easily accessible, proven tests that can be used universally, and it seems unlikely that such tests will be available anytime soon. Despite this, stool tests can help us understand the state of our microbiota, but we are still far from knowing which diseases we are predisposed to based on this.

The genetic material of the microbiota is referred to as the "microbiome." However, these two terms are often used interchangeably. The number of genes in the microbiome is 100-150 times greater than the number of genes in the human genome. This means that, in a way, we are made up of 10% human cells and 90% bacterial cells and genes.

Which Foods are Beneficial for Our Microbiota?

It is undeniable that high-fat and high-protein diets have a negative effect on the gut microbiota. In contrast, consuming foods rich in prebiotics (nutrients that feed probiotics) and probiotics (beneficial bacteria for human health) is certainly very beneficial.

Foods high in prebiotics: Bananas, apples, asparagus, cabbage, Jerusalem artichoke, artichoke, garlic, onions, legumes, whole grains, potatoes.

Foods high in probiotics: Kefir, yogurt, sauerkraut, tarhana, sourdough bread, boza, turnip.

Flora or Microbiota?

The term "flora" originated from the old belief that microorganisms in the intestines were of plant origin. However, today, we understand that microbiota consists of bacteria, fungi, viruses, and other microorganisms. Although both terms are still used together, the correct term is microbiota.