When my first child began to crawl, I bought a steam floor cleaner that promised to kill germs.  I would religiously steam clean the floors every couple of days, but with multiple pets and country living, there was no real way to make my home germ-free (thankfully). Turns out we need not be afraid of dirt, according to the Hygiene Hypothesis.  In fact, dirt cures!

Photo credit: Hypnotica Studios Infinite via Foter.com / CC BY

Dirt is good for you!   Natural dirt from the garden, the forest, the beach helps our immune systems develop.  I’m not talking about the dirt from city streets ladened with oil and chemicals or from lawns and parks sprayed with pesticides and herbicides. Let your kids play in the dirt!

Remember making mud pies?  We played in the dirt as children.  We had picnics by the river with no hand sanitizer.  We had healthy immune systems.  Let your kids play in the dirt!

Dr. Maya Shetreat-Klein, a pediatric neurologist in New York, advocates for a “Dirt Cure”.  Dr. Klein explained to the New York Times:

Dirt means three things to me. It’s eating nutrient-dense food from healthy soil. It’s being exposed to certain microbes. And it’s spending time outdoors in nature.((http://well.blogs.nytimes.com/2016/02/11/how-the-dirt-cure-can-make-for-healthier-families/?em_pos=small&emc=edit_hh_20160212&nl=well&nl_art=11&nlid=48748113&ref=headline&te=1&_r=0))

What is the Hygiene Hypothesis?

Dr. Gallo of the University of California at San Diego explains:

The so-called “hygiene hypothesis,” first introduced in the late 1980s, suggests that a lack of early childhood exposure to infectious agents and microorganisms increases an individuals susceptibility to disease by changing how the immune system reacts to such “bacterial invaders.”

“These germs are actually good for us,” said Richard L. Gallo, MD, PhD, professor of medicine and pediatrics, chief of UCSD’s Division of Dermatology and the Dermatology section of the Veterans Affairs San Diego Healthcare System.((http://eyr.lil.mybluehost.me/2009/12/21/hygiene-hypothesis-proven-true-dirt-is-naturally-good-for-kids/))

We’ve written on the Hygiene Hypothesis on several occasions.  It’s one of our favorite topics in this world full of hand sanitizer and antimicrobial socks.

1. Hygiene Hypothesis Proven True: Dirt is Naturally Good for Kids

2. Hygiene hypothesis linked to heart disease prevention

3. Let Them Eat Dirt (Or, Free Yourself From Hand-Washing Guilt)

4. Reduce your child’s asthma risk…get a dog (study)

Most of what we have learned about the power of dirt and the Hygiene Hypothesis has to do with exposure in early childhood.  Dr. Klein’s ideas about dirt curing give hope that it is never too late to get the benefits of living close to nature and eating nutrient rich food.

Photo credit: Theophilos via Foter.com / CC BY-NC-ND

Here is more from her New York Times interview:

We used to think that children who grew up on farms were healthier than children in urban environments because they were exposed to more microbes. But studies have found that the number of bacteria in urban environments and on farms is similar. The difference is the diversity of the bacteria. Microbial diversity seems to have a very powerful impact. Children’s immune systems are very social: They like to meet and greet a lot of things. It seems the more they meet and greet, the more likely they are to be in balance, and the less likely they are to let any one microorganism grow out of control, as occurs with infection.

Q.

What is the microbial diversity like in soil?

A.

In one teaspoon of soil there are more organisms than there are humans on our planet. Soil houses about 25 percent of the world’s biodiversity. What we also know from studies is that when children spend time in green environments – in natural playgrounds, for example, or in parks and forests – they perform better on standardized tests, they’re more creative, they’re happier and their cortisol levels are lower, so they’re calmer and less stressed. And I think that might be somewhat related to the kind of organisms they’re exposed to when they’re playing outdoors.((http://well.blogs.nytimes.com/2016/02/11/how-the-dirt-cure-can-make-for-healthier-families/?em_pos=small&emc=edit_hh_20160212&nl=well&nl_art=11&nlid=48748113&ref=headline&te=1&_r=0))

Research proves that nature is good for our children!

What is really interesting about Dr. Klein’s work is she relates the organisms plants are exposed in the soil to our health.  When we strip the soil of these organisms through agri-chemicals, we are robbing our own bodies of the full benefit of the food we eat.

The organisms in soil have an impact on the health of our food. Part of what makes fruits and vegetables good for us is the phytonutrients in them – the things that make cranberries red or coffee bitter. Phytonutrients are part of the plant’s immune systems. Organisms in the soil that we might think of as pests actually stimulate plants to make more phytonutrients. So these small stressors actually in a sense enhance our health. Being exposed to different organisms improves the health of the plant and it improves our health as well.((http://well.blogs.nytimes.com/2016/02/11/how-the-dirt-cure-can-make-for-healthier-families/?em_pos=small&emc=edit_hh_20160212&nl=well&nl_art=11&nlid=48748113&ref=headline&te=1&_r=0))

Photo credit: PHOTO/arts Magazine via Foter.com / CC BY

It’s not just about the exposure to dirt in nature that makes kids healthier, it is eating food that is grown in healthy soils.  Research has shown that organic food is more nutritious than conventionally grown crops. The Institute of Food Technologies (IFT) at Rutgers University supports Dr. Klein’s ideas about plant stressors creating higher quality food:

Two major hypotheses explaining the possible increases in or- ganic acids and polyphenolics in organic versus conventional foods have been proposed. One hypothesis considers the impacts of differ- ent fertilization practices on plant metabolism. In conventional agri- culture, synthetic fertilizers frequently make nitrogen more avail- able for the plants than do the organic fertilizers and may accelerate plant growth and development. Therefore, plant resources are allo- cated for growth purposes, resulting in a decrease in the production of plant secondary metabolites (compounds not essential to the life of the plant) such as organic acids, polyphenolics, chlorophyll, and amino acids.

The second hypothesis considers the responses of plants to stressful environments such as attacks from insects, weeds, and plant pathogens. It has been argued that organic production methods—which are limited in the use of insecticides, herbicides, and fungicides to control plant pests—may put greater stresses on plants and may require plants to devote greater resources toward the synthesis of their own chemical defense mechanisms. Increases in antioxidants such as plant polyphenolics have been attributed to their production in plant defense (Asami and others 2003), al- though the same mechanisms may result in the elevations of other plant secondary metabolites that may be of toxicological rather than nutritional significance.((http://eyr.lil.mybluehost.me/2012/03/15/organic-vs-conventional-is-the-proof-is-in-the-nutrition/))

Dr. Klein advocates children should spend more time outside.  She believes schools should have more nature-based outdoor curriculum.  I can’t wait to read her book The Dirt Cure: Growing Healthy Kids with Food Straight from Soil.