Immune Health, Gardening and Biodiversity

You’ve heard the word “biodiversity,” meaning the number and variety of living things existing in a specific area. The more biodiverse an ecosystem, the more resilient it is to perturbation or upset. We often think of biodiversity in terms of the animals and plants we can see; it may be even more important in the world we can’t see.

For 60 years, doctors and scientists have noticed an increase in inflammation-related diseases like asthma, allergies, Crohn’s disease and ulcerative colitis. According to the Microbiome (or Hygiene) Hypothesis, as westernized life disconnected from the earth that nourishes us and moved indoors, we weakened our immune health. Michael Pollen, the author of Omnivore’s Dilemma, is quoted as saying, “Some researchers believe that the alarming increase in autoimmune diseases in the West may owe to a disruption in the ancient relationship between our bodies and their ‘old friends’ — the microbial symbionts with whom we coevolved.”

Each of us is home to 100 TRILLION BENEFICIAL organisms living in and on us, in complex communities that are essential to our health and survival. Their combined weight is as big as our brain! They protect our skin from invasion, they synthesize and transfer amino acids, they ferment and digest fiber, signal cells to wage war against harmful viruses, on and on and on.

Several studies from the NIH Human Microbiome Project point out that loss of gut microbial diversity and changes in “community architecture” play a role in diseases such as Crohn’s Disease and inflammatory bowel diseases.  A 2012 Finnish study found that babies raised with dogs had fewer colds and ear infections than those raised in a pet-free household, especially if the dog spent time OUTSIDE (my emphasis).

In 2015, a study reported on Karelia, an area divided between Russia and Finland after World War II. The Finnish Karelia became increasingly westernized while Russian Karelians continued to live in an intact, diverse forest and had daily contact with farm animals. By the early 2000s, Finnish Karelians had much higher rates of allergies, while Russian Karelians had greater microbial biodiversity on their skin!

A comparison of Amish and Hutterite children*, found that Amish kids were much less allergic than Hutterite children even though the house dust from Amish homes had seven times more the amount of bacterial remnants than that of Hutterite homes. The Amish live on single-family farms and use animals for farming. The Hutterites practice large-scale modern agriculture, with their homes located farther from their fields. When an extract of Amish house dust was introduced into the nasal passages of germ-free mice with induced asthma symptoms, the mice exhibited reduced airway excitability and inflammation.

But, before you start creeping around in Amish houses to collect dust to enhance your immune system, consider stepping out into your own backyard or the forest. Healthy soil rich in organic matter can contain up to one BILLION bacteria per teaspoonful and hundreds of thousands of other organisms. Allow your hands to contact the soil. Go barefoot. Grow some of your own fruits and vegetables. It will increase your own biodiversity. Get your hands dirty, for the sake of your immune system!

 

*Source: Never Home Alone by Rob Dunn; “Absence as a Disease” Hachette Book Group, New York, 2018.

Rebecca Miller-Cripps is a University of California Cooperative Extension Master Gardener of Tuolumne County.

UCCE Master Gardeners of Tuolumne and Calaveras Counties can answer home gardening questions. Call 209-533-5912 or fill out our easy-to-use problem questionnaire here. Check out our website here. You can also find us on Facebook.