The Microbiome and Your Home

I have been reading recently of developments in the study of the human microbiome and its interconnection with the larger environment.  It is changing my thinking about how we should be building our houses (and hospitals!). A microbiome is basically the collection of organisms that inhabit a particular environment, be that the intestine or a field of daisies. It turns out that that the interaction between different microbiomes is far more dynamic that we ever imagined. It confirms scientifically that it is an illusion that we are separate from the environment in which we live; it is part of us and we are part of it.

For the last fifty years we have seen bacteria and viruses (billions of which make up the microbiome) as the enemy, and we have been at war with them on every front – at the macro scale with millions of tons/year of glyphosphate (Roundup, for example, which is actually patented as an antibiotic not a pesticide) dumped into the environment, and at the micro scale with antibiotics pumped into livestock and humans at alarmingly increasing rates.  We have been killing life wherever we meet it. We are now learning that the chronic health issues we face today, particularly autoimmune diseases, are all collateral damage of that war. We are learning that we co-inhabit the world with these organisms and they are essential to our own life.

So what does this mean for our homes? The evidence is overwhelming that buildings that get poor fresh air ventilation of can be toxic. Legionnaire’s disease and Sick Building Syndrome are life-threatening. The energy recovery ventilation systems that we provide in all our houses address this issue; even though these houses are airtight, they have plenty of fresh air at all times. Similarly, our approach to building envelope design eliminates condensation and takes away the issue of toxic mold growth getting into the building microbiome.

But is this enough? We know plenty about what makes an unhealthy building microbiome, but so little about what makes a healthy one. Do the MIRV13 filters in our ERV’s take out too much from our fresh air, for example? One study shows that exposure to dog-associated bacteria can be protective against airway allergens. Another shows that the more diverse the microbial environment, the lower the incidence of asthma. And here is a creepy one:

“children exposed to specific types of bacteria… in common with well known allergens at high levels had a reduced risk of allergic disease”..and “mice and cockroaches were the sources of these bacteria associated with a beneficial health outcome.”

These studies come from a paper called Ten Questions Concerning the Microbiomes of Buildings, and I recommend it if you want to really get into the weeds on this.

Another study, by Zach Bush, MD, examines what glyphosphates do at the human cell level, particularly regarding the gut lining, and tracks the growth of a number of chronic diseases with the parallel growth in the use of this pesticide throughout the world. Truly frightening to learn that this chemical is in the water cycle of over 60% of the planet — you get it whether you buy organic or not.

It is a paradigm shift for me to learn just how illusory is the line between us and our environment. The study is just beginning and we have a lot to learn. Our takeaway for now is:

  • Continue to provide continuous fresh air
  • Continue to design a condensation-free building envelope
  • Provide as much vegetation as possible around the home and particularly around the air intake for the energy recovery ventilation system (this does not include a green lawn maintained by weed killers and chemical fertilizers!)
  • Don’t use anti-bacterial cleaning products in the home
  • Get outside and get dirty in the garden as much as possible for a more diverse and healthy microbiome in your own body
  • Get on the floor and love your dog!
  • We stop short of inviting in mice and cockroaches.