Canadian scientists have discovered that your gut microbiome plays a key role in the development of your brain – by trawling through baby poo.
The human microbiome consists of a community of microbes living in your gut. A recent study, published in the journal PLOS ONE, reveals that the specific combination of these microbes is clearly linked to early cognitive development. In other words: what babies’ brains are able to do as they grow.
Previous studies have shown the influence of our microbiomes on adult brain health, but this is the first to focus on how it helps us build a healthy brain at the start of our lives.
So how did they do it? Scientists at the University of British Columbia, Canada, investigated the poo of 56 babies aged between four and six months old.
The babies then undertook at least one of three cognitive tests. The first, known by scientists as the ‘point and gaze’ test, assesses babies’ social attention.
This involves pointing at an object and observing the infant’s gaze upon it. The test measures an infant’s ability to share focus on an object with another person.
The scientists found that the babies with the most success in this test had higher amounts of certain groups of microbes in their gut, such as the genus Eggerthella and the Actinobacteria phylum. These babies also had lower levels of ‘bad’ microbes, like the Hungatella genus, and the Strepcococcus genus, which can cause diseases and infections like Strep A.
For the second test, the babies listened to a steady beat while the scientists measured their brain activity. Using a brain imaging technique called electroencephalography (EEG), the team assessed the brains’ rhythmic processing of the sound.
The babies who processed the rhythm better also tended to have similarly high or low levels of particular microbes to each other. Further, these ‘successful’ babies’ bodies showed similar levels of microbe-related chemical reactions to those which have been linked to brain and spinal cord development in previous studies.
For the third test, the team had the babies listen to recordings of human speech played both forwards and backwards. Meanwhile, they measured the blood flow in their brains using another brain imaging technique called functional near-infrared spectroscopy (fNIRS).
This test, however, did not show a link between the babies’ microbiome composition and their blood flow.
Overall, the findings suggest that the human gut microbiome influences cognitive development. As a small, pilot study, though, the scientists recommend further replication and research in order to confirm and build on their findings.
"There are ways to boost the infant’s microbiome, some by promoting the proliferation of healthy microbes either by ingestion of nutrients such as dietary fibers or by consuming foods with beneficial bacteria such as fermented foods like yogurt," one of the paper's authors Sebastian Hunter told BBC Science Focus. "[Also] by decreasing over-sanitization as the interaction with a wide variety of microbes is necessary for training our immune system to react accordingly.
"Future results could highlight certain microorganisms or metabolic compounds that could be supplemented or targeted to promote a healthier development of the neural systems."
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