Eating-dirt

Let’s add a little dirt to our diets

Increasing evidence suggests that the alarming rise in allergic and autoimmune disorders during the past few decades is at least partly attributable to our lack of exposure to microorganisms that once covered our food and us. [A great op-ed piece by Jeff D Leach, a science and archaeology researcher and founder of the Human Food Project – do check out this fascinating website! Ed]

As nature’s blanket, the potentially pathogenic and benign microorganisms associated with the dirt that once covered every aspect of our preindustrial day guaranteed a time-honoured co-evolutionary process that established “normal” background levels and kept our bodies from overreacting to foreign bodies.

This research suggests that reintroducing some of the organisms from the mud and water of our natural world would help avoid an overreaction of an otherwise healthy immune response that results in such chronic diseases as Type 1 diabetes, inflammatory bowel disease, multiple sclerosis and a host of allergic disorders.

In a world of hand sanitizer and wet wipes (not to mention double tall skinny soy vanilla lattes), we can scarcely imagine the pre-industrial lifestyle that resulted in the daily intake of trillions of helpful organisms.

For nearly all of human history, this began with maternal transmission of beneficial microbes during passage through the birth canal — mother to child. However, the alarming increase in the rate of Caesarean section births means a potential loss of microbiota from one generation to the next.

And for most of us in the industrialised world, the microbial cleansing continues throughout life. Nature’s dirt floor has been replaced by tile; our once soiled and sooted bodies and clothes are cleaned almost daily; our muddy water is filtered and treated; our rotting and fermenting food has been chilled; and the cowshed has been neatly tucked out of sight.

While these improvements in hygiene and sanitation deserve applause, they have inadvertently given rise to a set of truly human-made diseases.

While comforting to the germ-phobic public, the too-shiny produce and triple-washed and bagged leafy greens in our local grocery aisle are hardly recognised by our immune system as food.

The immune system is essentially a sensory mechanism for recognizing microbial challenges from the environment. Just as your tongue and nose are used to sense suitability for consumption, your immune system has receptors for sampling the environment, rigorous mechanisms for dealing with friend or foe, and a memory. Your immune system even has the capacity to learn.

For all of human history, this learning was driven by our near-continuous exposure from birth and throughout life to organisms as diverse as mycobacteria from soil and food; helminth, or worm parasites, from just about everywhere you turned; and daily recognition and challenges from our very own bacteria. Our ability to regulate our allergic and inflammatory responses to these co-evolved companions is further compromised by imbalances in the gut microbiota from overzealous use of antibiotics (especially in early childhood) and modern dietary choices…..

The New York Times: Read the full article