Maya Shetreat-Klein, MD, is an integrative pediatric neurologist and an herbalist, naturalist, urban farmer, and author of The Dirt Cure: Growing Healthy Kids with Food Straight from Soil. Dr. Shetreat-Klein encourages children and adults to spend time outdoors, eat healthy food, and embrace the elements of fresh air, soil, sunshine, and water. She founded the Terrain Institute in New York City, where she educates parents, teachers, healers, and health care providers about Terrain Medicine.
Food Tank (FT): How did you become interested in the interplay between the microbiome, the food we eat, and our health?
Maya Shetreat-Klein (MSK): It started with my own son’s health problems. He suddenly developed asthma symptoms on his first birthday, which persisted almost continuously for ten months. At that time, he also experienced a developmental plateau. He was given a continuous array of antibiotics, inhalers, and steroids, though no doctor seemed to find this sudden shift—from wellness to sickness—of any concern. Ultimately, he was found to be severely allergic to soy. When we removed soy from his diet, his asthma stopped within three days. But at that point, his gut microbiome had been decimated by the medications he had been taking almost continuously for the better part of a year. For that, I had to do my own research to determine how to help him to heal. In the process, I discovered that soy in the United States was not as healthy as I had thought and that most of it was genetically modified (GM), doused in Roundup, and processed. The journey of my son’s healing was the beginning of a whole new education about farm, food, soil, and seed, about pharmaceuticals and the medical system, and about how to reclaim our health. The silver lining was that I then applied all of this knowledge to the patients in my practice, with huge success.
FT: Can you expand upon the title of your book, The Dirt Cure?
MSK: Dirt represents three things: being exposed to microbes, eating fresh, unprocessed food from healthy soil, and bonding with nature. Many children come to see me suffering from chronic illnesses, such as ear infections, allergies, and autoimmune diseases, as well as attention-deficit/hyperactivity disorder (ADHD), autism, seizures, and headaches. Rather than medicate them, I wanted to understand the root cause of these problems and figure out how to prevent or reverse them. These aspects of dirt are the foundations of robust, lifelong health and well-being.
FT: How does a robust microbial community in the soil translate into healthy food?
MSK: Soil impacts our health through the food we eat. Most of us know that the nutrients from rich soil become part of plants, and then become part of us when we eat either plants or the animals that consume those plants. Most people do not realize how microbes, and even pests, influence the health of our food. Plants have immune systems just as we do. When challenged by microbes and bugs, these immune systems double down on defense by producing innate phytonutrients—the stuff of superfoods—for protection. The greater the challenge, the more they produce. Conversely, plants that grow in depleted, sanitized soil are far more vulnerable to disease or failure, partly because they lack resources to respond effectively. In fact, several studies have shown that vegetables grown organically are higher in phytonutrients and more resistant to drought than those grown with pesticides. And wild plants, exposed to the elements with no help from humans, must become so resilient that they are virtually bursting with phytonutrients.
The phytonutrients—the compounds that make cranberries red, lemons fragrant, and coffee bitter—make our food both delicious and healthy for us. For instance, receptors that bind bitter compounds found in coffee or dark chocolate line not just our mouths but our entire digestive and respiratory tracts, including the nose, throat, and lungs. They then improve gut motility, regulate blood sugar levels, and help us to fight infections, staving off coughs, colds, strep throat, and flu. But these kinds of compounds don’t develop in isolation. Rather, they are the result of a conversation—indeed, a challenge—between plants and us, and between plants and their terrain.
FT: Why are food allergies and autoimmune diseases so prevalent today?
MSK: We’ve known for some time about the hygiene hypothesis, which states that children who grow up on farms develop fewer allergies and have less asthma because they are dirtier. When researchers investigated, however, they found that an urban apartment has roughly the same number of microbes as a farm. The difference was that the microbes on farms were far more diverse. Our immune systems like this because they are actually very social, and benefit from meeting and greeting all sorts of compounds every day. When their interactions are limited, they begin to attack things that they shouldn’t, like food, pollen, or even our own bodies. Although we think to avoid bacteria, viruses, and other organisms, data suggest that exposure may well be critical, not just to prevent allergies and autoimmune diseases but even conditions like cancer. Ultimately, nature provides us with the biodiversity we need to be healthy. Consider that in just one teaspoon of soil, there are as many organisms as there are people on the planet! This kind of exposure is what our bodies crave.
FT: What would you say is the best method of encouraging children to spend more time outdoors and exposed to dirt, and less time indoors?
