When my daughter was seven, we spent three weeks trekking around the Khumbu region of Nepal. That meant three weeks with no running water, no showers, and very limited handwashing opportunities. Unlike my daughter, I did not revel in our sustained lack of hygiene. (“I’ve never been this dirty for this long!” she would enthuse daily.) But looking back, I realize all that dirt probably may have done us more good than harm. 

For years, researchers have found evidence to support the idea that getting our hands dirty —say, in the soil of your backyard raised beds — on a regular basis can have myriad health benefits. It’s a lesson, however, that can be hard to reconcile with our lingering, pandemic-induced germaphobia (not to mention a childhood of being ordered to wash our hands before dinner). Of course, there’s a big difference, germ-wise, between digging in your garden and picking up your sick kid’s used tissues. Exposing yourself to the power of the bacteria found in “good dirt” may be key to staying healthy.

Before we became a culture of shoe-wearing indoor-dwellers, humans spent a lot of time in direct contact with nature. Our ancient ancestors were skin-to-skin with dirt on a daily basis. They walked barefoot, interacted with wild animals, and ate food pulled directly from the ground. 

Some argue that in our modern culture, the pendulum has swung too far in the other direction. We’ve done all we can to separate ourselves from the natural world and over-sanitized our limited interactions with the outdoors. Scientists developed a theory about this called “the hygiene hypothesis.” The gist being that, in our quest to rid our lives of unhealthy bacteria, we may be unintentionally missing out on the thousands of good bacteria in the environment.

Next, consider that the bacteria in your digestive system make up the environment known as the gut microbiome, which is closely linked to an array of bodily functions. A healthy microbiome is important for maintaining the health of your immune system, reducing inflammation, regulating your metabolism, and stimulating neurotransmitters that send signals to the brain. Not surprisingly, an unhealthy microbiome can increase your risk of numerous conditions including obesity, inflammatory bowel disease, atherosclerosis, and mood disorders.

A certain type of microbe that our gut needs, called spore-forming organisms, is especially plentiful in soil and the environment. “These bacteria play a crucial role in expanding the regulatory arm of the immune system,” says Graham A.W. Rook, MD, emeritus professor of medical microbiology at University College of London. “They act as a sort of military police to stop inappropriate immune responses, such as attacking our own tissues, digestive system, or harmless foods and allergens.” 

Turns out, the more exposure you have to these helpful bacteria in the environment (especially in the first few years of life), the more robust your immune system becomes. Studies have looked at the “farm effect,” namely how early interactions with soil, farm animals, and even house pets can boost your microbiome and your immune system. Studies have shown that kids who grow up around animals have lower rates of asthma and allergies.

Even people who didn’t grow up on farms can reap benefits from exposure to more of these health-enhancing environmental organisms. A study in Finland found that adding soil and material from the forest floor to urban daycare environments increased the diversity of the children’s skin microbiomes. “It also enhanced the regulatory arm of the immune system, showing that the immune system benefits from contact with a wide variety of environmental microorganisms,” says Rook. 

The spore-forming, immune-boosting bacteria in our gut fluctuate over time. But if they’ve been lost — due to poor diet or taking antibiotics — “they can be reinstalled by encountering them again in the environment, mainly through contact with soil,” says Rook.

To get a dose of dirt near you, participate in a mud run, sit on the ground in the park instead of on a bench, or volunteer at a local community garden. Or step into your yard: Gardening without gloves can be a fast-track to the health benefits hiding in its soil.