Dirty kids make healthy kids

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By David Morrison

“After all, perhaps dirt isn't really so unhealthy as one is brought up to believe.” – Agatha Christie, Murder in Mesopotamia

It seems as if every week there’s an article in the news about a study claiming that something routinely considered healthy or harmless is now the opposite. As a consequence we have a society walking on eggshells in a drastically over-sanitized world and children who are inadvertently ultra-protected, including from factors vitally beneficial to long term health.

To reverse this trend, Peter Wall Institute Distinguished Professor Dr. B. Brett Finlay and Dr. Marie-Claire Arrieta wrote Let Them Eat Dirt, an extraordinary new book that argues compellingly against keeping children too clean. Their research indicates that exposure to microbes during early childhood may decrease the likelihood of kids developing allergies, asthma, autism, diabetes and even obesity. Finlay and Arrieta hope that Let Them Eat Dirt may ultimately bring about a radical shift in the way children are raised, thereby paving the way for a healthier population in the coming years.

“It used to be that most kids died of infectious diseases, now very few do,” says Brett. “We did that by cleaning up the world, bringing on antibiotics and vaccines and rigidly applying the adage ‘cleanliness is next to Godliness.’”

While that’s been extremely efficient in getting rid of infectious diseases, in the meantime there has been a catastrophic rise in what are called ‘Western society diseases.’

“The incidence of these diseases has not changed in places like Africa, where the adoption of clean lifestyles is not as common as in the West,” Brett explains. “So, back in the 1980s, it was supposed we were living too cleanly, that we’re not getting the necessary bugs we have spent our entire evolution developing. We were evolved to having a bug that wasn’t there anymore, so maybe something was happening, and the concept that we were living too cleanly grew stronger and stronger.”

Dr. Brett Finlay and Dr. Marie-Claire Arietta, co-authors of "Let Them Eat Dirt."

Dr. Brett Finlay and Dr. Marie-Claire Arrieta, co-authors of "Let Them Eat Dirt."

Despite the scientific complexity of the subject matter, Let Them Eat Dirt is written in such a way that everyone can understand it.  

“We wrote the book for pregnant moms,” says Brett. “Even if you’re not a scientist and you read this book, it will make sense. Much of it is really common sense, and the people I talk to just get it.”

It is perhaps unsurprising that the concept of Let Them Eat Dirt initially arose from the mother within the partnership.

“Marie-Claire did the experimental work,” says Brett. “She’s a young mother with young kids, and had spoken to other mothers who were all very interested in this, so she suggested we might write a book.”

Dr. Arrieta’s research revealed that children lacking certain intestinal microbes—especially within the first five years of life—will be prone to developing asthma. This and other ground-breaking discoveries triggered Let Them Eat Dirt, a book set to make waves not only in its scientific field, but also find a place on the bookshelf of parents.

While Let Them Eat Dirt concerns the importance of microbiota at the beginning of life, Brett is already working on a second book which examines how even in our twilight years we can take measures to ensure our microbes still impact our health in positive ways.

“I swore I would never write another book, but I’m now writing this new one with my daughter, who has a PhD in Gerontology (and Geography),” says Brett. “This is about the other end of life, looking at everything from skin wrinkles to how, if you brush your teeth three times a day, it leads to a big decrease in Alzheimer’s disease, and other stunning stuff. It’s a head-to-toe look at how to age healthily with your microbes. So, being the two times your microbes change the most, I guess Let Them Eat Dirt and the new one, when published, will represent the bookends of life!”