There have been many different answers to this question since the dawn of civilization but it wasn’t until the work of Louis Pasteur that science started to see the connection between microbes and human diseases. The application of the germ theory to public health eliminated many diseases in the Western world as we began to develop wastewater treatment systems and clean water supplies as well as antibiotics and vaccination. Today, all the infectious diseases combined claim less than 1 percent of American lives.

It is hard to believe that there could possibly be a downside to this accomplishment but there is. A concept as powerful and successful as the germ theory often blinds us to other causes of disease. A competing idea during Pasteur’s time came from the physician and researcher, Jacques Antoine Bechamp. Bechamp felt that the overall condition of the “host” determined the course of a disease. He felt diseases were multifactorial, the manifestation of many variables that were unique to everyone.

How we think about disease and its cure is still locked into a single cause and a single cure and that is the downside to the germ theory dominance of Western medicine. When we think of genetic diseases we usually think about single gene disorders that are passed down from our parents or grandparents. Currently scientists estimate that there are over 10,000 genetic disorders caused by a mutation in a single gene. These diseases are also referred to as Mendelian disorders, after the father of genetics Gregor Mendel. Most of these disorders are quite rare and affect only one person in several thousands or millions and have a clear-cut pattern of inheritance. But they affect about one percent of the population.

Germ versus Host debate
Pasteur and Bechamp started a debate that is still being carried on today – the germ versus host debate. This century old ideological division has created two camps, Western (allopathic) medicine and Complementary and Alternative medicine (CAM). Even though the debate continues, we have embraced the idea that both scientists were right. While pathogenic microbes are reemerging as a major disease problem due to antibiotic resistance, the chronic diseases that now plague us in the 21st Century are multifactorial, a consequence of our genetics, environment and lifestyle.

Genetics is the fundamental science of all health and disease. All of us are born with genetic variations that can eventually lead to a disease state if they are not nurtured properly. What that means is that our lifestyle matters to our overall health – how and what we eat, drink and breathe, our sleep patterns, whether we exercise regularly, and how well we handle the many stressors in our lives. The stressors in our lives can be categorized as psychological, biochemical, environmental and structural but it is easier to just think of them as nurture while your genetic/genomic status is nature.

Nature or Nurture?
During the 20th Century, the scientific argument was which was more important, nature or nurture. It is now very apparent that they both matter so the phrase “Nurture your Nature” or “Nurture your Genome” may become the 21st Century’s new medical mantra.

The sequencing of the human genome placed genomics in the spotlight in our search for disease cures but in the past decade or so a “second genome” has been uncovered. The microbiome, all the bacteria, viruses, fungi, protozoa and other forms of microbial life that live on and in us, is being considered a “forgotten organ.”

The greatest concentration of microbes is in our gut containing as many or quite possibly more cells than we think of as “us” and that is more than 30 trillion. Approximately 500 to 1500 bacterial species, comprising more than 3 million genes in the microbiome, interact with “our” genome creating a complex ecosystem. During the past couple of decades studying microbes, researchers have come to realize that microbes constitute part of who we are biologically, not just life forms that live within us.

An area of intense research is the relationship between the gut and brain, referred to as the gut-brain axis. A troubled intestine can send signals to the brain, just as a troubled brain can send signals to the gut. Because the brain and the gastrointestinal system are intimately connected alterations in the gut microbiome may play a pathophysiological role in human brain diseases, including autism spectrum disorder, anxiety and depression. What’s becoming more and more clear is that the microbes in the gut are crucial for the brain and mental health.

During the past century, humans have changed our internal and external ecosystems more rapidly and extensively than in any comparable period in human history. This society-wide shift looks to be increasing our vulnerability to chronic disease. This imbalance  is a major area of research and along with genetic predispositions may be one of the underlying causes challenging our sick care system.

I would like to leave you with this thought –  maybe we need to start thinking of ourselves as ecosystems and the chronic diseases we are confronting is our internal and external ecosystems getting further and further out of balance.

Written by Bill Schaser, Director of Education