Thursday, October 11, 2012


The role of microorganisms in maintaining health and preventing diseases in human beings is well known. Most diseases known to man are caused by microbes like mold, bacteria and virus and hundreds of medicines have been evolved over the last one century to deal with them. One often wonders how the ancestors of to day's population managed to keep the diseases at bay before the advent of supha drugs and antibiotics. Of course the mortality during olden days has been much more than what it is to day. Knowledge gained regarding the beneficial effects of some species of microorganisms gave rise to a whole new sector of industry that peddled pro biotics and pre biotics to amass a fortune during the last two decades, though how effective these commercially designed products are, still remains a matter of speculation. Rejection of many of the health claims by this industry in Europe by the regulatory agencies forcing them to withdraw most of the extravagant claims on the labels, shows the uncertainties associated with health foods based on microorganisms. This situation is compounded by incomplete and unproven scientific data relating to the association and interaction between microbes and human beings.

There are thousands of studies and publications highlighting the beneficial effects of many bacterial species, most studies being confined to in vitro and in animals. The Human Microbiome which is the sum of all the microbes that inhabit human body has been found to be an important factor in determining the relative health status of each individual. It was in 2007 that an earnest effort was made through the Human Microbiome Project under the aegis of the National Institute of Health at Bethesda, USA to study and map out the genetic make up of more than 10000 species of microorganisms present in different parts of human body and the knowledge already generated presents an amazing picture about the role played by these tiny creatures in maintaining optimum health in humans. More revealingly it was brought out that harmful bacteria of which people are too much concerned with, live in perfect harmony with their host and in co-existence with the beneficial organisms with no dangers posed to people who are healthy and have normal immune functions. Interestingly all the microbes that colonize human body, trillions in number, outnumber human cells 10 to 1 reflecting their inevitable role in shaping the health of mankind.  Microbiome makes up almost 1-3% of human body mass, highlighting their crucial importance.

So far more attention has been focused on gut microorganisms which play a crucial role in helping digestion of food, strengthening and fighting many dangerous pathogens every day. But the human microbiome is spread all over the body, being present in every nook and corner playing a positive role in protecting the humans from a variety of diseases. Interestingly different body sites are colonized by different communities of microbes, differing from each other substantially in terms of their biological activity. For example the microbial colony living in the forehead area carries a significantly different signature compared to the one that inhabit on the feet. Thus the microbiome that thrive on skin, nose, mouth, elbow, lower intestine etc vary enormously . Generally healthy people carry low levels of harmful bacteria and their population is controlled by friendly organisms present in overwhelming numbers. Also true is the fact that friendly organisms like L.reuteri secretes antibiotic like substances with devastating effect on many pathogens and there may be many such organisms which if present in substantial numbers can confer immunity against many pathogens. This qualitative information however does not answer the million dollar question as to how and why the small colonies of disease causing bacteria become destructive to the host. Probably the study using purified DNA samples from human beings and the microbiome and mapping out the sequences by DNA by the sequencing machines may eventually evolve reliable methodology to monitor genetic signals present only in bacteria to detect diseases instead of the time consuming culturing of suspected pathogens.

The study has already identified more than 10000 microbial species that inhabit human Eco-system and almost 81-99% of all genera of microbes are present in people of American continent. Considering that skin is the main barrier between the body and the out side world, maximum diversity was observed in the microbial make up on the skin surface. Similarly dramatic differences have been observed in the profile of gut microbes among American and people in other countries like Malawi, Venezuela etc while there were marked differences between microbes in adults and children. Development of human microbiome in different parts of the body from infancy to adulthood is determined by many factors like environment, food habits and community living. Interestingly it is a startling revelation that most of the genes that influence human metabolism are in microbiome and not in human genome. While human genome has only about 22000 genes for encoding proteins, human microbiome has about 8 million unique genes that encode different proteins.

According to the researchers, more than 200 in number working on the project, human beings will not be able to fully digest the food they eat or utilize vital food nutrients from these foods but for the bacterial colonies that inhabit the the gut region. It is already known that gut bacteria produce many vitamins and anti-inflammatory substances that prevent precipitation of many ailments. Generation of crucial medium chain fatty acids in the small intestine is suspected to be responsible for preventing many disorders in humans. It has been further observed that during illnesses lot of antibiotics are taken through the oral route and this results in considerable destruction of native beneficial organisms while killing the pathogens and once the equilibrium is disturbed, it takes quite some time for the population to grow back to the original density but the make up of the species changes markedly with its attended consequences. Sensitivity to antibiotics can vary enormously and some species are destroyed more extensively while others survive to varying extent. One of the reasons that antibiotics are not recommended often is this irreversible change in gut microorganism profile after recovering from the illness.  Post illness treatment with freeze dried and encapsulated lactic acid bacteria cannot restore completely the gut microbiome to its original state.

There are two critical questions that concern the dynamics of human microbiome. Extensive use of chemical sanitizing agents and personal hygienic products churned out by the industry  could have debilitating effect on the nature and type of microorganisms that thrive in those using them regularly and this may be one of the reasons why Americans are more vulnerable to infectious GI related disorders, having continuously depleted the colonies of friendly microbes. No wonder that unexplained fevers in kids below 3 years of age, now commonly encountered through out the world, were attributed to proliferation of more species of virus in the nasal region as well as in the blood. Similarly increased use of antibiotics by the people and consumption of antibiotic treated meat products invariably can lead to progressive emergence of virulent pathogens not amenable to known antibiotics. It is a fact that more than 80% of the antibiotics produced in the US is consumed by the meat industry and one can imagine the impact of such a skewed practice on human health there.

In a hilarious report an American commentator, despairing about the low immunity of his fellow citizens declared that American foods "can do with a little dirt" so that they are slowly immunized back to the desired extent. It is presumed that local
foods, farmers market foods, urban garden raised produce and others that do not involve extensive application of chemical inputs and not ferried from across the world are much more preferable than the current industrial foods undergoing severe cleaning and sanitizing by the handlers at different stages. Massive transport of fresh as well as frozen foods, both vulnerable to cross contamination during their long journey and subsequent storage for long periods are considered the root cause of the present day food poisoning episodes encountered so frequently. Emergence of Frankenstein bacteria with massive kill potential, not treatable by existing array of drugs is an indicator of the disaster waiting to confront human race in coming years, all avoidable if natural way of living is restored relying on natural resources without tampering.


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