Bugs and Us

gevers_cover_natureA number of years ago I went to a seminar on allergies and for the first time in my life heard the words “hygiene hypothesis”. The basic definition is that excessive cleanliness and a lack of exposure to infectious organisms when we are young causes an imbalance of the immune system due to a lack of stimulation and therefore under or over development of certain branches of the immune system. As I had previously had a lot of health issues myself and had been a well medicated and very clean child, my ears pricked up. These two simple words changed my view of not just the immune system, but of how the whole body works. Since then I have been investigating how to influence the immune system using bugs, and thankfully there is a huge body of evidence which is quickly growingg showing the influence the bugs have on our health.

Recent research has revealed that we are indeed not alone. Our bodies are covered in huge amounts of bacteria, fungi and parasites. In fact only around 10% of the cells in the body are actually human! Meaning around 90% of the cells in and on our body are bugs of some description and these guys have a huge role to play in our everyday health and wellbeing. This balance of bug to human cells has led many scientists to refer to human beings as a “superorganism”.

So this isn’t called the nerd spot for nothing but I will try and keep this as clear as possible. Obviously we have our human genes, but if 90% of our body is composed of microbes then these guys are going to express their genes also. In fact only 1-2% of the genes expressed within this human “superorganism” are of human origin, the rest are bug genes ahhhhh…. It is this combo of bug and human genes that makes up what is known as an individual’s metagenome. This metagenome has a massive impact on daily bodily functions including helping with carbohydrate breakdown, the synthesis of short chain fatty acids, removal of toxic compounds and the synthesis of certain nutrients such as vitamins.

Since Louis Pasteur proved the germ theory the scientific community has been working tirelessly to try and eradicate bugs in order to prevent or treat infections. It started mainly with life threatening infections and rightly so, however this has extended to every bug known to man. Antibiotics, antifungals, vaccinations, hand sanitisers and other disinfectants have ensured that we are actively killing bacteria, viruses, fungi and parasites left, right and centre. I am not here to offer my opinion on whether it is the best idea to use those products mentioned above, however I DO need to acknowledge the affect this will have on the microbiome.

So in 2008 the Human Microbiome Project was started to characterise the microbial communities found at several different sites around the human body, and to analyse the role of these microbiomes in human health and disease. The sites that were tested were from the hair and skin, nasal passages, oral cavities, gastrointestinal tract, and urogenital tracts. What was found was that the microbes in these areas varied greatly both within the individual and between individuals. In other words the microbial composition of the forearms and underarms were likely to be completely different.

So are these microbes living in and on us goodies or badies? Well we know that there are good and bad microbes. For example we often think of the Lactobacillus genus as being beneficial, however it’s not that simple as there are a huge amount of Lactobacillus bugs out there. In fact there are around 180 species that have been found so far. Also we always have bad microbes in the body, for example no matter how many antifungals you take you will always have some Candida albicans (the main cause of thrush) in your digestive system. Therefore it is not what sort of bugs you have, but what the balance of those bugs is like.

The normal and healthy relationship that we have with these bugs is mutually beneficial, we provide them with a home and food and they help us digest carbs, build a strong immune system and get rid of toxins. However, it is the imbalances that are linked to illness. In other words if there is an overgrowth of one microbe that has the potential to cause illness and a decrease in all other microbes usually found in that area that would generally help keep things in check then illness is likely to occur. An example of this is the H. pylori bacteria found in the stomach that can cause stomach ulcers.

Beyond specific examples, chronic infections are also now considered a major cause of disease. Chronic, low grade infections cause chronic simmering inflammation which is a primary driver of most chronic disease. In fact microbes have been identified as having a large role to play in autoimmunity, cardiovascular disease, chronic fatigue syndrome, cancer and neurological problems such as Alzheimer’s.

Although it makes sense to try and wipe it out when we hear that a specific microbe is involved in an illness it also makes sense to ask why that microbe is in high levels. We should really be asking what has thrown the bugs out of balance and how can we fix it? And the first things we should be looking at are what we eat and what’s in our environment?

Next month we’ll be covering the beneficial effects of microbes in the body, and what can throw our bugs out of balance.

Please contact me if you have a need for any references used in writing this newsletter.

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