MSK: Children are incredibly observant. They are far more likely to notice and imitate what you’re actually doing than to follow what you’re telling them to do. Spending time together in nature, as a family, creates a familiarity with being outdoors, which a surprising number of children these days finds intimidating. It also provides opportunities for lifelong family memories. Keep in mind that not all memories have to be perfect. While it’s lovely to have the picture-perfect moments, working through the challenges together can feel just as valuable.
Sometimes parents can find it hard to think of things to do. But often, you don’t have to plan structured activities because many kids will start to explore naturally and interact with nature if you give them the opportunity to do so. Sometimes they can lead the way for you! There are countless wonderful activities to choose, from hiking or biking to building forts, teepees, or bonfires. Kids love to plant seeds or pick out seedlings to plant, and they can be quite nurturing and proud of their plants! Another fun activity can be to use guidebooks, or even apps on smartphones, to identify birds, leaves, trees, or mushrooms. Finally, geocaching can be a great way to combine technology and nature to engage older kids and teens. It’s a huge, international digital scavenger hunt, in which participants use a Global Positioning System (GPS) receiver or mobile device, and other navigational techniques, to hide and seek containers outdoors, called geocaches, anywhere in the world.
FT: Most of us remember being told as children to stop playing in the mud and to clean up, but what positive impact can getting dirty have on children’s immune systems?
MSK: Believe it or not, soil is filled with health benefits. Diverse microbes that live in soil interact with our bodies and brains in surprising ways that keep our immune and nervous systems in balance. For example, Mycobacterium vaccae is one organism that boosts serotonin levels in the brain to levels similarly achieved by pharmaceutical antidepressants. In animal studies, mice exposed to M. vaccae could navigate difficult mazes twice as quickly, with half the anxiety as control mice. Regular forest bathing, or immersion in the beauty of a forest, has been shown to boost focus and mood, lower levels of stress hormones like cortisol, and increase anti-cancer proteins. Time in nature also makes us feel happier and smarter. There are many likely components that explain why nature makes us feel so good. From the microbes that boost our mood to the vitamin D we get from spending time in the sun, there are several physical components. But there are also spiritual components. Nature inspires feelings of awe, beauty, and wonder. Studies have shown a correlation between feelings of awe and lower levels of cytokines, inflammatory markers that result from the immune system being on high alert. While inflammation can be important for fighting infection when the body is presented with a specific threat, chronically high levels of cytokines have been linked to a number of health problems, including asthma, allergies, inflammatory bowel disease, and even ADHD.
FT: What is your philosophy on food?
MSK: I believe that we must recognize the sacred nature of our relationship with the food we eat and the water we drink. Indeed, food—and the terrain where it is grown—is our most intimate interaction with nature because it literally becomes a part of us. We must remain grounded in this knowledge, and care for our food—and the people who grow it—and our terrain as we would ourselves or our families.
FT: What do you grow in your home garden?
MSK: Everything. I live in New York City, but I like to push the boundaries to prove what is possible. I keep hens. I grow food, from a cruciferous section of cabbage, collards, kale, and kohlrabi to a nightshades section of cucumbers, potatoes, and tomatoes. I have a raspberry patch, a strawberry patch, and elderberry bushes, as well as cold-hardy kiwis and concord grapes. This year, I have a vast amount of fennel and sunflowers that self-seeded all over from last year. I also grow medicinal herbs and make teas, tinctures, and oils from them. Finally, I try to take advantage of what grows wild, and some of that is just being aware of what’s growing in my yard that is edible or medicinal. We mow the lawn infrequently and make sure to forage red clover flowers, violets and their leaves, dandelion greens and their roots, wild strawberries, curly dock, wineberries, and others.
FT: How can Food Tank readers spread awareness about the importance of the dirt cure where they live?
MSK: I wrote The Dirt Cure so that people could have an easy-to-read, evidence-based reference with plenty of take-home points to share with family members, teachers, school administrators, health care providers, and officials. I included more than 700 references so that the science would be accessible. Beyond the book, many steps to the dirt cure are relatively simple. Learn where your food comes from. Support growers by getting a Community Supported Agriculture (CSA) share or buying from farmer’s markets. If that's not possible, I’m happy that Supplemental Nutrition Assistance Program (SNAP) dollars make it more accessible to all. Aim to buy pastured animal products and lots of in-season, organic produce. Grow some of your food, whether in a windowsill container, a plot in a community garden, or a patch in your yard. Compost, so you feed your soil instead of landfills. Get outdoors every day, whether it’s to walk your dog, take a hike in the woods, play frisbee, or picnic in a local park. Encourage your child’s school to increase time outdoors through nature curricula, prolonged recess time, and picnic lunches. The dirt cure should be part of a joyful life that helps people to feel happy, healthy, and complete.
Click here for more information about Dr. Shetreat-Klein's work.