LifeHakx – Be a Good Host
By Eva Wisenbeck 14/03/2021
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It is time we start changing our view of our bodies!
Both the inside and the outside of the human body is crammed with millions of colonies of microbes and these are of major importance to our general wellbeing and also our immune health.
While bacteria are the biggest players, we also host single-celled organisms known as archaea, as well as fungi, viruses and other microbes. Together these are dubbed the human microbiota. Your body’s microbiome is all the genes your microbiota contains, however colloquially the two terms are often used interchangeably.
The microbiome is defined as the collective genomes of the microbes, composed of bacteria, bacteriophage, fungi, protozoa and viruses, that live inside and on the human body. We have about 10 times as many microbial cells as human cells.
So, to study the human as a ‘supraorganism’, composed of both non-human and human cells, in 2007 the National Institutes of Health (NIH) launched the Human Microbiome Project (HMP) as a conceptual extension of the Human Genome Project.
One of the surprises of the Human Genome (DNA) Project was the discovery that the human genome contains only 20,000 - 25,000 protein-coding genes, about a fifth the number researchers had expected to find. To search for the missing pieces that could account for this discrepancy, researchers started looking toward other sources of genetic material that contribute to human function. One of these sources was the human microbiome.
The first surprise from this study, an analysis of the full gene content and composition of these microbiomes (i.e. the metagenome) predicts that there may be more than 8 million unique microbial genes associated with the microbiomes across the human body of these healthy adults. When compared to the total number of human genes, this suggests that the genetic contribution of the microbiome to the human ‘supraorganism’ may be many hundreds of times greater than the genetic contribution from the human genome.
Also, somewhat surprisingly, researchers found that opportunistic pathogens, which cause disease by taking advantage of those with weakened immune systems, were prevalent in the healthy individuals. However, no highly virulent microbes such as the NIAID Category A-C pathogens, which includes ebola (A), salmonella (B), or rabies (C), were found. Curtis Huttenhower, Ph.D., of the Harvard School of Public Health and his collaborators, likened these pathogens to genetic traits: genetic variants resulting in slightly detrimental traits are common even among those who are healthy, whereas high-risk genetic variants are very rare.
To understand more how this might work and why some are more at risk for disease than others please read the “Germ Theory vs Terrain Theory” blog.
Most of the microbes in the microbiome do not cause disease. In fact, humans rely on microbes to perform many important functions that we cannot perform ourselves. Microbes digest food to generate nutrients for host cells, synthesize vitamins, metabolise drugs, detoxify carcinogens (cancer causing compounds), stimulate renewal of cells in the gut lining and activate and support the immune system.
No one common microbe was present in all body sites or all individuals. Perhaps counterintuitively, researchers found that microbial communities were the most similar between similar body sites. For example, between two subjects, microbes on the first subject's skin were the most similar to the microbes on the second subject's skin. Interestingly, they don't discriminate between men and women. And even twins can have different microbiomes so human genetics may not play a major role in dictating microbiome composition.
Different parts of the body – the skin, gut, nose, vagina – all have different, distinct communities of microbes. While gut microbes have gained a lot of attention, microbes elsewhere are also important, in recent studies, scientists have found that bacteria commonly found on the skin might help protect against skin cancer for example.
Microbiomes also differ from person to person. “When you look at the overall active microbiomes between two healthy people, even if they are living in the same city, you see a tremendous amount of disagreement in their microbiome,” said Rob Knight at the University of California San Diego. Variability in the gut microbiome, Knight notes, helps to explain why people respond differently to the same foods. “Whether tomatoes are good or bad for you, whether rice is good for you or worse for you than ice cream and so on is explained by your microbiome.”.
Problems of our own making - declaring war on ourselves!?
Many of the disease phenomena making news headlines these days underscore the deficiencies of the current pharmaceutical model and reveal challenges that are the direct result of our take-no-prisoners assault and warfare on germs.
Our ancestors were exposed to billions of microbes in their homes and in their foods and it helped keep them healthy.
Most of our food comes from a supermarket. By inhibiting microbial growth in these foods to extend shelf life, or sterilising them for safety, most of the food is devoid of microbial diversity. By sanitizing our home and living space, which is furnished with unnatural and chemically produced materials, and eating these relatively sterile foods, our microbiome has become less diverse than our ancestor’s microbiomes were for hundreds of thousands of years. Even nowadays, populations living more traditional lifestyles have greater gut diversity than those of us in the industrialised world.
However before we all panic and go live in a forest somewhere, there are lots of things we can do to help our ‘ecosystem’. And as the wonderful Sarah Ballantyne says “It’s only effort until it’s habit”. By shopping and eating locally and seasonally, using gentler cleaning products, not being afraid of getting our hands dirty in soil, we can have a massive impact on our ‘ecosystem’.
By eating a diverse diet with as many types of plant foods as we can, remembering to eat the rainbow as each colour has different functions. And focusing on the “How not the What” so how was the vegetable/animal reared, grown, handled is much more important.
We need to feed our guests prebiotics, invite more friendly guests by eating probiotics and encourage the right postbiotics. For more details read the Pre- and Probiotic blog.
And as we discussed one of the easiest and quickest way to become A Good Host is to avoid ultra-processed foods – so anything with 5 or more ingredients on the label – put it back!
Even better buy foods with no labels as Dr Mark Hyman says.
Right now back to our warfare, dangerous superbugs are emerging, largely due to overuse of “anti-everything” drugs such as antibiotics and antifungals, and are ushering in a potential return “to a world in which infectious diseases drastically shorten lives.” Some have estimated that drug-resistant pathogens will become a bigger killer than cancer by 2050. Now that is something worth considering for sure!
Functional Medicine already utilise the makeup of a patients’ microbiomes for personalised and precision medicine as well as using phages and other microorganisms as treatments. It is a fascinating field of medicine, one which is moving very rapidly so stay curious and ask questions.
If you are curious and would like more information about The 99% here are some great resources.
NIH “The Human Microbiome Project: Extending the definition of what constitutes a human” https://www.genome.gov/27549400/the-human-microbiome-project-extending-the-definition-of-what-constitutes-a-human