A Current Look At The Hygiene Hypothesis

What is the Hygiene Hypothesis?

The hygiene hypothesis is the proposed idea, based on epidemiological data (particularly migration studies), that human beings need exposure to germs in order to develop healthy immune systems. This 1989 hypothesis, proposed by Strachan, suggests that a lack of early exposure to microorganisms and parasites can lead to a suppressed immune system, making these individuals more susceptible to allergic diseases. (1, 2)

This hypothesis came into existence as an attempt to examine and explain a strange, notable, generational rise in immune dysregulation. Research around the hygiene hypothesis tells us that developed countries have experienced a steady increase in atopic disease and disorders of immune dysregulation since the 1980s, as well as a higher prevalence of infectious disease. (1)

A Mechanism Behind the Hygiene Hypothesis

One example of a discussed mechanism referenced in the Hygiene Hypothesis is linked to microbial stimuli in early childhood. “Already at the end of 20th century the question emerged whether early infections in childhood may act protectively against childhood acute leukemia by eliminating expanding aberrant leukocyte clones through well-trained and established immune mechanisms.” (5)

Understanding the Root of the Hygiene Hypothesis

Some of the literature on this topic suggests that the “Hygiene Hypothesis” be renamed to something like “Microbial Exposure Hypothesis” or “Microbial Deprivation Hypothesis” (suggested by researcher Bjorksten). This is perhaps because in essence, the root focus of the hygiene hypothesis is the integrity of the microbiome. (7)

Additionally, it is said that avoiding the term ‘hygiene’ would help focus attention on figuring out the true impact of microbes on atopic diseases, without minimizing risks of discouraging good hygiene practice– suggesting that there is perhaps a balance to be found.

How Has the Hygiene Hypothesis Changed?

The initial utilization of the hygiene hypothesis for better understanding health has been confirmed and validated by a wealth of published data – in both animal models and humans. (3)

Research over the past decade provides evidence that links symbiotic & commensal microbes (intestinal microbiota) and parasites with immune development. Thus, this notion has “expanded the hygiene hypothesis into the ‘microflora’ and ‘old friends’ hypotheses, respectively.” (1)

Getting Dirty Helps Health?

The literature tells us that autoimmune disease is prevented in various experimental models by infection with different bacteria, viruses and parasites. (4) For some that are new to this perspective, this may seem counterintuitive. Many operate under the impression that incessantly washing their hands, using hand sanitizer frequently, and seeking cleanliness serves their health.

“The hygiene hypothesis suggests that the current epidemic of atopic disorders may be due to a reduction, in modern life, in exposure to microbes and their products.” (8)

The Downside of Being Too Clean

Renowned organic skincare formulator and iconoclast in the holistic health world, Nadine Artemis, is an advocate for not disrupting the skin’s microbiome by soaping up your entire body when bathing. She says, “you never want to soap your whole body. You really only want to do pits and privates. We’re literally compromising our immune system every day with these products.” (6)

Though this is not an excerpt from the science itself, Nadine is well respected in the clean beauty industry for her knowledge around wildcrafted skincare. Through her product line rife with nature’s botanicals, she has helped individuals restore their skin to health and true radiance. Too, she even makes skincare for music legend Alanis Morisette, herself.

Other Lifestyle Factors Impacting Immunity

Of course, there is more to immunity than hand washing and cleanliness of your integument (skin). Your body’s innate defenses are also impacted and maintained by your environment, nutrition, stressors, etc. Thus, in addition to benefitting from getting dirty more often, there are a few other key players that impact your immune health.

Mindful, intentional, personalized time in unobstructed sunlight is essential for vitamin D synthesis through your skin. “Vitamin D production is linked to sun exposure, and has been shown recently to have immunomodulatory effects” (2)

A few other factors which may result in altered microbial exposure are clean water and food, sanitation, antibiotics and vaccines, birthing practices, and moving from farm to urban living.

Also, when evaluating immune potential and implications of and for an individual, more science interestingly tells us (in line with the aboe mention of moving from farm to urban living), that “exposure to farming and cowsheds early in life prevents atopic diseases, especially if the mother is exposed during pregnancy” (2)

A Current Look At The Hygiene Hypothesis

What is the Hygiene Hypothesis?

A Mechanism Behind the Hygiene Hypothesis

Understanding the Root of the Hygiene Hypothesis

How Has the Hygiene Hypothesis Changed?

Getting Dirty Helps Health?

The Downside of Being Too Clean

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