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

by Giulia Enders

They should be given the cold shoulder by washing with very hot water and soap

Rule number one: Always use plastic chopping boards because they are easier to clean properly and provide fewer grooves and ridges for bacteria to hide in. Rule number two: Always wash anything that comes into contact with raw meat or eggshells thoroughly with hot water—chopping boards, hands, cutlery, kitchen sponges, and colanders, for example.

always store them at a temperature of less than 50 degrees Fahrenheit (10 degrees Celsius).

The bacterium Helicobacter pylori lives in the stomachs of at least half of humankind.

Until that time, it was believed that bacteria could only infect wounds, and cause fevers and colds.

H. pylori bacteria have been living inside human beings for more than fifty thousand years,

One out of four North Americans is a carrier for H. pylori. Not everyone who carries it in their stomach is doomed to develop stomach problems, but most people who do have stomach problems have H. pylori to thank for their woes.

BY INFILTRATING OUR stomach’s mucus membrane and swimming around in it, H. pylori weakens this protective barrier. As a result, the aggressive acids in our stomach digest not only our food, but a little bit of our own stomach, as well. If the bacteria also possess the injection-syringe or cell-damaging gene, our stomach cells have little hope. About one-fifth of people who harbor this bacterium develop tiny lesions in their stomach wall.

Two-thirds of stomach ulcers and almost all ulcers in the small intestine are caused by an H. pylori infection.

A chronic inflammation means the cells are permanently irritated until they finally give up the ghost and break down. In older people, this can also be a cause of appetite loss. The stomach has a battery of stem cells, which constantly replace lost cells. If these replacement manufacturers are overworked, they may begin to make mistakes. Cancer cells are the result.

The probability of developing stomach cancer without the presence of H. pylori is about forty times less than with it.

the connection between Helicobacter pylori and Parkinson’s disease

suffered from trembling hands, facial paralysis, and motor problems. Researchers realized that the symptoms were most common in areas where people’s diets included cycad seeds. These seeds contain neurotoxins—substances that damage the nerves. H. pylori can produce an almost identical substance.

After more than twelve years of observing over ten thousand subjects, it was concluded that carriers of this type of H. pylori do have an increased risk of stomach cancer, but their risk of dying of lung cancer or a stroke was much lower. In fact, it was only half that of other subjects in the study.

H. pylori bacterium provides a reliable protection against childhood asthma.

Rates of asthma, allergies, diabetes, and neurodermatitis have risen as rates of H. pylori have fallen.

The incidence of eczema seems to be reduced by about one-third in people who harbor H. pylori. Increases in inflammatory gut disease, autoimmune problems, and chronic inflammations may also be a modern trend caused by the fact that we often unwittingly wipe out something that has protected us for millennia.

What part is played by agents that irritate the stomach’s mucus membrane, such as painkillers, cigarette smoke, alcohol, coffee, and stress? Is it a combination of all these that is responsible for stomach ulcers—because our little pets don’t like them?

stomach cancer, certain lymphomas, or Parkinson’s disease run in the family, it is also a good idea to offload H. pylori.

Cat’s guts are the home of Toxoplasma gondii.

The probability, in percent, of your having toxoplasmata yourself is about as high as your age in years. On a global scale, about one-third of humans harbor them.

They do not have any overly negative effects on healthy adult hosts. Some people have mild, flu-like symptoms, but most notice nothing. After the acute infection phase, the toxoplasmata move into tiny apartments in our tissue and enter a kind of hibernation state. They will never leave us for the rest of our lives, but they are quiet little lodgers.

However, an infection like this can have drastic consequences for pregnant women. The parasites can reach an unborn child via the mother’s bloodstream. The immune system is not yet familiar with them and is not fast enough to catch them.

Toxoplasmata are the reason your cat’s litter should be changed every day if there is a pregnant woman in the house (but not by her!), why raw food should be avoided by mothers-to-be, and why fruit and vegetables should always be washed.

Infection can only come from the little residents of a freshly infected cat’s gut.

The answer was yes. The risk of being involved in a traffic accident is higher among toxoplasma carriers, especially when the infection is in the active early stage rather than the later dormant stage.

Blood groups can indeed play an important role in parasite infections—some groups offer greater protection than others.

When we are infected with them, our immune system activates an enzyme (IDO) to protect us from these parasites. IDO breaks down a substance that the invaders like to eat, forcing them to enter the less active, dormant state. Unfortunately, this substance is also one of the ingredients needed to produce serotonin.

If the brain lacks serotonin because IDO has snatched it all away from under the parasite’s nose, our mood can be affected negatively.

The body occasionally uses this enzyme to snatch food away from its own cells. IDO is more highly activated during pregnancy, but only near the interface between mother and child. There, it snatches the food away from immune cells. That weakens them, making them react more mildly to the semi-alien presence of the baby.

Where would a parasite need to start if it wanted to switch off our natural fear of harming ourselves?

Certain fibers run directly from the eyes to the amygdala, so the mere sight of a spider can trigger an immediate reaction of fear.

If the amygdala gets damaged, a person can become fearless.

Men and women who were toxoplasma carriers had a different reaction to the smell of cat pee from those who were parasite-free. Men liked the smell considerably more, women less.

Unlike taste, hearing, or vision, smells are not checked out before they make their way to our consciousness. Strangely, we can dream all sensory experiences except smells.

One American clothing manufacturer even uses sex pheromones to attract potential customers. In Frankfurt, where I live, you can often see long lines of teenagers outside the store’s darkened and pheromone-scented entrance.

There is a well-known illness whose main symptom is false sensory perceptions: schizophrenia. For example, people suffering from schizophrenia might feel like an army of ants is crawling all over their back, although there are no such insects anywhere nearby. They hear voices and obey their commands, and they can be extremely lethargic. About half to one percent of people suffer from schizophrenia.

Most drugs used to treat it do so by deactivating a signal transmitter in the brain that is overabundant in people with schizophrenia: dopamine.

the proportion of carriers among those who suffer from schizophrenia is about twice that among those who do not.

THERE ARE SOME little white worms that like to live in our gut. Over many centuries, they have adapted their behavior to live with us. Half the world’s population has had a visit from these worms at some time or other.

also known as threadworms.

When are we least likely to go and wash our hands after scratching our behind? When we are oblivious to all this action because we are asleep or too sleepy to get up and head for the bathroom. And that is pinworm egg-laying time.

Scientists suspect that when kids have had worms, they are less likely to contract severe asthma and diabetes in later life.

Lack of a good night’s sleep can lead to concentration problems, nervousness, or irritability during the day.

Preventing deadly disease by banning pupils from spitting at school seemed like a simple and effective idea. We internalized it in our culture as a social rule. Those who did not comply were despised as a danger to everyone’s health. This attitude was passed on from parent to child, and public spitting became a social taboo.

The tradition of the weekly bath did not really take hold until the 1950s.

The higher the hygiene standards in a country, the higher that nation’s incidence of allergies and autoimmune diseases.

Thirty years ago, about one person in ten had an allergy. Today that figure is one in three.

More than 95 percent of the world’s bacteria are harmless to humans.

Disinfectants have no place in a normal household.