Why gut health is key to your overall well-being
Last updated: 15th November, 2024
April 28th, 2023
Research and professionals often mention that gut health is essential to overall well-being. However, what exactly is meant with the term gut health? How is the gut linked to well-being, and why is this important? In this article, we will explore the importance of gut health, and its role in maintaining a good overall health.
The gut is a multi-functional organ
The gut is not only important for the digestion and uptake of nutrients from food. The gut also forms a physical barrier that protect us from many different pathogens. Hereby, the gut serves an immunomodulatory role, protecting against inflammation. Intestinal health can also affect mood and cognition through communication between the gut and the brain, called the gut-brain axis. The microorganisms that reside in the gut play a major role in how gut health influences overall well-being (1).
The gut is also called the gastrointestinal tract or the digestive tract. It consists of the entire pathway from when food first enters the body and the remnants that leave the body again. Along the way, the food gets digested, and nutrients are absorbed to be used as energy sources and building blocks, in order to support the overall physiological functioning of the body (1).
What is the structure of the gut?
The gut is approximately 9 meters long, with the small intestine taking up 6 meters of this length. The lining of the gut consists of 4 distinct layers. The villi and microvilli that texture the gut epithelium, increase the surface area at which the absorption of nutrients can take place. Underneath the outermost layer, blood vessels and lymph vessels are in close proximity to the surface of the gut. This allows for the fast absorption of nutrients into the bloodstream (2).
The gut contains many cells that are important for immune function. They facilitate the secretion of enzymes and mucus into the lumen, or hormones and other messaging molecules into the blood. The lymphatic system is part of this, as it is home to many immune cells that can fight pathogenic intruders. A protective mucus layer covers the epithelium, which makes it more difficult for pathogens to pass through (3).
Gut microbiome
Another important component of the gut are the commensal microorganisms that reside there; the gut microbiota. These microorganisms consist of many different species of bacteria, archaea, viruses, and fungi, and the composition is unique for every person. Bacteria make up the vast majority of the gut microbiome, with around 1000 different bacterial species that reside in your gut!
The microbes in the gut elicit many important functions. They support energy metabolism, by fermenting otherwise undigestible dietary fibres into short-chain fatty acids (SCFAs). SCFAs can be used as an energy source for intestinal cells, and serve as anti-inflammatory signalling molecules. Due to their presence in large quantity, the gut microbiota can oppose colonization by pathogens, stimulate tolerance towards antigens, and induce the production of the protective mucus layer (4).
What is gut health?
Gut health refers to the overall functioning of the gut, in the absence of digestive symptoms. The gut microbiome plays a central role in this; there has to be a balance between the helpful and potentially harmful microorganisms in the gut, as this can affect the integrity of the gut. Therefore, crosstalk between these microorganisms and the gut epithelium plays a pivotal role in one’s health status (5).
There are multiple factors that can affect the composition of the gut microbiota, influencing the function and integrity of the gut barrier. These include environmental factors, including where you live, your age, what you eat, how physically active you are, but also stress levels, and the use of antibiotics, as well as genetic factors (6).
Why is gut health important?
Immunology
The gut forms a protective barrier against gut microbes, pathogens, food antigens, and toxins to which the body is exposed at the level of the gut. In fact, the intestine forms the largest internal barrier, and is therefore essential for the protections against harmful substances. Next to the physical barrier, as many as 70-80% of the immune cells reside in the gut.
The immune cells in the gut secrete antibodies and antimicrobial proteins. Together with the epithelial and mucus barrier, they protect the underlying tissues form the translocation of pathogens that might be present in the lumen of the gut. The cells of the gut are held together by so-called tight junctions, which can loosen to become more ‘’leaky’’. This can be beneficial by aiding in the absorption of nutrients, or disposing of the inflammatory stimuli that did manage to cross the gut barrier (diarrhoea).
However, an excessively leaky gut allows for ‘’bad’’ bacteria and other pathogens to enter the blood stream and cause (chronic) inflammation. This can further increase gut barrier dysfunction and disease. Dysbiosis – an imbalance between the favourable and unfavourable microbes in the gut – is a major cause of a leaky gut. (7, 8)
Gut-brain axis
Gut health is also important for brain health and cognitive function. There is bidirectional communication between the central nervous system – the brain, and the nervous system that resides in the gut. Interestingly, the majority – up to 90% – of the body’s serotonin is produced in the gut. Serotonin is the so-called ‘’feel-good’’ chemical, which plays an important role in the modulation of mood, learning, and memory.
The gut microbiota play an important role in the communication between the gut and the brain. The SCFAs produced by the gut microbiota are able to cross the blood-brain barrier, and directly communicate with the brain. Likewise, dysbiosis of the gut microbiome can alter the blood-brain barrier, possibly contributing to inflammation of the central nervous system, which is linked to depression and anxiety-like disorders (9).
How to support Gut Health?
There are plenty of ways to support gut health. First of all, probiotics can be used to maintain a healthy community of microorganisms, by supplementing directly with live microorganisms. Next to that, prebiotics derived from non-digestible carbohydrates can be used to selectively stimulate the growth of intestinal bacteria. Another way to enhance gut health is through the use of the bacterial products or metabolites released from microbial fermentation; the so-called postbiotics.
Gut health is the foundation of good health
All in all, it is quite evident that keeping the gut healthy is of great importance for one’s overall well-being. The gastrointestinal tract, which is the home to many different microorganisms, takes care of digestion and absorption of foods and nutrients needed to perform all basic functions. Next to that, it plays crucial role in the defence against pathogens, and through its bidirectional communication with the brain, has a significant impact on mood and cognitive function.