The Venezuelan microbiologist recalled the findings of her research. The mouth has a large number of bacteria, many of which are not harmful and are even beneficial. However, others can cause infections. “It is fascinating”, she says. “You can see the gradient of urbanization very clear”: As urban people, we adopt the industrialized lifestyle and live in cities; on the other hand, they adopt “a lot of practices” that are antimicrobial.
And it is not only about hygiene habits, but about the consumption of antibiotics, the use of antibacterial substances and preservatives. “Cans do not rot just because they are full of microbial inhibitors; in this culture of processed and preserved diets, there is a lot of antimicrobial agents that we are also eating”.
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“All these modern practices seem to be causing a loss of diversity (of the microbiota) and with that functions are lost. In parallel, an increase in immune and metabolic diseases is associated with modern, urban lifestyles, and we think that these 2 things are causally linked. We are losing important functions that the microbiota has and, if that impact happens very early in life, it leads to poor development of the immune system and the metabolic system”, she explains.
She also cautions that determining causation in humans is very complicated, and doing clinical trials with people is very expensive. So the first step has been to experiment with mice.
The expert biologist points out that in remote communities, which are very small villages, there is no agriculture or animal production systems. And that has a direct effect on them.
“Jungle villages have their own pests, but unless introduced by contact with strangers, they lack our common infectious pathogens, agriculture-related bacteria (virulent Escherichia coli, Salmonella) or zoonotic viruses (influenza, HIV)”, she had written in her 2016 scientific article. And that finding was recalled during our conversation: “You realize that a lot of our gastrointestinal pathogens, most of them, come from our meat and poultry production systems”, she adds.
The experience of living with indigenous communities has also allowed her to know the cleansing habits of some of them. “They bathe many times a day in the river; their children spend much time in the river. They do not use soap, but to be clean you realize that you do not really need to use soaps”.
“I stopped showering and life went on”, says the preventive medicine expert and Yale professor who also questions how and how much we bathe. Typically, when we arrive, in the first days we use iodine: 1 drop per liter of water”.
“By day 4, we do not know where we left it. Instead of going to the river, which is far away, we end up consuming the water they have stored before. You know, all the children in the community play with that water; they even put their hands in it and, sometimes, their hands have feces, but no one has pathogens to transmit, partly because there are no E. coli from cows or Salmonella; there are no pathogens of zoonotic origin either and, inexorably, we all end up drinking that water”. “If we are going to be there for 3 weeks, we are not going to go to the river to collect water so often but nobody gets sick. That has been a great teaching”, she comments.
Their feeding habits
In some of the communities that Domínguez visited, “any mother dresses up with her baby and goes to work. First, she carries him on her chest and then behind her. These women do a tremendous exercise with a weight on them and they have correct postures. They squat down, which is a very healthy position”.
Families “do not sit down to eat 3 times a day, just like we do. They typically sit together in the evening and eat together to talk. During the day, there is a permanent feeding habit. They eat a cassava portion, then a banana, then another fruit, and they keep doing that all day long. They also have some pineapples worth to die for”, she says with a tiny smile. “If you keep eating fruit and cassava portions all day long, then you spend that day without being hungry”.
Aerial photos show that the Yanomami tribe in the Amazon remains isolated from the outside world. “Then at night, there is a fish soup with tuber or, if there was hunting, red meat. But what they eat of red meat is like a meatball, literally every week. That is the portion and, hopefully, twice a week”.
“They go out hunting and, when they return, they bite the prey and what they touch per person, because they share it with the community, is a meatball. It is a super healthy diet. It is not a vegetarian diet, although it is really exceptional to eat red meat. They eat fish soup every day. The pot is constantly boiling; they pour water on it, take out the fish, eat it, put in another fish, and that very same process is repeated over and over again. It is very interesting to see how you do not have to be using soaps or detergents”.
Findings from a social experiment
“We did an experiment and we studied ourselves, all 7 visitors. We stopped using shampoo, soap, toothpaste, but we did not give up using our toothbrushes. After that, we told them: ‘You can optimize health, we have made many mistakes. It is you who have to understand why your diet and physical activity are appropriate”, says Domínguez.
“We said to ourselves: how much are we willing to give up, especially substances, chemicals?” A couple of scientists, she comments, even stopped wearing their boots and went barefoot around that village. “Shortly after that, they ended up removing chiggers (very tiny organisms) out of their feet. By the way, I did not eat worms”, she clarifies. But a couple of her colleagues did.
“We wanted to study the following: if you incorporate yourself into their diet entirely and stop using shampoo, detergents, soaps, and toothpastes… How much does your microbiota change?”
“We did not approach the microbiota of all of the inhabitants, but there were a couple of children, 4 and 6 years old, respectively, who were the children of 2 doctors and who did increase their diversity and became closer each other. That was a very small study, a pilot study, but it opened the possibility of asking ourselves: how long does the development of the human microbiota last?”
And it is what it is believed; that during our first years of life, the composition of the intestinal microbiome is assembled and will persist during adulthood, when that microbial ecosystem reaches a state of equilibrium.
Another research study, in which Domínguez co-authored, analyzed the microbiota of a group of individuals and found that, after 3 years old, children could no longer be distinguished from adults in terms of microbiota.
To be continued……