Bacteria are everywhere. In the soil, on our skin, in our guts, our eyes, and our reproductive organs. Everywhere. In fact, our bodies carry roughly as many bacterial cells as human ones. A 2016 recount estimated about 38 trillion bacteria living alongside about 30 trillion of our own cells.(1)
In the last century, bacteria have gotten a bad rap. But many of them are essential for healthy digestion, immune function, and reproduction, among other things. So rather than waging a war on bacteria, we need to nourish our relationship with our microbiome.
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The War on Bacteria
Ever since we learned about germs, they’ve been a target to eradicate. And of course, that effort has been hugely successful and has saved countless lives. But we may have gotten rid of too many microbes: the ones that help us along with the ones that hurt us.
People in cultures without industrialized food production or industrial chemical cleaners are exposed to a much wider range of bacteria. They also have much lower rates of eczema, asthma, allergies, IBS, and other chronic diseases. (Of course, limited access to modern medicine brings its own dangers, like severe infections.)
In the clinic, I see the other side of this every day. Many of the conditions I treat, from eczema to asthma to digestive problems, are exactly the ones that have risen as our environments have become cleaner.
Too Clean? The Hygiene and “Old Friends” Hypotheses
In 1989, British epidemiologist David Strachan noticed that children from larger families were less likely to develop hay fever.(2) He suggested that more early exposure to infections, passed around by older siblings, might protect against allergies. This became known as the hygiene hypothesis.
Researchers have since refined the idea. Graham Rook’s “old friends” hypothesis argues that the real issue isn’t infections but the harmless microbes we evolved alongside.(3) These old friends once lived in our soil, water, food, and animals, and they taught our immune systems not to overreact. Modern life has removed many of them, and our immune systems may now attack things they should ignore, like pollen or our own tissues.
The Amish and the Hutterites
One of the most striking studies on this compared Amish children in Indiana with Hutterite children in South Dakota.(4) The two groups have similar genetic ancestry and similar lifestyles. The big difference is how they farm: the Amish use traditional single-family farms with horses, while the Hutterites use large, industrialized communal farms.
The Amish children had about one-fourth the rate of asthma and one-sixth the rate of allergic sensitization. Their homes had nearly seven times more bacterial byproducts in the house dust, and their innate immune systems looked very different. When researchers gave Amish house dust to mice, it protected them from developing asthma. Hutterite dust did not.
The lesson: a microbe-rich environment appears to train the immune system in a healthy direction.
The Role of Antibiotics and Hygiene
The discovery of antibiotics was a revolution in medicine, saving countless lives from bacterial infections. But overuse has had unintended consequences for our microbiomes, including antibiotic resistance and the loss of beneficial bacteria. When antibiotics are truly needed, they should be taken as prescribed; the goal is to avoid using them when they aren’t.
The same goes for hyper-sanitizing. Reducing exposure to harmful pathogens is important, but scrubbing everything with antibacterial products can also shrink our microbial diversity.
Even the FDA has weighed in. In 2016, it ruled that consumer antibacterial soaps containing triclosan, triclocarban, and 17 other ingredients could no longer be sold, because manufacturers hadn’t shown they were safe for long-term daily use or any better than plain soap and water.(5) Washing with ordinary soap and water is still one of the best ways to avoid getting sick. You don’t need to wage chemical warfare in your bathroom.
A Symbiotic Relationship
In acupuncture and Chinese medicine, we understand the need to live in harmony with our environment. Bacteria are part of that environment, both inside and outside our bodies. Now it looks like we need to live in harmony with our microbes, too.
So what can we do to cultivate a healthy relationship with our bacteria? The research is still unfolding, and there’s no strict prescription. But common sense gives us a few simple starting points.
Eat whole, fiber-rich foods. Plant-based whole foods feed your gut bacteria. These are called prebiotic foods because they help healthy bacteria grow, and different kinds of fiber may support bacteria in different parts of the digestive tract. This has even shown to help rebuild the microbiome after taking antibiotics.
Eat fermented foods. Sauerkraut, kimchi, kombucha, kefir, and sour pickles contain naturally occurring lactic acid bacteria, which add variety to your microbiome. They’re delicious, and you can make them at home. For my favorites and how to start safely, see Probiotic Foods for Your Microbiome.
Get Your Hands Dirty
Natural environments are full of diverse microbes that can colonize our skin and gut and help diversify our microbiome. Simply walking in nature helps. But it’s even better to get your hands dirty and touch the soil.
A 2020 study in Finland put this to the test.(6) Researchers replaced parts of the gravel yards at four urban daycare centers with forest floor, sod, and planter boxes where children grew vegetables. Within 28 days, the children’s skin microbes became more diverse and their immune markers shifted toward healthier regulation. Their gut bacteria came to resemble those of kids who spent time in the forest every day.
Animals help too. A Swedish study of more than one million children found that living with a dog in the first year of life was linked to about 13% lower asthma risk by school age, and living around farm animals to about 52% lower risk.(7)
A few easy ways to reconnect with your microbes:
- Garden. Even a few pots on a fire escape or windowsill gets your hands in real soil.
- Get outside. Parks, community gardens, hiking trails, and the beach all expose you to a wider mix of microbes than indoor life.
- Let kids play in the dirt. Puddles, mud, and sandboxes are good for them.
- Spend time with animals. Pets bring outside microbes into your home.
- Wash with plain soap. Save the disinfectants for where they’re actually needed.
Conclusion: From War to Partnership
The microbiome is a fascinating frontier in science and medicine. After a century of fighting bacteria, the research is pointing us toward partnership instead. By choosing a more microbe-friendly lifestyle through diet, cleaning habits, and time in nature, we can support this delicate balance and get the full benefit of our microbial allies.
If you struggle with eczema, allergies, asthma, or digestive issues, acupuncture and Chinese herbs can help restore balance. Learn more about how we treat skin conditions, respiratory health, and digestive issues, or read about acupuncture and the microbiome.
References
- Sender R, Fuchs S, Milo R. Revised estimates for the number of human and bacteria cells in the body. PLoS Biol. 2016;14(8):e1002533.
- Strachan DP. Hay fever, hygiene, and household size. BMJ. 1989;299(6710):1259-1260.
- Rook GAW, Martinelli R, Brunet LR. Innate immune responses to mycobacteria and the downregulation of atopic responses. Curr Opin Allergy Clin Immunol. 2003;3(5):337-342.
- Stein MM, Hrusch CL, Gozdz J, et al. Innate immunity and asthma risk in Amish and Hutterite farm children. N Engl J Med. 2016;375(5):411-421.
- U.S. Food and Drug Administration. Safety and effectiveness of consumer antiseptics; topical antimicrobial drug products for over-the-counter human use. Final rule. Fed Regist. 2016;81:61106-61130.
- Roslund MI, Puhakka R, Grönroos M, et al. Biodiversity intervention enhances immune regulation and health-associated commensal microbiota among daycare children. Sci Adv. 2020;6(42):eaba2578.
- Fall T, Lundholm C, Örtqvist AK, et al. Early exposure to dogs and farm animals and the risk of childhood asthma. JAMA Pediatr. 2015;169(11):e153219.
