by Karen Telleen-Lawton, Noozhawk Columnist (read the original in Noozhawk by clicking here)
Bacteria living inside our bodies outnumber us 100 trillion to 1. This microbiota call us home, inhabiting every orifice but most abundant by far in the colon. The microbes communicate with our gut and immune system, helping us discriminate between legitimate food and pathogens such as salmonella.
“Gut microbiota operate the dial controlling sensitivity and responsiveness of entire immune system,” Erica and Justin Sonnenburg, Ph.D.s, write in The Good Gut.
Besides the compelling grossness factor, we care about our microbiome because of its intimate connection to our health. In the past half-century, the incidence of autoimmune diseases has risen dramatically. The National Institutes of Health estimates that the annual direct health care costs have reached about $100 billion in the United States. While environmental factors such as exposure to toxic chemicals, pollution and chronic stress are likely involved, evidence is mounting that a faulty relationship between the microbiota and the immune system is responsible for the development of these diseases.
Our immune system and resident microbes cooperate, but they are always negotiating for power.
“The immune system wants to enforce a safe distance between our human cells and our associated microbes,” the Sonnenburgs write. “Microbes want to ensure access to their habitat — our gut — and not be expelled.”
Englishman David Strachan posited the positive role of bacteria in 1989. He suggested that the rise of hay fever and atopy (skin allergy) in the industrial world actually resulted from reduced exposure to infectious agents. Findings began validating the theory. Children raised on farms, or in large families, or in families with dogs suffer fewer allergies than very clean, affluent households. Cleanliness rather than decreased infections seems to be associated with the rise in autoimmune diseases. These can range from annoying seasonal allergies and eczema to serious chronic conditions such as Crohn’s disease, ulcerative colitis and multiple schlerosis.
Attacking the microbiota with antibiotics also correlates with an increased risk of developing childhood asthma. Antibiotics before the age of 6 months is particularly damaging, with each course of antibiotics further increasing the risk of autoimmune disease later in life.
“Exposure to microbes … is critical, especially early in life,” according to The Good Gut, “for proper immune system development.”
Our division of bacteria into symbiotic and pathogenic is too simplistic. Before obliterating any bacteria that’s been associated with humans for eons, we need to consider potential damage to our immune system.
The interplay between genetics and environment in susceptibility to autoimmune disease is unknown. But we can help protect the relationship between our gut and microbiota by adjusting our health practices. As long as you don’t use poisons in your garden, hands dirtied from playing or gardening in the yard is not a reason to wash up. Handwashing still is important after visiting public places such as hospitals, shopping centers and zoos.
In parallel with reassessing handwashing is taking care of your own personal bacterial zoo. Probiotic supplements abound in grocery and health food stores. However, they are unregulated by the Food and Drug Administration, so it is impossible to know whether the package contains what the label says without considerable research.
Instead, you can ingest probiotics naturally by eating fermented food with live cultures. These include dairy products such as yogurt and kefir, fermented foods such as refrigerated pickles, kimchee and sauerkraut, ingredients such as miso and tempeh, and the fermented tea called kombucha (my new favorite!).
Keep your zoo happy and your digestive system purring by playing in the garden and eating probiotics regularly. I’m giving my son, whose immune system is compromised, a bag of clean dirt for his birthday — but please don’t spoil my dirty secret!
Karen Telleen-Lawton, Noozhawk Columnist
Karen Telleen-Lawton is an eco-writer, sharing information and insights about economics and ecology, finances and the environment. Having recently retired from financial planning and advising, she spends more time exploring the outdoors — and reading and writing about it. The opinions expressed are her own.