When you think of the digestive system, it is customary to associate it with the image of a set of organs exclusively dedicated to shredding, metabolizing and digesting food.
A little as if it were a kind of engine in which to throw fuel in, which will then make the whole machine in our body work.
In fact these are the main functions of the whole apparatus, but the mechanism not is purely linear : even focusing on a single portion, such as the intestine, we will realize that the speech is not as simple as it seems.
The intestine alone corresponds to about 75% of our system digestive and divides into two macro sections, tenuous and large , each with specific functionality.
The small intestine is the longer long of the two and is also called the small intestine.
It is divided into duodenum, jejunum and ileum and is responsible for most of the chemical digestion of the macromolecules that make up food, favoring the passage of nutrients into the bloodstream.
The large intestine is shorter and broad , and this is where the reabsorption of water and some vitamins.
It is divided into cecum, colon (ascending, transverse, descending), sigma and rectum: it has the task of terminating the remaining processes of the digestive system, forming and compacting the part of the food that is not digested for subsequent elimination.
The performance of the various functions by the intestine is possible thanks to the particular conformation of its mucous membranes, which differ greatly depending on the individual section examined.
So far nothing out of the ordinary, although unquestionably complex we are essentially talking about a long tube.
But the intestine is not just this .
An important player in the entire digestive system is the microbiota , what we commonly call bacterial flora: it includes a set of heterogeneous microorganisms including bacteria, fungi and viruses living in close symbiosis in the human intestine without damaging it.
As guests we provide the undigested material necessary for the sustenance of the microbiota, while in return we benefit from the latter for the various functions it performs.
When this coexistence is in equilibrium there is a condition of eubiosis and health , while in the case of alterations and dysbiosis the development of diseases and disorders is facilitated.
The intestinal microbiota plays numerous functions in our body and some of the most important roles concern the maintenance of the integrity of the intestinal mucosa , the supply of nutrients such as some vitamins and the protection against pathogens.
Specifically the microbiota :
- contains bacteria that ferment undigested food material, producing short-chain fatty acids ( acetic, propionic and butyric acid ), molecules that are very important for our well-being, as they are the source energy of enteric cells (essential for digestive functions);
- enhances the barrier effect of the intestinal mucosa and prevents the adhesion of pathogens to the intestinal epithelium, providing a physical obstacle;
- modulates the components of the intestinal immune system with a pro-inflammatory action;
- promotes digestive processes and absorption, keeping the intestinal mucosa healthy and effective;
- is essential for the production of certain essential vitamins, such as vitamin B12, vitamin K and folate (vitamin B9), a vitamin involved in DNA synthesis and repair.
A quantitative or qualitative alteration of the microbiota can lead to dysbiosis, a state that neutralizes the positive functions of the microbiota, thus favoring the absorption of toxic substances, the development of autoimmune diseases, the possible malabsorption of nutrients and weight loss, gastrointestinal symptoms, overproliferation of pathogens and vitamin deficiencies .
Because it is said to be a second brain
How many times have particular situations such as stress, fear or happiness affected our current diet?
It is something that does not happen by chance: our belly is the part of our body linked most strongly to ours head , in fact we often speak of ” second brain ” referring to the intestine.
As strange as it may seem, in fact there is a real enteric nervous system, that is a brain of the intestine that governs digestive activity independently and that uses the same type of mediators of the central nervous system to respond to stimuli .
The resulting gut-brain axis refers to a network of information between the gut microbiota and the brain that communicates in both directions with the same language: the number of neurons that make up the enteric nervous system (millions! ) is comparable to the number of neurons in the spinal cord.
The reason why this network exists is soon said.
From a physiological point of view, the intestine is the part of our body that guarantees our survival , the only way for us to assimilate nutrients: evolution has therefore equipped us with a system, the nervous endocrine system, to carry on these fundamental functions in complete absence of input from the brain or spinal cord .
Just like the central nervous system , the enteric system deals with endocrine signaling (the signals of hunger and satiety) and the activation of the immune system, and it does so through the vagus nerve, using neurotransmitters such as serotonin.
In recent years this aspect has been studied in greater depth than in the past and the belief that there is a connection between intestinal microbiota and various psychiatric conditions, such as schizophrenia and depression, is growing stronger , due to the alteration of brain functions that can be triggered by this communication, if altered.
The connection is strong enough to direct a substantial number of clinical studies also in the search for a connection between neurodegenerative diseases and intestinal health.
Taking care of the intestine: potentiating nutrition and eubiosis
Maintaining the condition of eubiosis, which is a good state of balance and intestinal health, is essential to preserve our health in general.
A key role in modulating the composition of the intestinal microbiota is certainly given by eating habits.
Studies that examined the gut microbiota of fed subjects following a Western diet , with a prevalence of processed and refined foods, and that of subjects who had a diet rich in fiber, found fundamental differences and specific changes in the composition based on the different dietary intake.
We have seen how an unbalanced diet can promote the growth of specific bacterial strains , with consequent alteration and direct effect on intestinal pH, on the development of a pathogenic flora or an increased proliferation of bacteria in kind “good”, whose presence in excess can cause disturbances.
A high-fat diet also favors the development of a pro-inflammatory intestinal microbiota and the consequent increase in intestinal permeability.
What must be done to keep the intestine healthy?
Particular attention must be paid to the intake of prebiotics and probiotics from the diet .
Often the two terms are used interchangeably, but the differences are substantial: the WHO defines probiotics as “living microorganisms which, when ingested in sufficient quantities, produce beneficial effects on the health of those who take them”, while prebiotics they are non-digestible food substances capable of stimulating the growth and functions of the microorganisms that colonize our intestine, in a selective manner for the various strains.
So basically probiotics are live microorganisms, while prebiotics are what bacteria eat.
In food we find probiotics in fermented foods such as yogurt, kefir, sauerkraut, miso, tempeh, kombucha, fermented cheeses and mother yeast. However, microorganisms often do not survive the acidic environment of the stomach: this is why special supplements of lactic ferments are often recommended in the case of antibiotic therapies.
Prebiotics on the other hand are some types of fibers, among which the most studied are inulin and fructo-oligosaccharides (FOS) and the foods that contain more are chicory, artichoke, onion, leek, garlic, asparagus, wheat, bananas , oats and soy.
Here are some guidelines to follow to ensure that the gut-brain axis derives the greatest possible benefit from our lifestyle:
- practicing physical activity to improve muscle tone and mood, helping us to reduce stress and its effects on the intestine;
- rest adequately to keep tension and anxiety under control;
- limit the consumption of foods that are too fatty, of preparations that are too elaborate or rich in condiments ;
- limit aggressive cooking methods such as fried food , preferring low temperature or steam cooking;
- avoid frequent consumption of alcohol and soft drinks rich in sugar but low in nutrients;
- consume an adequate amount of water: at least 1.5-2 liters per day;
- include foods rich in soluble and insoluble fiber in your diet, such as whole grains, legumes, vegetables and fruit.
You can be decisive in managing your health starting with a simple gesture like that of eating: an efficient and performing gut-brain system can depend on an empowering diet, for make you live every day to your fullest potential.