In their new book, Let Them Eat Dirt: Saving Your Child from an Oversanitised World, microbiologists B. Brett Finlay and Marie-Claire Arrieta reveal the recent explosion of scientific knowledge, and undeniable evidence, that our compulsion for hyper-cleanliness is having a negative effect on our children’s lifelong health. S4K quiz the authors on the book that may change your entire perspective on what it means to be clean…
Interview by Nadia Duncan
Q) After giving birth we are told to sanitise everything – from dummies to bottles. What is the ‘magic’ age at which a bit of dirt becomes beneficial?
We were really surprised when we learned that the American Academy of Pediatrics no longer recommends sterilising dummies or bottles for babies of any age. It only recommends a stovetop method (cleaning them in boiling water) the very first time they are used or if the water used at home is not deemed as safe drinking water. If the water is safe enough to drink, it is also safe enough to use to clean bottles and nipples. The same goes for any utensil or plates used to feed babies solid foods, and for pacifiers and teethers – washing them with soap and water is enough. However, be aware that milk bottles and nipples need to be washed properly as milk residues can get trapped in the bottle nooks and crannies where bacteria can flourish, so a baby bottlebrush is a good idea for a proper wash.
Q) Do you think parents have been over-sold the idea of protecting our children with cleanliness by companies trying to sell us products?
It probably goes even a step before that. Scientists and doctors have been mostly studying the microbes that cause disease for the past century and a half. So most of the stories that people hear in the news are about how microbes are dangerous. It is only natural that the commercial markets make products that they know people will consume. Since society has been promoting cleanliness and sees microbes as an imminent danger, it’s only natural that we see all these antimicrobial products in the market nowadays.
Q) Can you briefly explain why an imbalance in microbes can lead to some of the childhood health problems you discuss in the book such as asthma, autism, obesity and diabetes?
Microbes carry out essential tasks in our bodies during the first few years of life. They are essential for the maturation of our immune system. Without this proper maturation our immune system becomes sloppy and unable to perform its central task – to differentiate a friend from a foe. Our microbiome is a key decision-maker in our energy metabolism and how fats in our body are used or stored. Given what they do for us, it is not surprising that missing out on the right kind of microbial exposure early in life is being associated with immune disorders (such as asthma, allergies and inflammatory bowel disease) and metabolic diseases (such as obesity and diabetes). These diseases are, to a great extent, a consequence of relatively recent changes in our lifestyle – modern diet, oversanitisation, excessive use of antibiotics that have altered our microbiome early on.
Q) Many homes have a family pet – some believe letting a dog lick a wound or cut is a good idea but they do stick their noses in unpleasant places. What’s the rule when it comes to cleanliness, children and animals?
If the dog is healthy and gets periodic veterinary care it is safe to allow it to be close to children, as close as licking them. We do not advocate the licking of wounds (there no scientific data on it), but having pets around the house reduces the risk of allergies by about 13 per cent.
Q) One of the most common concerns parents worry about is toilet hygiene and regular hand washing, particularly with younger children. Is this the same thing or does any of your advice contradict the health and safety messages we are given from the NHS or our GPs?
No, our message is that hygienic practices aimed to prevent diseases are as necessary today as they were 100 years ago. We should be washing our hands after using the bathroom, before making or eating food, if we have been in a very crowded place (train station, shopping mall, etc.), if we have been in contact with a sick person or if we have been around animal waste. But beyond that, we should allow kids to be kids, get dirty and not clean them at the first speck of dirt because dirt does not equal disease. Hand washing should be promoted at the times where it is known to reduce the spread of disease, but it is not necessary for other times.
Q) If you had to give any parent a top three do and don’ts for a healthy child – what would they be?
Let them play with dogs. Feed them a fibre-rich diet as early as they start eating solids (whole grains, vegetables and fruits in every meal). Supplement with fermented foods (yogurt, kefir, sauerkraut, etc.). Reduce sugar intake. Be smart about antibiotics. Restrict their use only when necessary and talk to your doctor about this. Antibiotics are currently overused.
Let Them Eat Dirt: Saving Your Child from an Oversanitised World is published by Windmill. Paperback £12.99 and also available as an eBook.