Can Dirt Benefit Developing Children?
by Lisa DiFalco
Could parents be undermining the development of children’s immune systems by keeping children and the objects they encounter too clean? With the proliferation of hand sanitizers and the recommendation to wash hands frequently, it appears that we may be doing the body more harm than good.
To a certain degree, developing bodies need germs and benefit from the microbes found on the body and around the immediate environment. This idea supports the “hygiene hypothesis,” a belief that when children have limited early exposure to viruses, bacteria and parasites, they are at greater risk of developing asthma, allergies and autoimmune diseases in later life. Children with lower rates of allergies are often those that live on a farm, go to day care at an early age or have older siblings.
A growing body of research, including a study published in the New England Journal of Medicine and a book looking at how dirt may benefit the development of a strong immune system, all point to the idea that exposure to certain germs and animals can support immune system health.
Can a little dirt actually help a child avoid developing allergies, asthma or other conditions later in life? Learn more about the relationship between dirt and immune system health.
Is it necessary to sanitize the home environment?
If the cookie falls, a child can still eat it. Let a family dog lick a child’s face. Pick up that pacifier, lick it and stick it in a child’s mouth. It finally sounds like parents can relax a bit and allow germs and microbes to come into contact with their children’s immune systems. According to research, stimulating the immune system with germs, microbes and dirt may benefit a child’s development in a myriad of ways. Thom McDade, Ph.D., associate professor and director of the Laboratory for Human Biology and Research at Northwestern University, said, “We’re moving beyond this idea that the immune system is just involved in allergies, autoimmune diseases, and asthma to think about its role in inflammation and other degenerative diseases. Microbial exposures early in life may be important … to keep inflammation in check in adulthood.”
Many microbes have lived with us over the millennia, but a noticeable change has occurred in the last 50 years. It appears that important microbes may be disappearing from human guts. Martin Blaser, M.D., professor of internal medicine at New York University, said, “These [microbes] perform important physiological functions but because of modern life they are changing and some are disappearing. Those disappearances have consequences — some good, some bad.”
Some now believe that rather than protecting infants from illness, overly sanitizing home environments can result in the development of weaker immune systems. McDade says, “I’d like to see a recalibration toward common sense. You don’t have to wash or sanitize everything.”
How dirt may foster a stronger immune system
Jack Gilbert, a father of two children who studies microbial ecosystems at the University of Chicago and co-authored the new book Dirt Is Good: The Advantage of Germs for Your Child’s Developing Immune System, wanted to know the risks associated with the germs that children commonly encounter. Gilbert said, “It turned out that most of the exposures were actually beneficial. So that dirty pacifier that fell on the floor — if you just stick it in your mouth and lick it, and then pop it back in little Tommy’s mouth, it’s actually going to stimulate their immune system. Their immune system’s going to become stronger because of it.”
He feels that one of the things that parents get wrong is not introducing important microbes to a child by overzealous cleaning of the environment. Gilbert shared:
“Some of the main things are over-sterilizing their environment, keeping their children from ever getting dirty. So going out into the backyard and playing in the mud, and then as soon as they’re filthy, bringing them in and sterilizing their hands with antiseptic wipes, and then making sure that none of the dirt gets near their faces. Also, keeping them away from animals. The dogs and cats, sure, but also, other animals. It’s fine to wash their hands if there’s a cold or flu virus around, but if they’re interacting with a dog, and the dog licks their face, that’s not a bad thing. In fact that could be extremely beneficial for the child’s health.”
Gilbert believes allergies may be an unintended result of parents trying to protect children from germs and dirt too much. When neutrophils are not given something to do, the immune system will become hypersensitive to any foreign bodies introduced. When such neutrophils come into contact with pollen or another foreign body, it triggers an overly inflammatory reaction. Asthma, eczema and some food allergies result from this situation, according to Gilbert.
Gilbert was involved in a study comparing children who helped with the care of farm animals with those who did not. This 2016 New England Journal of Medicine study compared Amish children and Hutterite children. The Amish children who helped with caring for farm animals had seven times less risk of developing asthma when compared to the Hutterite group, who did not work with farm animals. Researchers believed exposure to barnyard bacteria and viruses was the factor responsible for the difference.
Parents can support their developing children’s immune systems by exposing children to beneficial germs by visiting a farm or getting a dog, eating a diverse array of veggies and fermented foods, and avoiding antibiotics unless absolutely necessary. New findings also do not mean that parents should never clean their children or the immediate environment. It is still a recommended practice to clean surface areas and tools used to prepare poultry, meat and eggs when finished to avoid exposing children to dangerous bacteria such as salmonella. Parents, caregivers, educators, health care professionals, behavioral analysts and nutritionists can benefit from the growing research touting the benefits of dirt, germs and microbes.