Microbiota imbalance at age one predicts allergies at age five
Canadian researchers 1 are using the stools of one-year-olds to identify microbial communities that can predict subsequent allergies. Their aim is to one day change the course of things via the gut microbiota.
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On their fifth birthday, some of the thousands of Canadian children participating in the vast (sidenote: https://childstudy.ca/ ) study, which has followed these children since birth, were diagnosed with allergies such as:
- atopic dermatitis
- asthma
- allergic rhinitis
- and/or food allergies.
Since their medical records and stool samples collected at three months and one year were carefully preserved as part of the study, the researchers were able to investigate whether there were any warning signs. As it turns out, there appears to be one warning sign universal to all four allergies: the gut microbiota.
Delayed diversity and dysbiosis
Asthma, eczema, food allergies, and hay fever – whatever the allergy –, all future allergy sufferers had a gut microbiota that was insufficiently diversified at age one, as if they were much younger than their birth certs suggested. In addition to this lack of maturity, the microbiota of the future allergy sufferers presented a dysbiosis: four beneficial bacterial species were depleted, while five species generally considered pathogenic were present in excess.
Suspected mechanisms
This early imbalance may explain the lower production of beneficial (sidenote: Short chain fatty acids (SCFA) Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25. ) and the overproduction of inflammatory molecules. In turn, this leads to the subsequent development of allergies... but also gives hope of one day reversing these allergies by correcting gut dysbiosis.
"Developing therapies that change these interactions during infancy may therefore prevent the development of all sorts of allergic diseases in childhood, which often last a lifetime." 2
Not everyone is equal when it comes to allergies
In the meantime, bear in mind another result of the study: when it comes to allergies, our children are not all equal. Boys are more affected, as are children whose fathers and/or mothers suffer from allergies, and those who were prescribed antibiotics before age one. Conversely, breastfeeding up to six months protects against allergies, as does Caucasian ethnicity. While screening the origin or health record of any future spouse may be out of the question, breastfeeding should be encouraged and antibiotics used with the utmost care and only on prescription.
Antibiotics: what impact on the microbiota and on our health?
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