Early In Life Exposure to Antibiotics and Altered Brain Development

Some might say it’s self-flagellation, but I can’t help myself reading the latest research into the effects of antibiotics early in life.  By now, my regular readers are all-too-familiar with my son, Alex’s, history.  For those new to The Biome Buzz, Alex is diagnosed with autism and was very physically ill much of his life.  He was put onto 5 days of  IV antibiotics at 36 hours old when he developed a fever, and immediately I noted differences in him from other babies. It turned out the antibiotics were entirely unnecessary:  he was released without any diagnosis. No bacterial infection was found.  I am not one to oversimplify things:   I am perfectly aware of the fact that this was not a one-shot insult that resulted in his autism.  But research over the last decade and half as all pointed in one direction:  early introduction of antibiotics – while potentially life-saving – has major repercussions on the gut biome and brain development.

A new paper just came out of the University of Minnesota that is worth reporting to you.  I was shocked by the paper’s opening sentence: “According to current estimates, ~10% of all newborns in the United States are treated with antibiotics immediately after birth, with many of these exposures being unnecessary.”[i]  TEN PERCENT?!  And then we wonder why there is an exponential increase in autism, ADHD and related disorders?!  We know that antibiotic exposure during childhood has been linked now to an increased risk for obesity, asthma and inflammatory bowel disease, and more.  (I have written about this topic many times.  Look here and here, for just 2 examples.)

Animals studies show that the subsequent alteration to the gut biome leads to alterations in brain function: both cognition and behavioral changes are seen.  In particular, the hippocampus seems vulnerable.  This part of the brain is critical to recognition memory and cognitive function.  These researchers actually studied the effects of very early antibiotic exposure on human infants:  one of the only studies ever to have done so.  They used a type of EEG called event related potentials (ERPs) to measure how babies exposed to antibiotics within the first month of life respond to their mothers’ voices versus strangers’ voices, in comparison to unexposed control infants. Using this technique, they could measure “recognition memory.”  The lead researcher explains that, “Recognition memory is one of the earliest types of explicit memory to develop and is known to be dependent on medial temporal lobe structures, including the hippocampus, the brain region affected by microbiome perturbation in animal models…”[ii] 72 infants in total were included in the study, 15 of which were antibiotic-exposed, 57 were controls.

Their findings:  “…infants exposed to antibiotics soon after birth who are otherwise healthy following a negative evaluation for sepsis have altered auditory processing and discrimination at 1 month of age.  Infants in this antibiotic-exposed cohort represent an at-risk group…”  While no one denies that there are cases in which antibiotics are absolutely necessary, “…efforts are ongoing to improve antibiotic stewardship…”  The goal is to reduce  use to only cases in which it is absolutely essential, and also, to develop treatments to alleviate the negative consequences of that necessary use.  The authors conclude that “…our study shows that infants exposed to antibiotics during the birth hospitalization, and subsequently ‘ruled-out’ for infection, demonstrate altered attentional perceptual discrimination responses at 1 month of age. While this group of infants was exposed to several risk factors, the observed changes in perceptual encoding provide support for the hypothesis that a healthy gut microbiota–brain axis contributes to brain development.”

Please don’t walk way after having read this thinking that this is THE cause of developmental issues.  Notice the authors specifically state that the babies were exposed to several risk factors.  As just one example, diet:  it is already known that babies fed breast milk, as opposed to formula, demonstrate “…faster speeds of processing for both auditory and visual stimuli…”  (In this study, all the babies were essentially fed the same so diet was not a factor.)  There is almost certainly not any ONE reason:  however, there is really overwhelming evidence that early exposure to antibiotics is highly detrimental.   I look forward to, in the future, reading more about how we can remediate it.

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[i] Hickey MK, Miller NC, Haapala J, Demerath EW, Pfister KM, Georgieff MK, Gale CA. Infants exposed to antibiotics after birth have altered recognition memory responses at one month of age. Pediatr Res. 2020 Sep 12:10.1038/s41390-020-01117-7. doi: 10.1038/s41390-020-01117-7. Epub ahead of print. PMID: 32919394; PMCID: PMC7952463.

[ii] https://www.news-medical.net/news/20210315/Study-shows-evidence-based-interventions-can-improve-infant-brain-health.aspx