Let Them Eat Dirt is a new parenting book written not by child psychologists but by two microbiologists, Marie-Claire Arrieta and Brett Finlay. Their aim is to encourage parents to ease up on hygiene. Children, they say, should be outside more, playing in the mud and coming into direct contact with the natural world.
Of course, the authors are not suggesting that parents abandon all hygiene, in particular washing their hands after using the loo or interacting directly with someone who has a cold. Their argument is instead about our current total aversion to dirt. Arrieta and Finlay believe this is playing havoc with our health, and may be responsible for the surge in a number of chronic non-infectious diseases such as asthma, allergies, autoimmune diseases, and even possibly obesity and coeliac disease.
The scientists base their advice on research into microbes in the human gut. While our ability to destroy harmful microbes with antibiotics, vaccines and sanitation has brought about a revolution in the treatment of infectious diseases, these procedures do not discriminate, so the beneficial microbes, which allow our immune system to develop, are also destroyed.
Whenever a child's immune system encounters a (new) harmless microbe, it learns how to ignore it, or at least to tolerate it. If a growing child has exposure only to harmless microbes, the authors say, their immune system will remain immature.
It would take considerable medical expertise to know whether Arrieta and Finlay's hypothesis is correct, but the scientific evidence they cite makes it worthy of careful consideration. Furthermore, their argument is appealing psychologically, for the following reasons:
- Spending time outside encourages the production of endorphins, our natural painkillers that trigger feelings of wellbeing.
- Being outdoors helps set our biological clock and promotes more restful sleep.
- Owning a dog - another factor the authors argue boosts immune system development - teaches nurturing skills.
- Petting a dog releases oxytocin, the hormone that helps us feel safe and secure, and walking it encourages the whole family to take more exercise.
- Playing with natural materials stimulates creative power, because children are more likely to choose how to use natural objects, as opposed to reacting uniformly to ready-made toys and screen instructions.
- Playing outside in nature instils a respect for - and love of - the environment.
If that's not enough, think about the time you'll save when you're not cleaning and sanitising. Instead, you can use that time to have fun together as a family.
Linda Blair is a clinical psychologist. Her book is The Key to Calm