THE BLOG
11/27/2012 12:12 pm ET | Updated Jan 27, 2013

'Hygiene Hypothesis' or 'Old Friends' Theory?

Is it the "hygiene hypothesis" or the "old friends" theory that makes the most sense? From this report on recent papers from the International Scientific Forum on Home Hygiene, it seems like it's just two views from different sides of the same coin.

The hygiene hypothesis says that increased levels of hygiene/cleanliness have decreased our exposures to microbes like bacteria, parasites, fungi, etc. The old friends theory says that we have gradually lost touch with with microbes like bacteria, parasites, fungi, etc., that we evolved with. Hmm. Look similar?

This reminds me of an excellent book on this subject that describes how we view and relate to the world, Reality Illusion by Ralph Strauch, a former senior mathematician at the Rand Corporation. Ralph is one of those brilliant-minded people who helps to describe how we create our world-view based on our past experiences and present viewpoint.

It seems appropriate then that the scientists who promote hygiene would also deny that hygiene is to blame for many of the conditions and diseases that we face today, or at least to the degree that the hygiene hypothesis claims it to be. It seems especially appropriate that an industry that promotes the use of chemicals and antibiotics to wipe out all bacteria would be a sponsor for these type of papers -- Lysol. Looking at the final evidence however, the loss of exposure to these microbes and the conditions this loss creates is supported by both sides.

The scientists then go on to state that the overuse of antibiotics, are a "maybe" in this process. Antibiotics, which wipe out all the bacteria in the body within four to five days, are a "maybe"? Antibiotics, which permanently alter the composition of the bacterial flora of the body, are a "maybe"? Antibiotics, which transform normal friendly microbes into inflammation-promoting and disease-causing pathogens, are a "maybe"? I'll skip all the effects that they have on our environment.

As Professor Graham in the article points out, "The rise in allergies and inflammatory diseases seems at least partly due to gradually losing contact with the range of microbes our immune systems evolved with, way back in the Stone Age." With antibiotic use, we can forget about a gradual change to the range of microbes within and without. It's an immediate effect that reaches an apex with a few days, if not hours.

The scientists in the hygiene hypothesis camp could more carefully evaluate the great body of science around the "anti-old-friends" effects of antibiotics and chemicals like triclosan and Lysol, not only on humans, but also on the environment. These effects greatly reduce the diversity of natural ecosystems internally and externally, leading to greater susceptibility to all diseases.

Yes, there will be changes to these microbial environments over time, but gradual changes allow us to adapt more effectively. Dramatic, whole-system changes like those seen with antibiotic use don't allow for gradual evolutionary adaptation and progress. They weaken the diversity of our microbial friends and reduce our ability to adapt. The greater the diversity of an ecosystem, the greater its health.

As Stephen Harrod Buhner reminds us in The Lost Language of Plants:

These care-less attitudes engendered in people by universe-as-machine epistemology have resulted in tremendous reductions in plant diversity throughout the world -- in natural systems, medicine, and agriculture. Such loss of plant complexity interrupts healthy ecologies (internal and external) and allows the emergence of disease everywhere it occurs.

In the end, I think that the viewpoint of the "old friends" camp seems too focused on what's happening externally, as opposed to internally within the body, thus the neglect on the effects of antibiotics internally. Of course, if you're Mother Earth, you may view that differently in light of the devastating effects antibiotics are having on ecosystems around the world.

Both theories seem to emphasize restoring balance to our exposures to these microbes. Hopefully, the health of all ecosystems won't be lost on whose more right or wrong.

For more by Dr. Jeffrey McCombs, click here.

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