Early Childhood Exposure to Antibiotics Increases Your Chances of Becoming Overweight in Middle Age, Especially so for WomenBy
It’s well understood that industrial farms purposefully enhance the growth of their livestock by giving antibiotics to young animals. If that’s the case with food animals, could our widespread use of antibiotics to treat infections in children be having the same effect?
The question was posed by Martin Blaser, MD, director of the Human Microbiome Program at NYU and president of the Infectious Diseases Society of America. In a series of mice experiments that he and his colleagues began in 2007 that he describes as “the most exciting work of my career,” Dr. Blaser answers the question with a decisive yes: Early life exposure to antibiotics, he says, can permanently change development leading to larger size and more fat, especially in women.
Dr. Blaser’s findings, laid out in his 2014 book Missing Microbes: How the Overuse of Antibiotics is Fueling Our Modern Plagues, can be summarized as follows:
(1) The early childhood years are a critical period in a child’s development and so the earlier they are exposed to antibiotics the more pronounced the effect of larger size and more body fat.
(2) The effect was present across all antibiotics tested.
(3) Short term exposure to antibiotics — mimicking a child’s periodic exposure to antibiotics — showed identical effects: getting antibiotics for 4 weeks or 8 weeks was the same as getting antibiotics for 28 weeks.
(4) The effect was noticed earlier in males; with females it arrived in middle age, and in both cases it persisted for their entire life span.
(5) Mixing a high-fat diet with an antibiotic exaggerated the effect dramatically: males put on 25% more body fat, but female body fat increased 100% — it doubled their body fat.
(6) Blaser reports that his findings are consistent with a human study linking obesity with antibiotic use in young children. He cites the well-known British research that tracked over 14,000 children from birth for the next 15 years. Blaser’s team reviewed the data and found that “children who received antibiotics in the first six months of life became fatter” than those who took antibiotics later on.
Thus, concludes Blazer: “So on the farm, in our mouse experiments, and in an epidemiological study of human children, there was consistent evidence that early-life exposure to antibiotics could change development leading to larger size and more fat.” (my emphasis)
We can to varying degrees combat body fat with diet and exercise, but Blaser’s use of the phrase “larger size” bears further scrutiny. In his experiment with mice that most resembled how children take antibiotics — “Instead of low doses, mice got the antibiotics just like children, full therapeutic doses for just a few days in several pulses” — he found a sobering effect that cannot be countered with diet or exercise:
[M]ice that received amoxicillin showed increased bone area and mineral content for the duration of the experiment. Perhaps the effect was permanent because they received the drugs so early in life. And since amoxicillin is the most frequently prescribed drug in childhood, I can only wonder if that’s the drug that most promotes the recent increases in human height.