There has been a good amount of news recently about the Human Microbiome project, and whenever I read about the latest scientific breakthroughs I always try and relate it back and see how it may shed further light on the efficacy and mechanisms of Traditional Chinese Medicine. I would like to share some of my intuitions here with you on my blog. However before I begin here is a quick summary of what the human microbiome is.
A growing band of biologists see people not just as individuals, but also as ecosystems. A healthy adult human harbours some 100 trillion bacteria in his gut alone. That is ten times as many bacterial cells as he has cells descended from the sperm and egg of his parents. These bugs, moreover, are diverse. Egg and sperm provide about 23,000 different genes. The microbiome, as the body’s commensal bacteria are collectively known, is reckoned to have around 3m. Admittedly, many of those millions are variations on common themes, but equally many are not, and even the number of those that are adds something to the body’s genetic mix.And it really is a system, for evolution has aligned the interests of host and bugs. In exchange for raw materials and shelter the microbes that live in and on people feed and protect their hosts, and are thus integral to that host’s well-being. Neither wishes the other harm. In bad times, though, this alignment of interest can break down. Then, the microbiome may misbehave in ways which cause disease.
One way to think of the microbiome is as an additional human organ, albeit a rather peculiar one. It weighs as much as many organs (about a kilogram, or a bit more than two pounds). And although it is not a distinct structure in the way that a heart or a liver is distinct, an organ does not have to have form and shape to be real. (This accords well with the Chinese medicine view of organs which go beyond the form and shape of an organ - but encompass the other components that give its functionality). The immune system, for example, consists of cells scattered all around the body but it has the salient feature of an organ, namely that it is an organised system of cells. The microbiome, too, is organised. Biology recognises about 100 large groups of bacteria, known as phyla, that each have a different repertoire of biochemical capabilities. Human microbiomes are dominated by just four of these phyla: the Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. Clearly, living inside a human being is a specialised existence that is appropriate only to certain types of bug.
Stepping back we can see that the human body then begins to lose its image of being a fixed entity rigidly determined by ones genetics, but an organism that is in dynamic exchange with its environment. Each organ (especially the gut and digestive tract) has its associated bacterial flora and this changes depending on the external environment (geography, time of day, weather) as well as internal states (stress, happiness, etc.) and this potentially impacts the functioning of the organ. This accords well with the holistic view of the world the TCM takes.
The flora are specialised; but not monotonous. Just as ecosystems such as forests, grasslands and coral reefs differ from place to place, so it is with microbiomes. Those of children in Malawi and rural Venezuela, for instance, contain more riboflavin-producing bugs than do those of North Americans. They are also better at extracting nutrition from mother’s milk because they turn out lots of an enzyme known as glycoside hydrolase. This converts carbohydrates called glycans, of which milk has many, into usable sugars. In my studies of qigong one of the highest states that one reaches is one where the practitioner does not have to take in any food 避谷 (bigu), my intuition is that this could potentially be achieved with a state where the bacteria take over the production of food in the body, rather like photosynthesis and mitigates the need for the practitioner to take in any further food.
Clinical trials have indeed shown that probiotics (a mixture of bacteria found, for example, in yogurt) ease the symptoms of people with irritable-bowel syndrome, who often have slightly abnormal gut microbiomes. Whether they can cause a beneficial shift in other people is not known. However yogurts are limited in the range of bacteria they can transmit. Another intervention, though, allows entire bacterial ecosystems to be transferred from one gut to another. This is the transplanting of a small amount of faeces. I won't go into the details here, but my other intuition is that a large part of Chinese medicine, being based on herbs may allow the seeding of new benevolent culture or provide the nutrients that promote the growth of a certain form of bacteria. Thus even in a highly diluted state it could kick start the reproduction of certain forms of bacteria, like seeding a solution with a crystal. This would address many of the criticisms that the active ingredients in Chinese medicine are too dilute to have a noticeable effect on the body.
These are some of my initial intuitions when reading the following articles. Would welcome any further thoughts that my readers may have.
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