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You have a second brain in your gut, and it can live without you - Quartz


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So then why does it even need me?

Shhhhh.

Good point but thankfully they can't hear. Or read.

Ling Lee, a microbiologist, says it makes sense to think of the nervous system that governs digestion as a brain. The “gut brain,” as Lee calls it, contains hundreds of millions of neurons—“as many nerves as in an adult cat,” she says. And also, it’s autonomous.

If you chopped it out of a body, and gave it a nutrient bath in which to survive, the enteric system, as it’s also known, “would still go chomping through things,” says Lee.

The relationship between the brain and the signal-sending gut is the basis of a whole wing of scientific study. For the next year, some of that research will be collected at London’s Science Museum.

“Flavor is an illusion that you perceive in your brain from different stimuli,” says Lee, managing to sound both like the medical microbiologist she is, and like some sort of Zen dietician.

There is also much to be learned about how we eat, and how we can control it. Babies “taste” flavours in the womb, one exhibit explains, so pregnant women who eat diverse foods are likely to have less fussy children. Another set of research finds that those who eat a lot of fat and sugar are more likely to have children prone to obesity, and even other addictions, such as alcoholism.

So if we could remove the sensation of taste, some addictions might go away?

There would certainly be less temptation to eat bad food if we couldn't taste it.

What makes us eat?

The answer lies in the relationship between the enteric system, which sends messages of need or satiety, and the brain that receives them. The exhibition featured several examples of this process in action.

One is a living, breathing person: Molly Smith. Because of a medical condition, most of her gut was removed at six months old, after which Smith received all her nutrients via a vein, or sometimes directly to the heart. Taste—pineapple, wasabi, chorizo—was an alien concept for her. Smith ate and drank nothing for almost 16 years. And, lacking an enteric system, she never felt hungry.

Finally, after a multi-organ transplant gave her a new liver, pancreas and small bowel when she was 15, Smith tentatively ate a banana. The slight 24-year-old has since become a “bottomless pit” for food, according to her mother, Ann. Even with a working digestive system, it took a long time for hunger to develop. She only started feeling it in the last six months.

Why do we assume your gut wants cake? Maybe it wants kale!

My gut doesn't make me crave kale. My gut makes me crave cake. 

There’s a reason why, once you’ve given in to the temptation of one piece of cake, you’re likely to do so again.

Researchers from Oregon gave teenagers milkshakes and then scanned their brains. In teenagers who normally ate a lot of ice cream, the milkshakes produced less activity than in those for whom the experience was rare. The conclusion: we crave high-calorie foods naturally—all mammals do, from babyhood—but in satisfying the craving we become used to the effects. Achieving that same brain-firing feeling over time requires richer foods, or more of them. 

Scientists at Imperial College, London, plan to implant a microchip into the gut that can communicate with the brain, tricking it into thinking it’s full. 

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