Gut: The Inside Story of Our Body's Most Underrated Organ

by Giulia Enders

via the sympathetic nerve fibers, and is instructed to obey the brain in this exceptional period. It is kind enough to save energy on digestion, producing less mucus and reducing the blood supply.

So the process of making decisions based on gut feeling may involve the gut recalling how it felt in similar situations in the past.

Members of the strain called BALB/c are more timid and docile than those belonging to the NIH Swiss strain, which exhibit more exploratory behavior and gregariousness.

The researchers gave the mice a cocktail of antibiotics that affect only the gut, wiping out their entire gut flora.

They then fed the animals with gut bacteria typical of...

Behavior tests showed they had swapped roles—the BALB/c mice became more gregarious a...

more ...

This is particularly true of children with this condition. For them, hypnotherapy has been shown to produce a 90-percent

percent reduction in pain, compared with a 40-percent reduction produced by drugs.

After all, 95 percent of the serotonin we produce is manufactured in the cells of our gut, where it has an enormous effect on enabling the nerves to stimulate muscle movement and acts as an important signaling molecule.

This would be particularly useful in treating the sudden onset of severe depression in people whose lives are otherwise fine.

Anyone who suffers from anxiety or depression should remember that an unhappy gut can be the cause of

an unhappy mind.

his theory that human self-awareness originates in the insular cortex.

Each piece of information is like a pixel. The insula then organizes these pixels to form an overall image. This image is important because it represents a map of our feelings.

The brain can use the insula’s map to plan meaningful movement.

In order for the insula to create a reasonable image of our self, it probably also takes in perceptions of our environment and experiences from the past.

Information that is particularly important for the maintenance of a healthy equilibrium has more sway in the insula.

the insula creates a picture of our entire feeling body. We can then use our complex brain to embellish this image.

forty seconds.

Our gut’s microbiome can weigh up to 4½ pounds (2 kilos) and contains about 100 trillion bacteria. One-thirty-second of an ounce (1 gram) of feces contains more bacteria than there are people on Earth.

In other words, when something is wrong with our microbiome, something goes wrong with us.

Yet another might have a tendency to gain weight because the “chubby” bacteria in his gut feed him a bit too willingly.

When scientists still knew very little about bacteria, they classified them as plants. This explains terms like gut flora, which is not scientifically accurate, but it is appropriately descriptive.

habitat, nutrition, or level of toxicity.

microbiota (which means “li...

and micro...

The vast majority of our immune system (about 80 percent) is located in the gut.

The bacteria are confined to a fenced-off area—the mucus membrane of the gut—preventing them from getting too dangerously

close to the cells of the gut wall.

The immune system has to be extremely careful in the gut, suppressing its defensive instincts and allowing the many bacteria there to live in peace.

Our immune system not only says, “Hi,” it also says, “You’re okay,” or “I’d prefer to see you dead.”

must be able to distinguish between bacterial cells and the body’s own human cells.

Before an immune cell is allowed to enter the bloodstream, it has to complete the toughest boot camp of any cells.

what to do about foreign bodies that aren’t actually bacteria but remind the immune system of them?

Red blood cells, for example, have very bacteria-like proteins on their surface.

immune system would attack our own blood if it had not learned in boot camp that t...

would immediately remind our immune system of bacteria, and since the immune system knows that bacteria have no business being in the bloodstream, it would consider the donated blood cells an enemy and cause the cells

The majority of the microbes in our gut protect us simply by occupying spaces that would otherwise be free for harmful bacteria to colonize.

only 10 percent of our cells are human, with microbes accounting for the remaining 90 percent.

one could say they were dipped in the probiotic waters of the Styx while they were being born.

Beneficial bacteria provide bees with an insurance policy in times of food scarcity: they have no trouble digesting unfamiliar nectar from far-flung fields.

A PERSON’S ENTEROTYPE depends on the family of bacteria that dominates the microbe population of their gut. The choice is between families that bask in the glory of the names Bacteroides, Prevotella, and Ruminococcus.

enterotyping may help doctors predict a whole range of characteristics, such as the body’s response to soy, nerve resilience, or susceptibility to certain diseases.

Bacteroides know straight away which enzymes they need. They are equipped to extract energy from whatever we ingest.

Their ability to extract the maximum energy from everything and pass it on to us has led to the suspicion that they may be responsible for an increased tendency to gain weight.

Since no human cell is capable of producing this substance, the only possible explanation for this is that our bacteria are functioning as hidden vitamin H factories.

a less severe vitamin B1 deficiency can cause irritability, frequent headaches, and lack of concentration.

Predigested milk (yogurt) saves our body some work—we just have to finish off what the bacteria started.

Mindful yogurt manufacturers often use bacteria that produce more dextrorotatory (right-turning) than levorotatory (left-turning) lactic acids.