The study of the microbes in our digestive tract has become one of the most fashionable disciplines and discoveries about their role in our physical and mental health are very abundant. Even our propensity to be unhappy or happy would have some connection with these microbial partners who live in our guts.
Posted May 28
All those who have already consulted for a bad life have heard of serotonin. This neuromodulator that many depression pills try to rebalance in our brains has a strong connection to our soul waves and our resistance to stress. Today, we know that 80 to 90% of serotonin comes from intestinal cells and microbes that inhabit our intestines. It has even been found in the intestines bacteria that produce serotonin and others capable of making tryptophan, which is the main ingredient used for the synthesis of this molecule of happiness.
Author of The gut to help the brainDr. David Perlmutter says that today, 90% of our diseases have some link with what happens in our microbiota.
Like what Hippocrates was right to already profess at Ve century before our era that the intestine was the birthplace of all diseases.
The Russian zoologist Elie Metchnikoff will be the first to suspect, in the middle of the XIXe century, a link between human longevity and the bacteria that live in our digestive tract. The latter, who worked on the defense mechanism implemented by the immune system against bacteria, will also be the precursor of what will become today the gigantic field of study on the intestinal microbiota. As part of Hippocrates’ vision, Metchnikoff said that death begins in the colon. A somewhat pessimistic statement, because the intestinal microbiota is much more bearer of life than of death.
To reproduce, you have to meet a partner, seduce him, make love, hope for fertilization of an egg by a sperm, implantation, pregnancy and childbirth and the survival of the baby. At all stages of this great adventure for the perpetuation of genes, microbes are never far away. The discoveries on the microbiota are so numerous and impressive that, long after Darwin, I am among those who begin to think ironically that humans are perhaps animals held on a leash by a bacterial colony.
Let’s say our evolutionary collaboration with the bacteria that inhabit our bodies is 99% for the best. But in rare cases, mutualism can give way to a toxic relationship and you have to defend yourself.
One of the ostensible proofs of the link between the microbiota and health was made in 1980 by Australian researchers, Barry Marshall and Robin Warren, who were working on a bacterium called Helicobacter pylori. A discovery that was to lead to a real revolution in the way of treating stomach ulcers. This bacterium, which has been lounging in the human stomach for at least 50,000 years, is present in one in two people on the planet. It is therefore what can be called a long-time roommate of Sapiens, which our hunter-gatherer ancestors already housed in their digestive tract. Even if it is at peace with the vast majority of people who shelter it, in certain cases and certain conditions, it can turn into a pathogenic microbe and destabilize our digestive tract.
The two researchers then discovered that the vast majority of stomach ulcers are caused by this bacterium which is not afraid of acidity and whose secretions weaken the protective layer of the mucous membrane. This fragile exposed surface then leaves the field open to the acidity of the stomach and welcome burns, sometimes even bleeding. Before the two scientists point an accusing finger Helicobacter pylori, ulcers were suspected to be caused by stress, alcohol or coffee abuse, spicy food, hot pepper, etc. Treatments for the disease were then very invasive. In question, it was sometimes necessary to send probes into the digestive tract to assess the extent of the damage.
The discovery of Barry Marshall and Robin Warren has since made it possible to treat ulcers with a simple combination of antibiotics. To prove to skeptics who did not believe in his discovery, Barry Marshall had pushed the provocation to the point of swallowing a culture ofHelicobacter pylori. The eccentric researcher obviously had a stomach ulcer and cured it with a simple dose of antibiotics. This major discovery on the less noble role of certain bacteria in the microbiota earned the two scientists the Nobel Prize in Physiology or Medicine in 2005 and made it possible to greatly simplify the treatment of this condition.
Link between bacteria and prostate cancer?
Perhaps in line with Barry Marshall and Robin Warren, a team of British researchers from the University of East Anglia, under the direction of Colin Cooper, has recently made a lot of noise. Using cutting-edge genetic methods, these scientists have discovered bacteria that may be linked to aggressive prostate cancer. In a sample of 600 people including men with this cancer and a control group, these researchers discovered five suspicious bacterial species, three of which were previously unknown to scientists. They then found that men who harbored one or more of these species of bacteria in their urine, prostate or tumor tissue were 2.6 times more likely to see their cancer progress to a more advanced form.
A correlation that suggests that there is a link between prostate cancer and the presence of these microbes. The stakes are high, but there is still a long way to go.
If there is any real involvement of these microbes in triggering or worsening the disease, says the lead author, there would still be another hurdle to cross before adapting this new finding to therapies. Not only is getting antibiotics into the prostate not easy, but molecules that specifically target unwanted bacteria will also have to be chosen.
Although it is very early, say the authors, to say that the presence of these bacteria causes or worsens prostate cancer, the finding published in European Urology Oncology is promising enough to make international scientific and media headlines. If the causal link is confirmed, as in the case of stomach ulcers, it could eventually lead to a revolution in the way of diagnosing and treating this disease which claims many victims on the planet.
To be continued…