Mounting research on the human microbiome continues to point to the impact of our resident microbes on both our short- and long-term health. Though you can’t see them, trillions of these little critters live in your gut and on your skin, and play important roles in everything from regulating your mood to chronic diseases like diabetes and arthritis. One of the ways we shape our microbiome is through exposure (or lack thereof) to the microbes in soil. No pricey supplements needed (though there are now some made from soil-based microbes), just some good old fashioned time in the dirt may help you reap some impressive health benefits.
Dirt Can Strengthen Your Immune System
Numerous studies have pointed to the decreased incidence of allergies and asthma when children are exposed to a variety of microbes. Often called the ‘farm effect’, researchers postulate that in our overly-sterilized modern world, developing immune systems don’t encounter enough bugs to learn how to regulate properly. Others have found evidence that there’s an exchange of DNA between soil microbes and those in our gut that positively affects immune function.
Digging in the dirt exposes us to many of these microbes, which get on our skin and into our respiratory tract as we poke around in the soil. They can also hitch a ride on those yummy garden veggies we’re cultivating. Jeff Leach, founder of the American Gut Project, encourages us to “dirty up” our diets and suggests that the impoverished modern human microbiome would be far more capable of keeping us healthy if our food was less sterile. If you’re growing your own food or buying from local organic farms, Leach suggests you might scrub your produce a little less thoroughly to get a healthy dose of dirt in your gut.
The vitamin D we absorb from the sun while we dig in the dirt also plays a critical role in a healthy immune system, as does the gentle exercise and stress relief we experience when we garden. The British National Health Service (NHS) has even recommended that doctors prescribe gardening for its health-boosting effects!
Getting Dirty For Better Mental Health
Getting dirty may also make you happier and less stressed. Some studies suggest this effect originates in the gut, where beneficial soil microbes help regulate neurotransmitters that affect our emotional state. When the soil bacteria M. vaccae were given to cancer patients, they reported improvements in mood. Later studies in mice suggested this effect was a result of increased serotonin production caused by the bacteria.
Others have pointed to the stress-relieving properties of gardening, which may come from simply being in nature, from the gentle exercise gardening encourages, or from the satisfaction we derive from nurturing plants and growing our own food. Time spent in nature has repeatedly been shown to improve health and mood. In one study, hospital patients with views of trees healed more quickly and reported less pain than patients with views of brick walls.
Whatever the cause, the cortisol-lowering effect of a stress-relieving dirt session is a healthy thing. Cortisol — produced when we’re under stress — has been linked to an array of undesirable health effects, from weight gain to poor sleep to decreased longevity. Finding ways to reduce cortisol is a smart move.
If you’re looking for a pick-me-up, digging in the dirt might be just what the doctor ordered.
In addition to the microbial wonders of soil and other health benefits of gardening, research suggests that contact with the ground may have additional benefits deriving from the free electrons available on the earth’s surface. Through most of human history, our ancestors walked barefoot and slept on the ground, with perhaps a conductive animal skin between their bodies and the earth. Now our rubber-soled shoes, our cars, and our homes all insulate us from what may be some profound therapeutic effects of contact with the soil. When was the last time you walked outside barefoot?
The electrical charges of the earth appear to do some important work for our bodies by neutralizing what are popularly known as free radicals. (If you want to be technical, they’re ‘reactive oxygen species’, or ROS.) In a 2012 meta-study published in the Journal of Environmental and Public Health, researchers reported:
“Mounting evidence suggests that the Earth’s negative potential can create a stable internal bioelectrical environment for the normal functioning of all body systems. Moreover, oscillations of the intensity of the Earth’s potential may be important for setting the biological clocks regulating diurnal body rhythms, such as cortisol secretion.”
By neutralizing free radicals, “earthing,” or grounding ourselves to the earth’s surface, may reduce inflammation, which is currently thought to play a critical role in a number of chronic diseases. In one study, participants slept on a device called an ‘earthing mat’, which was grounded to the earth with wire. Subjects sleeping on grounded mats reported significantly less pain and better sleep quality than the control group, who slept on a mat that they were told was grounded to the earth but actually wasn’t. Another study found that sleeping on an earthing mat lowered measurements of cortisol, a stress hormone that disrupts sleep and saps energy.
One study mimicked the exposure to the earth with grounded foot patches, and used biofeedback and EEGs to measure subjects’ electrophysiological responses. Earthed subjects showed significant drops in measures of stress and muscular tension while hooked up to the grounded patches as compared to the control group.
These were small studies, and skeptics abound about the benefits of grounding. But there’s little harm in taking off your shoes and going barefoot in the grass a bit each day and seeing if you notice any effect.
The data on the health benefits of time in the dirt is promising. If you want to boost your immune system, reduce stress, sleep better and have more energy, try getting out and getting dirty!