EarthTalk®

Dear EarthTalk: A friend recently told me that when her family stopped using hand sanitizer and antibacterial wipes all the time, they stopped getting sick so much. Is there any research backing up this theory, or is it just a “new” wives tale? -- Betsy Edger, via e-mail

Your friend may be onto something. The so-called “Hygiene Hypothesis”—first put forth by British epidemiologist David Strachan in a 1989 paper in the medical journal Thorax—suggests that a lower incidence of infection during early childhood (thanks to more sterile, less crowded environments as compared to earlier times) could explain the rapid rise in allergic diseases in the late 20th century. As the theory goes, in the modern world our immune systems no longer have to deal with the vast numbers of potential real pathogens we experienced during the previous stages of our evolution. With so much more time on their hands, our antibodies rise up against other perceived dangers—gluten, peanuts, milk—which in fact are not really threatening. Our immune systems’ over-reaction manifests itself in the form of pesky and occasionally life-threatening allergies.

And the research does seem to bear out the hypothesis. A 2003 Australian study concluded that asthma and allergy rates are higher for those who move from a developing country to a developed country. Meanwhile, a 2007 study by a group of international researchers at the Centre for Research in Environmental Epidemiology found that “frequent use of common household cleaning sprays may be an important risk factor for adult asthma.” And a 2011 study by German researchers found that children living on farms—and therefore exposed to a wider range of microbes than their urban and suburban peers—had statistically significant lower asthma rates.

Yet others, like University College London researcher Graham Rook, think there’s more to the story. He attributes rising rates of inflammatory and other human allergic disease not to modern-day hygiene but to lack of exposure to so-called “old friends”—microbes present in hunter-gatherer times when human immune systems were evolving. Rook backs up his “Old Friends Hypothesis” by citing other studies shedding light on the connection between good health and exposure to greater biodiversity in general.

“Lifestyle changes, antibiotics, caesarean births and lack of breast-feeding limit the transmission of maternal microbiota to the next generation,” says Rook, adding that our “unvarying diets” lacking the microbial diversity our bodies evolved with combined with our limited contact with the natural world only aggravate the problem. “Without these microbial inputs in early life our immune systems, endocrine systems and metabolic systems do not develop correctly, and can malfunction.”

The moral of the story? Whether you agree more with Strachan or Rook, don’t be scared to indulge in nature and don’t be a germaphobe. Get your kids off their screens and out into the yard, park, playground or beach where they can mingle with the dirt and get exposed to as many different microbes as possible. They’ll live healthier lives and handle future health threats more easily than those who spend their childhoods over-sanitized indoors. Chances are they’ll be happier adults, too, given the research correlating lack of outdoor time with increased rates of depression. Who would’ve thunk that dirt cures?

CONTACTS: Migration and Asthma, onlinelibrary.wiley.com/doi/abs/10.1002/ppul.10323; Household Cleaning Sprays & Adult Asthma, www.ncbi.nlm.nih.gov/pmc/articles/PMC2020829/; Environmental Microorganisms and Childhood Asthma, www.nejm.org/doi/full/10.1056/NEJMoa1007302; Graham Rook, www.grahamrook.net.

Dear EarthTalk: Are any environmental groups working specifically to increase access to nature and the outdoors? -- Mary Pelletier, Macon, GA

No one doubts that time spent outdoors in nature is time well-spent, especially in this age of smartphones, tablets and laptops vying for our attention. Research consistently shows links between higher levels of health and well-being when people have access to parks, gardens, greenways and other natural areas.

According to the Children & Nature Network, time spent in nature gives kids a wide range of benefits including reduced nearsightedness, increased Vitamin D levels, reduced risk of obesity, improved relationship skills, and reduced levels of stress, anger and aggression.

And it’s not just kids who benefit. “Access to nature has been related to lower levels of mortality and illness, higher levels of outdoor physical activity, restoration from stress, a greater sense of well-being, and greater social capital,” reports the non-profit American Public Health Association. The group is working to convince public health practitioners and health professionals to step up efforts to get more Americans, young and old, off their screens and outside to experience the physical and emotional benefits of breathing fresh air and enjoying the sights and sounds of the natural world.

Meanwhile, the Sierra Club launched its Nearby Nature campaign in 2017 to help build “a more equitable, just and inclusive movement by increasing access to the outdoors.” The program engages youth and communities to explore, enjoy and protect parks, waterways and natural spaces in and around urban areas.

“Communities that have been historically underrepresented in the environmental movement are often the same communities that experience limited access to nature and face the greatest economic, social and personal insecurity today,” reports the Sierra Club. “Nearly two-thirds of the U.S. population does not have close-to-home access to nature, with the greatest disparities found in low-income neighborhoods and communities of color.”

Another way to get more of us outside is by making it easier to score a last-minute campsite. Alyssa Ravasio, founder of the start-up Hipcamp that links landowners looking for revenue streams with campers, teamed up with activists and outdoor gear makers in 2015 to launch the non-profit Access Land. The group lobbies for opening up real-time campground availability information so more of us can camp on our public lands without reserving six months in advance or winging it and risking that no sites are available after driving for hours into relatively remote areas. Upwards of 50 organizations (Sierra Club, the American Alpine Institute, Outdoor Afro) and companies (REI, Mountainsmith, Huckberry) have signed on in support of Access Land’s push for “open data” on campground openings.

“Open Data is important,” reports Access Land. “It's the reason we can access weather data on our phones, see bus timetables in Google Maps and search flights from all airlines in one place.” The group wants America’s public parks to be equally as accessible—and earlier this year celebrated when the federal government and the state of California committed to requiring open standards on their contracts with campground reservation vendors moving forward. On the heels of this success, Access Land is now stepping up efforts to convince statewide land management agencies in the nation’s other 49 states to follow suit and make their campground availability freely accessible to the public as well.

CONTACTS: Children & Nature Network, childrenandnature.org; American Public Health Association, apha.org; Access Land, accessland.org; Nearby Nature, content.sierraclub.org/ourwildamerica/nearby-nature; Hipcamp, hipcamp.com;

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