Your body is not the only thing that grows rapidly during the first years of life. Your microbiome, the population of bacteria that live in your gut and elsewhere in your body has a growth spurt, and too confusing, it could lead to health problems down the line. A new study in mice shows that the interruption of the development of intestinal microbial populations with low doses of antibiotics early in life disrupts their metabolism and increases the risk of obesity later.
In recent years, researchers have realized that the microbes living in your gut are crucial to several functions, including building a strong immune system. Early childhood is a particularly important time for the development of a robust microbiome, a process that begins with the germs of a newborn picks up on its way through the birth canal. Children born by Caesarean section and those who receive antibiotics during their first year of life, have a higher risk of developing immune disorders such as asthma and type 1 diabetes Epidemiological studies show a high risk for obesity in children and, although the effect seems to be very low.
But Martin Blaser, a microbiologist at the University of New York in New York City, suspected that the development of microbiome has a greater impact on metabolism later in life. Studies with animals such as pigs and chickens have shown that low doses of antibiotics when animals are young people caused their faster growth and increased the amount of fat they won. Blaser and his colleagues wanted to determine whether metabolic changes are driven by the way antibiotics changed the microbiome of the animal, and they have turned to mice to study the link.
Blaser and his team were given a low dose of penicillin to mice for the first 4 or 8 weeks after birth and analyzed their gut microbiota and several metabolic characteristics. As expected, penicillin changed the gut microbiota in animals by reducing the number of lactobacilli and several other species that are believed to be beneficial. But this effect disappeared after a few weeks of last dose of antibiotics. Ten weeks later, however, the treated mice who ate diets rich in fat began to gain weight like crazy, reports the team today Cell . Women were particularly vulnerable: They added twice more body fat as their untreated cousins who ate the same diet high in fat. Mice dosed with antibiotics that fed the normal diet did not gain weight, nor older mice who received antibiotics.
To determine whether the mouse'S microbiomes disturbed or the antibiotic itself caused metabolic changes, the team transplanted mice treated microbes in previously kept completely germ-free mice. Beneficiaries immediately began to gain weight when put on a diet rich in fat, suggesting that the cast changed microbiomes was responsible for metabolic changes. Meanwhile, the mouse germ-free given the gut microbes untreated mice did not gain weight.
"This is a very good study because it goes beyond the correlations and prove causality," said microbiologist Willem de Vos from Wageningen University in the Netherlands, who was not involved in the study. Jeremy Nicholson, a biomolecular scientist at Imperial College London, says that the study shows that changes in the overall physiology of organisms may indeed result from relatively small perturbations of the intestinal microbiome ", which could affect the long-term health. "
Vos warned against jumping to conclusions about what it means to study the man whose entrails contain very different bacteria than do those of mice. Moreover, he adds, "you would never give a low dose of antibiotics to a child for a long time. you want to know the impact, repetitive short treatment with a high dose." in addition, future studies need measure the impact of different antibiotics than penicillin, he said.
Blaser agreed that more work must be done, but he is confident that the connection between early life antibiotic use and obesity will eventually be confirmed in humans. "A lot of work on obesity has focused on food and calories. This was not sufficient to explain the obesity epidemic," says Blaser. Antibiotics could be a missing piece of the puzzle.
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