BIG IDEAS: The Gut Biome and the Will of the Micro World

The human body is a stack of cooperating organisms, some of which may be sentient. If they have a will of their own, what rally animates us?

Long ago, I used to wash my car on Sundays while listening to NPR. So, it was one Sunday afternoon on NPR that I first heard a story about a medical procedure that an obscure doctor was performing referred to as a ‘fecal transplant.’ That revolting phrase stopped me in mid-wash. A fecal transplant is pretty much what the name implies; the fecal matter from one person is transplanted via a variety of mechanisms in to another person.

Why would this be beneficial under any circumstance? The reason is because in the intestines of a normally functioning human, there are millions of bacteria and microbes and tiny organisms that play a key part in regulating the processes that keep people alive. This collection of organisms is separate from the host human; each organism has it’s own DNA. While they are not the host, they are mandatory for normal human functioning. If a person is lacking in the proper ‘gut biome’ as this ménage has come to be called, a fecal transplant from a person with the full stack can make them well again.

Gross and weird, but true.

Think for a moment about the human digestive tract; it is a tunnel that goes from the mouth to the anus. Nutrients go in, waste products come out, and there is an entire marketplace in between. It is not wrong to state that anything in this entire tunnel is not really ‘in’ your body. The tunnel is a gateway system to your body where material is screened for value and broken in to component parts for use. The mouth begins this process with taste buds for screening and saliva for dilution and teeth for crushing, and the bladder and colon completes the process by prepping and packaging the unused material for export.

Within this tunnel are ‘venders’ who participate in the market but aren’t really in the body. Bacteria in the mouth, stomach, small and large intestines are living off the passage of products and also value adding along the way.  They address issues such as the alkalinity of the stomach, they break down nutrients in to useful component parts in the intestines, they extract water from some foods, and they partially digest materials that are then absorbed in to the blood stream. They are essential employees in the food court of our digestive system.

So, what if these creatures collectively have a sort of will? What if they have an agenda? What if they have a sort of gut biome union that negotiates with the body? What if they have a strong effect on signals the body gives to the brain?

What if, on some level, the bacteria and viruses that live in us have control?

Consider the odd case of Toxoplasma gondii. This is a virus that replicates in the intestines of cats. After creating millions of new self copies, the virus is then excreted in cat poop where nature distributes it in the normal fashion. But, to replicate further, it needs to get back in to the cat so, if a rat picks up any of this virus in its environment, the virus is able to alter the rats’ brain circuitry in such a way that the rat is attracted to cat urine. Normally, the smell of cat urine triggers the rat to flee, but the virus is able to override this obvious safety adaptation and induce the rat to commit suicide; the rat goes towards the cat, the cat eats the rat, and the virus completes its journey and replicates again.

Toxoplasma is but one of a variety of behavior modifying parasites that controls the host. Rabies is another; it reproduces in the salivary glands of the host and it can induce a striking fear of water in order to keep the host from drinking and subsequently washing away the virus. then, it angers the host, the host bites another creature and the virus is transmitted. the host often does not survive.

The human gut operates with millions of purposeful creatures inside who are performing a vital function for us, but what if they have an individual or collective will, like the manipulative Toxoplasma virus? Could they be sending behavioral signals as well as digesting? It seems safe to assume that if they are inside us they are built in to the overall human decision making function somehow. But, what would they want?

Could the gut biome create signals of craving? Could they inspire violence in certain situations? Could they initiate smiles and cooperation if certain nutrients were available? Do the drive different behaviors in men than women? Is there is sexual or reproductive function? Can they operate collectively, and launch wars or induce famines?

No one knows the answer to these questions. Many have speculated that the gut is a center of intelligence and control, but the field is far too new to have tested out any hypothesis. But, when you think of all the things that drive human adaptation; nature, nurture, weather, response to attack and stress, just to name a few, it seems likely that the ‘wisdom of crowds’ would have been granted to our fellow travelers and they’d have at least a feedback mechanism to weight in. Perhaps they have the majority say. Under certain circumstances, we may be working their will, walking the world doing their bidding.

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