Your gut and brain are talking

In 2013 a study by researchers at the University of California (UCLA for its acronym in English) wrote it down and subsequent investigations continue to find evidence of this: the microbes from your gut and your brain are related, to the point of playing important roles in disorders such as anorexia, anxiety or depression.

It knew beforehand that the brain sends signals to the gut. Therefore, in part, stress and other conditions may cause gastrointestinal problems. But the interesting finding was the evidence that the brain-gut communication is bidirectional, ie the intestine also "communicate" certain things to human control center.

"Our findings indicate that some of the content of, for example, a yogurt, can really change the way our brains respond to the environment", published on the website of Ucla Dr. Kirsten Tillisch, a professor of medicine at the division of digestive diseases university and coauthor of the study.

Specifically, this research analyzed the response of 36 women between 18 and 55 years a series of tests designed to measure the commitment of brain regions related to cognition and emotions in response to visual stimuli. this type of test is chosen, reports the research because preliminary analysis in animals had linked alterations in the intestinal flora changes in behavior affective nature.

The study found that the group consuming a specific blend of yogurt with probiotics (bacteria that are believed to have beneficial effects in the intestine) twice daily for four weeks had greater connectivity between this type of brain regions.

This does not mean that those who consumed these drinks were "smarter" than others. What caught the attention of researchers was found that changes in the intestinal microbiota (this bacterial ecosystem) could be reflected in many areas of the brain, including those involving sensory processing and not just associated with emotion, Tillisch explained in the news related to their findings.

Multiple Disorders

"You probably know that there are signals from the gut to the brain and can be modified by changes in diet leads to an increase in the number of investigations aimed at finding new strategies to prevent or treat digestive, mental or neurological disorders" also he said in 2013 Dr. Emeran Mayer, professor of medicine, physiology and psychiatry and another author of the study from UCLA.

Indeed, other scientists have been interested in the subject. Sarkis Mazmanian, a microbiologist at California Institute of Technology (Caltech) has studied the bacteria Bacteroides fragilis, which is normally found in the colon of a healthy person, but can cause infection if it comes, for example, into the bloodstream.

Mazmanian and colleagues from other universities and research centers in the United States studied the effect of this bacterium in a group of mice with similar symptoms of autism in humans.

Treatment with B. fragilis, which is not normally found in the animal and sought to alter their intestinal flora, improved their behavior to make them less anxious, help them communicate better and to have a less repetitive behavior.

The exact way in which this bacteria "improved" the intestinal microbiota of animals is still not understood, says a publication in the magazine The Atlantic, but it seems to be related to the molecule 4-etilfenilsulfato (4Eps in English). The level of the chemical in the blood of mice with autism, it is believed that is produced by the microbial population of the intestine, it was 40 times higher than those without symptoms.

Also, adds the note, although the relationship between the 4Eps and the brain is not clear when the animals were injected with the compound presented symptoms similar to autism.

The suggested correlation between abnormalities in the intestinal flora and autism has been studied in humans from different perspectives. For example, scientists at Arizona State University published in 2013 the results of a study that compared a group of 20 children with autism with 20 without the disorder, and found, among others, the second population had greater diversity and bacterial wealth. They also analyzed the correlation between diversity / wealth of bacteria and severity of gastrointestinal problems in children with autism, concluding that autism and these gastrointestinal symptoms that often accompany were also characterized by lower wealth in intestinal flora.

These findings do not want to automatically say that autism produce gastrointestinal problems, rather than appear to be correlated, but motivate researchers to continue pulling the thread of the tangled relationship between the brain and these bacteria of the intestinal flora.

The contribution of neurosciences

In addition to its relationship with anxiety disorders such as autism or depression, recent studies on the subject have analyzed the links of these bacteria with the development of the brain and human behavior.

An article in the journal Nature published last year speaks of the neuroscientist Rebecca Knickmeyer, school of medicine at the University of North Carolina, and recounts his "study of feces", where through the stool investigates the bacterial flora of a group of children recently met a year old and he works since birth.

Like other neuroscientists, Knickmeyer seeks to determine whether microbes that colonize the intestine in childhood can alter brain development, an issue that has been researched and tested in animals.

Nonscientific research is part of six studies that the National Institute of Mental Health America has financed with up to a million dollars to examine the "microbiota-gut-brain axis".

Added to this, organizations like the European Union have also been interested in the subject, having nine million euros in a draft five-year investigation called "My new gut" (My new intestine).

The general objectives of "My new gut" are identified aspects of intestinal flora that are related to obesity, understand what is the influence of these bacteria and their relationship to the brain, and find ways to reduce potential disease through changes in food specifically targeted at altering the bacterial microbiota.

Increasingly questions

As with the findings of other studies, the problem with these links between gastrointestinal disorders and neurological or psychiatric disorders so far has been that "it is very difficult to determine their causes or consequences of these conditions," according to Nature Rob Knight , a microbiologist at the University of California, San Diego.

With this in mind, this accumulation of recent studies on the two-way connection between the brain and gut flora has generated a number of questions among scientists, who have found in the subject a new area to which to direct their research.

The journalist and biologist Javier Yanes recounts in his blog on science that this brain-gut relationship was the subject in 2015 of a symposium during the annual congress of the Society for Neurosciences US.

"In Congress, several researchers presented evidence that the microbiota can influence certain neurological conditions, possibly through neuroendocrine mechanisms available. In my humble eyes, this is almost the closest thing to a new paradigm that have lived for years in biology, "added the journalist.

With its possible interference with such a broad range of issues, ranging from obesity and certain diseases to mental disorders and behavioral changes, research on the subject are projected as avant-garde and interest against its findings is considerable. Especially when the topic is related to contemporary issues of medicine as abuse and self-medication of antibiotics. The latter has not only generated the birth of resistant to treatment, but also puts under scrutiny the importance of self delicate one-of balance of intestinal flora "superbugs".

However, researchers have been cautious when publishing their analyzes too lightly. A finding bad press could make sectors such as food enact the thoughtless use of probiotics, foods with added microorganisms that alter the bacterial flora. According to the World Health Organization, these are beneficial as long when used in proper amounts.

The Food and Agriculture Organization, which also recognizes the beneficial effects of these added to foods, warns that the increasing popularity and lack of international consensus on criteria to assess their effectiveness and safety forces the scientific community to continue studying the issue.

Science has indicated the existence of a two-way communication between the brain and the gut, related to the bacterial flora. The research question now is, what guts to tell the head ?.