Healthy soil healthy people by Raya Stefanova

S-O-I-L Healthy Soil Microbes - Healthy People

S-O-I-L Healthy Soil Microbes = Healthy People

Raya Stefanova

Content

Human â&#x20AC;&#x201C; bacteria relationship.

Bacteria in modern life.

10.

Hygiene hypothesis.

14.

Natural immunity.

18.

Soil and human health.

Human â&#x20AC;&#x201C; bacteria relationship

Bacteria have survived and thrived in just about every place on earth: deep in the see, in the soil, in hot springs, even in radioactive waste. And, of course, in human beings. Humans and bacteria have coevolved and coexisted for as long as human race has existed. A recent study shows that the microbial cells that we harbor are 10 times more than our own cells. Because they are very small they weigh only about 1.3 kg, roughly as much as the human brain. The millions of bacteria, fungi and other microbes that inhabit our bodies are essential contributors to our good health. They break down toxins, manufacture some vitamins and essential amino acids, and form a barrier against invaders. The microbiome era started in the late 1990s, by culturing samples of the microbes from the mouth. Back then such samples were grown in petri dish in laboratories. Later DNA sequencing was added to the analysis, which is a way of seeing every living thing in the sample. Because the cost of sequencing was continuously dropping, such test became a standard practice of the microbiome research. Ever since what scientist have found about our own bodies is astonishing. There are more than 1,000 possible microbial species in the mouth, 150 behind the ear, 440 on the inside of your forearm and few thousands in the gut. In fact, microbes inhabit almost every corner of our bodies. But the real news is that the microbial community makes a significant difference in how we live and even how we think and feel. Scientists have found a link between changes of the microbiome to some of the most pressing medical problems of our time, including obesity, allergies, diabetes, bowel disorders and even autism, schizophrenia and depression. It is time to start appreciating the symbiotic relationship we have with bacteria. 4

Bacteria in modern life

The Dutch microscopist Antonie van Leeuwenhoek first observed bacteria in 1676, since then most of us know bacteria only as “germs,” invisible creatures that can invade our bodies and make us sick. We are bombarded with all kinds of antibacterial products; taking antibiotics for a seasonal cold is a routine, we even often ask for them. We have slowly isolated ourselves completely from the outside “wild” world, where all the germs live and it all happened the last century from human evolution. Antibiotic use is just one example of a common medical practice that is altering the human microbiome by reducing, removing, or changing fundamental elements. Antibiotics have been in broad use for treating infectious diseases in humans for over 70 years and are also used to stimulate meat production in livestock. As with vaccines, antibiotics have proven to be a very important medical advance, effectively eliminating many infectious diseases that have plagued human history. Today, as a result of antibiotics and vaccines, children do not die of the infectious diseases that killed them even 50 years ago. Indeed, as a result of the modernized western lifestyle, we have deleted many of the deathful diseases. But now we are witnessing a increasing of other disorders, where our immune system has become more fragile. However, urbanization accelerate the loss of exposure to natural environment, we have evolved to tolerate harmless organisms (bacteria, archaea, fungi, viruses etc.) from the natural environment in water, air and soil because these were inevitably taken into the body daily in large quantities, and some might even become incorporated into our microbiome. All modern practices have impact on the human microbiome. The “disappearing microbiota hypothesis” suppose that, as a consequence of routine customs in modern societies—such as clean water, sanitation, caesarean birth and antibacterial soaps—practiced over many generations, the normal inoculum 6

on which the newborn is dependent for microbiome and immune system development has become depleted in the mother. This hypothesis further suggests that we might be losing key members of our normal microbiome, generation after generation, because of the increasingly distressed microbiomes of mothers, resulting in loss of the normal microbiota needed to support human health. Whether this hypothesis is supported awaits rigorous scientific testing, but it does help frame the question of why we are currently seeing epidemics in autoimmune diseases that have been relatively rare throughout human history. Disturbances to our microbiome are key to understanding why these diseases are increasing; in turn, this understanding may lead to the treatment and, ultimately, prevention of such diseases.

