Toddler brain development: Bacterial clues found in dirty baby diapers

July 17, 2017 by Matt Englund
toddler
Credit: Peter Griffin/public domain

If you're the parent of an infant, diaper duty probably isn't your favorite part of the day. But you dutifully check the contents of each one because your pediatrician told you that color and consistency of what they leave behind can tell you a lot about their health. But what does a dirty diaper have to do with your baby's brain?

According to first-of-their-kind findings from the UNC School of Medicine, the answer may be a lot.

Using taken from dozens of one-year-olds and cognitive assessments of the same children a year later, researchers in the lab of Rebecca Knickmeyer, PhD, associate professor of psychiatry, found an association between certain kinds of microbial communities and higher levels of later on. The results were published in Biological Psychiatry.

"The big story here is that we've got one group of kids with a particular community of bacteria that's performing better on these cognitive tests," said Knickmeyer. "This is the first time an association between microbial communities and cognitive development has been demonstrated in humans."

The gut is home to trillions of microbes that can have an enormous impact on the health of individuals, affecting everything from our ability to metabolize the nutrients in our food to our risk for developing gastrointestinal disorders like colitis. This community of microbes, also known as the , can be characterized in several ways, but one of the most common is to estimate the relative abundance of different kinds of bacteria using the combined genetic material of all microorganisms in a particular environment, in this case the gut.

Knickmeyer and her colleagues sought to determine whether there might be a relationship between the gut microbiome and brain development

To establish this relationship, they collected fecal samples from 89 typically developing one-year-olds. These samples were then analyzed and clustered into three different groups, based on similarities in their .

At age 2, the cognitive performance of these children was assessed using the Mullen Scales of Early Learning, a series of tests that examine fine and , perceptual abilities, and language development.

Infants in the cluster with relatively high levels of the bacterial genus Bacteroides had better cognitive scores compared to the other two clusters. In addition, babies with highly diverse gut microbiomes didn't perform as well as those with less diverse microbiomes.

"The latter result was quite surprising," said Knickmeyer. "We had originally predicted that children with highly diverse microbiomes would perform better—since other studies have shown that low diversity in infancy is associated with negative health outcomes, including type 1 diabetes and asthma. Our work suggests that an 'optimal' microbiome for cognitive and psychiatric outcomes may be different than an 'optimal' microbiome for other outcomes."

Identifying optimal communities and learning how to shape them is a question for future research. For the moment, Knickmeyer and her colleagues are still trying to understand the mechanism linking gut bacteria communities to brain development.

"Are the bacteria actually 'communicating' with the developing brain?" asks Knickmeyer. "That's something that we are working on now, so we're looking at some signaling pathways that might be involved. Another possibility is that the bacterial community is acting as a proxy for some other process that influences - for example, variation in certain dietary nutrients."

Though the findings are preliminary, they suggest that early intervention may hold the key to optimizing cognitive development.

"This is the first study to show that cognitive development is associated with the microbiome, and so it's the very first step," said Alexander Carlson, an MD/PhD student in Knickmeyer's lab and first author of the paper. "We're not really at the point where we can say, 'Let's give everyone a certain probiotic.' But we did have a few big takeaways from what we found. One was that when measuring the microbiome at age one, we already see the emergence of adult-like gut microbiome communities—which means that the ideal time for intervention would be before age 1."

Several avenues of further investigation have been opened by these initial results, including relating the infant to other aspects of child development - including the emergence of social skills and anxiety.

"Big picture: these results suggest you may be able to guide the development of the microbiome to optimize cognitive development or reduce the risk for disorders like autism which can include problems with cognition and language," said Knickmeyer. "How you guide that is an open question because we have to understand what the individual's microbiome is and how to shift it. And this is something the scientific community is just beginning to work on."

Explore further: Breast-feeding's role in 'seeding' infant microbiome

Related Stories

Breast-feeding's role in 'seeding' infant microbiome

May 8, 2017
Mothers protect their babies and teach them habits to stay healthy and safe as they grow. A new UCLA-led study shows that beneficial bacteria from mothers do much the same thing.

Researchers devise methods to identify transmission of microbes from mothers to infants

January 17, 2017
It has been assumed that mothers pass on gut microbes to their infants during and just after delivery, a process called vertical transmission, but because of limits in available technology, the evidence of this occurrence ...

'Genetic scalpel' can manipulate the microbiome, study shows

April 20, 2017
The gut microbiome is crucial to health, encompassing bacterial communities that possess a hundred times more genes than the human genome. Its complexity has hampered investigation of possible roles of the microbiome in a ...

People susceptible to atopic dermatitis have different microbes living on their skin than non-sufferers

July 27, 2016
Microbial communities living on the skin of people susceptible to the skin disease atopic dermatitis differ from those of healthy individuals. This finding by A*STAR researchers provides insight into the roles that resident ...

'FishTaco' sorts out who is doing what in your microbiome

January 19, 2017
A growing body of evidence indicates that the trillions of microbes that live on and inside our bodies affect our health. Collectively, these resident microbes form our microbiome.

Recommended for you

Oxytocin turns up the volume of your social environment

September 20, 2017
Before you shop for the "cuddle" hormone oxytocin to relieve stress and enhance your social life, read this: a new study from the University of California, Davis, suggests that sometimes, blocking the action of oxytocin in ...

Self-control may not diminish throughout the day

September 20, 2017
After a long day of work and carefully watching what you eat, you might expect your self-control to slip a little by kicking back and cracking open a bag of potato chips.

Researchers develop new tool to assess individual's level of wisdom

September 20, 2017
Researchers at University of San Diego School of Medicine have developed a new tool called the San Diego Wisdom Scale (SD-WISE) to assess an individual's level of wisdom, based upon a conceptualization of wisdom as a trait ...

Alcohol use affects levels of cholesterol regulator through epigenetics

September 20, 2017
In an analysis of the epigenomes of people and mice, researchers at Johns Hopkins Medicine and the National Institutes of Health report that drinking alcohol may induce changes to a cholesterol-regulating gene.

One in four girls is depressed at age 14, new study reveals

September 20, 2017
New research shows a quarter of girls (24%) and one in 10 boys (9%) are depressed at age 14.

Tablets can teach kids to solve physical puzzles

September 20, 2017
Researchers confirm that when 4-6 year old children learn how to solve a puzzle using a touchscreen tablet, they can then apply this learning to the same puzzle in the physical world. This contradicts most previous research ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.