The first years of our lives are critical when it comes to brain development and cognition. But reading books and learning times tables can only go so far when driving this cognitive development.
Our bodies are home to trillions of microbes, collectively known as our microbiome. These microbes rapidly colonize our body from the moment we leave our mother's womb—through contact with the birth canal (if birthed vaginally), caregivers, food, breastmilk and our environment—and continue to change throughout our lives.
Increasingly, we are learning the roles of these microbes in everything from digestion to depression. However, their contribution to our early development is, for the most part, a mystery, particularly when it comes to our growing brains.
"There are a number of ways microbes can affect the brain," Kevin Bonham, a senior research scientist at Wellesley College, told Newsweek. "In particular, they can produce molecules, including neurotransmitters, that can interact with the nervous system in the gut or even get into the blood and make their way to the brain. Some microbes can also break down neuroactive molecules that might otherwise have an effect.
"In addition, the gut is filled with cells of the immune system that interact with microbes, and many signaling molecules produced by the immune system can also affect the brain."
As a result, the motherload of microbes in our guts has been implicated in a range of brain-related conditions, including mental health, autism, Parkinson's disease and Alzheimer's. But, when it comes to neurotypical brain development, we don't know what a "healthy" microbiome looks like.
In a recent study published in the journal Science Advances, Bonham and colleagues studied a cohort of 381 children from just 40 days to 10 years of age. Using genetic analysis, the researchers established the communities of bacteria present in the children's microbiome and subjected them to a range of age-appropriate cognitive testing and analysis. Finally, using MRI scanning, the team assessed the structure of their brains.
Using computer models, the team found clear associations between certain bacterial species and higher cognitive function, while other species were associated with lower cognitive scores. "I was pleasantly surprised by the number and strength of associations we saw and a bit surprised by how many of the microbes we identified were not ones I was very familiar with," Bonham said.
The computer models could also predict the structure and volume of different brain regions based on the child's microbial profile alone. However, it is still too early to determine whether a causal relationship exists between the microbial species and enhanced cognitive abilities.
"At this early stage of research, I don't think that we know enough about what a 'healthy' microbiome is, let alone how to promote it," Bonham said. "I'm not doing anything specific with my kids as a result of this research."
The research still represents an exciting first step toward understanding the relationship between our brains and bellies, especially during early childhood.
"This research is just the first step," Bonham said. "We're very keen to see if we can replicate this work in other, more diverse cohorts and begin to do experimental studies to see if we can understand specific causal links between microbes and brain development."
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Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Pandora Dewan is a Senior Science Reporter at Newsweek based in London, UK. Her focus is reporting on science, health ... Read more
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