We often overlook the influences microorganisms may have had in human evolution
In our on-going struggles to achieve food safety and sustain human health we overlook influences that microorganisms may have had in human evolution and their contributions to our good health and wellness today. This article explores some recent advances in this area.
Scientists believe that the earliest forms of bacteria and viruses evolved not long after the dawn of time from a watery broth of organic compounds. We can learn a lot from their demonstrated ability to overcome everything nature has thrown at them since that time. They survive by evolving and adapting to changing conditions as a single species and symbiotically with all other life forms including humans.
As humans we first encounter microorganisms at birth. From the moment of birth until our passing, we carry, ingest and expel trillions of these organisms. No one has an exact number of bacteria in and on our bodies, but one account I have read speculated that there are at least 10 for every human cell. Some of these microbes are essential for our survival and some we would rather do without.
Are we better because of them?
Anthropologists studying why humans outlive other mammalian species think that bacterial pathogens have played a huge role in extending human longevity over time. Studies done on primitive cultures suggest that the exposure to pathogens in the food and water supplies accelerated the development of or enhanced the human genes responsible for immunity to these pathogens. There may also be a cognitive benefit to this adaptation as well. Individuals possessing strong immunity in these primitive societies also exhibit higher IQs. It may have been this combination of a better immunological adaptability and higher intelligence that allowed humans not only to survive but to thrive in very hostile conditions.
Scientists are adamant that there was not one pivotal event in our evolution that propelled us to the top of the food chain. As we evolved over the ages, we expanded our diet to include meats, which are higher in protein and energy. This new diet, in turn, led to the development of larger and better brains as well as stronger bodies. However, the exposure to animal pathogens exposed humans to a whole new set of infections that continued the development of our immune system and, as some believe, our intelligence as well.
The good ones within us
The microbiology of the human body is not well understood, and probably the least understood is the microbiology of our digestive system, the largest reservoir of bacteria in our body. We know that our survival depends on certain bacteria in our guts to break down food ingredients, thus improving their digestibility. But there is more to it than simply aiding digestion. Unfortunately, discovering all that occurs isn’t easy. To date scientist have neither been able to replicate in a lab the conditions within our guts, nor have they been able to isolate and identify many of the residents. To put it bluntly, we don’t know what we don’t know.
Anyone who has experienced a foodborne illness can attest to what happens when the ecosystem within us gets out of balance due to the invasion of a pathogen. The traditional remedy for this situation is often a “scorched-earth” antibiotics therapy that eliminates both good and bad bacteria. Once removed, we hope that the good bacteria will repopulate themselves, but this doesn’t always happen. Another approach being tested by pathologists and physicians is to use what is called a “fecal transplant.” This involves treating the patient with the feces from a healthy relative to re-establish as close to the original gut ecosystem as possible in the patient. Results of these treatments to date appear to be very encouraging.
All living things, including humans, exist when a fragile balance is achieved with these small life forms. The foods we eat do more than providing protein, fat, fibre, minerals and vitamins. Our foods play a significant role in establishing and maintaining this delicate balance with life within and around us.
Dr. Ron Wasik PhD, MBA, CFS, is president of RJW Consulting Canada Ltd. Contact him at firstname.lastname@example.org