Hygiene hypothesis

The “disappearing microbiota hypothesis” could be linked to the preceding “hygiene hypothesis” from 1989. The “hygiene hypothesis” proposes that the recent rapid rise of allergic hypersensitivity could be from less microbial exposure in early childhood. As we have developed a cleanlier lifestyle our bodies no longer need to fight germs as much as they did in the past. As a result, the immune system has shifted away from fighting infection to developing more allergic tendencies. The body’s immune system is designed to fight infection (bacterial, viral and parasites), but also recognizes foreign substances as allergens. With the advent of vaccines, however, the immune system is no longer taxed with fighting off life-threatening diseases such as polio and measles. And thanks to antibiotics, the immune system is no longer burdened to the extent it was in the past, with fighting common bacterial infections. Even our homes have changed how our immune system functions. Air tight doors and windows – designed to save energy – have created an increased concentration of indoor allergens. Today family is smaller, which lessens children’s exposure to germs and infections. Families with three or more children – a more common family dynamic 20 or 30 years ago – tend to have fewer allergies because more children mean more germs and greater exposure to bacteria and viruses. The natural immune system does not have as much to do as it did 50 years ago because we’ve increased our efforts to protect our children from dirt and germs. Allergies are on the rise because our society has changed the way we live. So, is there a way to find a balance in our super clean world? Finding a balance between healthy living and clean living may 10

common sense. While we should keep our houses clean, we need to be diligent about changing our furnace filters and keeping allergens like mold out of attics and basements.”

Natural immunity While the “hygiene hypothesis” mainly focuses on microbes in the home, in food and drinking water and on domestic animals, the natural immunity should include our living environment in general. Thereby the previous hypotheses could be an extend to a biodiversity hypothesis, with inevitable consequences for public health. Biodiversity means, by definition, “the variability among living organisms from all sources, including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems”. The processes that link human health and environmental changes are multifaceted, complex and difficult to examine experimentally, but it is clear that microorganisms have a key role. commensals inhabiting our skin and mucosae are not passive bystanders or transient passengers, but active participants in the development and maintenance of barrier function and immuno logical tolerance in humans, and it is becoming increasingly clear that human health depends on both commensal and environmental micro organisms. This microbial zoo includes bacteria, fungi, viruses and microscopic protozoans, although hardly any data are available on the roles of the latter. The loss of biodiversity and disappearance of natural habitats pose a serious threat to humankind because they impair many essential ecosystem services—one of which is the role of environmental microbiota in enhancing human health. Living in dense urban environments might therefore lead to an ‘immune adaptation syndrome’—that is, the inability of the immune system to adapt to microbe - poor environments—in a large part 14

of the population. At the population level, changes in disease prevalence are slow to become apparentâ&#x20AC;&#x201D;the allergy problem, for instance, became visible in the midÂ1800s even when people had been living in cities for a long time. At the individual level, immune disorders often start early in life, last for a long time, might cause disability and require continuous medical treatment, which creates a considerable burden for both patients and society. We have already lost a huge amount of natural environments in the industrialized and developed countries and thereby depleted their biodiversity; if biodiversity loss continues unabated, the prospects for public health might indeed be bleak. The growing burden of inflammatory diseases might also enter a vicious cycle if the response is to reduce further our exposure to natural environments. Biodiversity loss works in the same direction, as it diminishes opportunities for outdoor activities and therefore encourages a sedentary lifestyle.

Soil and human health

Over our evolution we have developed a complex relationship with soils. There are two types of direct soil exposure, the first being the continuous environmental exposure caused by airborne soil dust, and the second being the willful dietary ingestion of soil, or geophagy. Soil is the interface between lifeless cosmic rock and all terrestrial life and it is the fundamental source of life. Soil, the mixture of minerals, living microorganisms and dead plants and animals, covering the planet is the mother of all life. Over evolutionary time all forms of life originate from soil. Our immune system is the result of nearly 3 million years of natural selection for genetic variations that produce the antibodies that protect life from adverse effects of exposures to environmental agents that have the potential to threaten us. Scientists have recently found that the microorganisms found on human internal and external surfaces are also commonly found in soil. The microorganisms of human gut have their counterparts is soil. More than 80% of the species of microorganisms that have been identified in the soil have an analogue in the human gut. Through the evolution we were constantly exposed to soil, inevitably airborne dust and direct ingestion of soil have influenced the evolution of out immune system. The influence of soil exposure in determining health and disease is great. Such knowledge could be the basis for defining opportunities for us to adapt our modern lifestyle to effectively modify our environments in ways that will improve health and prevent disease.