We are about to embark on a fascinating journey that takes place within us. The starting point is found in microorganisms that mainly inhabit the gastrointestinal tract. This group of microorganisms is headed by bacteria, but it also has viruses and fungi among its ranks. We are talking about the intestinal microbiota, an amazing system capable of influencing the brain from the distant intestine, even determining our emotional state and influencing certain mental pathologies. Amazing right? Come with us, we’re leaving now!
“The microbiota is made up of the set of microorganisms that we have, basically in the gastrointestinal tract, which are not only bacteria but also viruses and fungi, which make up a whole microsystem that continuously sends messages to the rest of the body,” the doctor tells us. Amanda Rodríguez-Urrutia, psychiatrist and author of the book Feel what you eat , from the Diana publishing house. There are also other microbiota that are located in different parts of the body such as the skin, the vagina or the stomach. However, the intestinal is the most numerous and important, as it houses 95% of the microorganisms.
It is precisely the intestinal microbiota that connects with other parts of the body through substances produced by the microorganisms found there. “The bacteria that we have in the intestinal tube release some substances and those substances are the ones that impact the intestinal barrier and from there they pass the barrier and go into the bloodstream. Messages are sent from there, through the immune system, they also touch the hormonal system and go to the rest of the body, including the central nervous system, that is, the brain”, explains Rodríguez-Urrutia.
We are now at one of the most surprising points related to the microbiota and its ability to influence the brain . From a scientific point of view, the microbiota has not been well studied, but as the doctor tells us, it is known that the microbiota is essential for the correct development of the brain. “We know from animal models that if the microbiota is not properly colonized early in life, that brain does not develop properly. The microbiota and brain development go hand in hand and a good bacterial colonization of that living being makes that brain develop properly”, explains the expert. Throughout life, the communication between the microbiota and the brain will continue to be active and a good microbiota will have a positive impact on brain function. Also the other way around.
Amanda Rodríguez-Urrutia, who is also participating in a European research macroproject called DISCOvERIE , which studies the brain-intestinal mechanisms common to pathologies such as depression or irritable bowel syndrome, tells us that it has already been seen in studies with humans that What we eat impacts our brain in real time, stimulating certain areas, such as those responsible for processing emotions . “You eat something, it goes to the microbiota, the microbiota sends messages to the brain and modifies it. It makes perfect sense to think that if you have an altered microbiota, you can send altered messages to the brain. By modifying the microbiota we can modify mental states, we can even modify depressive disorders ”, says the expert. Here is the magic.
Today there is much talk of dysbiosis , or what is the same, the alteration of the microbes that exist in the microbiota. One of the most surprising findings in this regard is the connection that could exist between this phenomenon and Alzheimer’s or autism. “The microbiome functions as an organ that also has functions in the body. It is normal to understand that it impacts the entire body. Autism has been linked to intestinal dysbiosis. The altered microbiota generates disorders in the intestinal barrier and an incipient marker of Parkinson’s has been seen”, explains the expert, who adds that many medical disciplines are currently paying special attention to the human microbiome. In the case of psychiatry, connections have been observed between an altered microbiota and attention deficit hyperactivity disorder , since in this pathology the microbiota is also altered, as we have mentioned, in autism. What is not yet known is what happens first, if the pathology or the alteration of the microbiota. “We don’t know if the disease itself generates this microbiota or if it’s the other way around,” says the researcher. Rodríguez-Urrutia gives as an example people who suffer from depression, who generally tend to eat poorly. Do they eat poorly because their microbiota is altered and as a consequence they became depressed? Or do they eat like this as a result of the depressive state and consequently alter their microbiota? “The directionality is not entirely clear. What we do know is that there are depressive diseases that start in the digestive system and go to the brain and vice versa, there are brains that generate digestive disease and intestinal dysbiosis ”.
Foods that impact the brain
At this point in our journey, which began in the gut and will end in the brain, we can sense that what we eat may have an impact on the central nervous system and our mood. We asked the expert what we can eat to maintain a good brain condition. “Studies have shown that the Mediterranean diet has an anti- inflammatory property and an intestinal barrier function, which are the two fundamental mechanisms by which we can begin to have systemic alterations,” he tells us. A bad diet will alter the microbiota and as a consequence the intestinal barrier will not work well and the body will become inflamed. If the organism becomes inflamed, the brain will also become inflamed. The expert recommends consuming plenty of vegetables, fruits and legumes and opting for little processed foods. It also suggests limiting the consumption of meat and that the fish that is eaten is preferably high in Omega 3 fatty acids. “It is no longer just an issue of weight or cardiovascular disease, in which the relationship is also very powerful, but also with our brain state”, emphasizes the psychiatrist.
Probiotics, prebiotics… The more, the better?
Parallel to the investigation of the intestinal microbiota, substances called probiotics and prebiotics have appeared on the scene, the use of which can be confusing for the average citizen, since the messages that reach us seem to indicate that the more, the better.
Let’s start by differentiating between one and the other. Prebiotics are non-living substances that we ingest with our food, basically fiber of vegetable origin, which serve as food for the living microorganisms that are in the intestinal tract. Prebiotics, on the other hand, are living substances that, taken in adequate amounts, provide a benefit to that microbiota. They are the lactobacillus , bifidobacteria , etc.
“We still don’t know exactly what a healthy microbiota is – Rodríguez-Urrutia tells us – but each one has a balance that is generated in the first years of life. The microbiota is formed in the first three or five years of life. From there it’s pretty stable. Age changes it but basically it is the same”. The doctor explains that if you have a healthy microbiota there is no reason to ingest anything other than what we usually take . “If you are healthy, depending on what dietary or probiotic interventions are not going to generate any well-being for you. In fact, on the contrary, if you deregulate it, you can have symptoms. If someone healthy takes probiotics, they may have flatulence, gas or cramps, ”he tells us. Therefore, not everything goes and taking probiotics while being well is not synonymous with being able to be better. Special care must be taken if you are immunocompromised or undergoing chemotherapy treatment.
At a higher level are psychobiotics , living substances that, when ingested in sufficient and adequate quantities, provide a benefit for mental health . As Rodríguez-Urrutia tells us, it is a very incipient field, but they could help treat mild and moderate depression and reduce the use of drugs such as anxiolytics that are currently used too much and poorly.
In addition to embracing the Mediterranean diet and consuming probiotics when recommended by a healthcare professional, there are other ways we can take care of our gut microbiota. The expert suggests the following: “ Sleep the hours that are due, have a balanced life in terms of stress (stress impacts the microbiota and generates dysbiosis), take a minimum of hours of sunlight per day, at least 10 minutes, and have more authentic human relationships . Emotional well-being, optimism… there are many mental states that favor the microbiota”.
