Lesson 1 Microbes and Health
The Hidden Heroes Inside Us
A human being has about 10 trillion human cells, but ____ are also other tiny creatures living in the human body.
These creatures are clusters of bacteria in different parts of the body, such as on the surface or in the deep layers of the ____ in the mouth and the nose, and in the lungs and the stomach.
But the greatest number of bacteria, about 100 trillion that weigh ____ to 2 kg, reside in the gut.
This may sound somewhat frightening, but these bacteria have a crucial and positive ____ on our health.
The first scientist who paid attention to these microbes in the gut and their importance was Ilya Mechinikov, who won the Nobel Prize ____ 1908 for his studies on the immune system.
He was living in Paris in the late ____ century when thousands of people were suffering from cholera, a disease that was sweeping the European continent.
As a scientist, Mechinikov was naturally driven to study this disease, which eventually led him to eat food containing the ____ bacteria.
Remarkably, he ____ get sick. Intrigued, he decided to increase his sample size and recruited a colleague to do the same.
The colleague didn’t get sick either. But ____ he tested on another colleague, the poor man became critically ill and almost died.
What made them react to the same disease in different ____
By studying cholera under the microscope, Mechinikov found that certain species of bacteria from the human gut supported and stimulated ____ cholera’s growth, while other species prevented it.
After further study, he realized that our gut bacteria were essential for human health, and that the right balance of microbes inside of us could help ____ disease.
Sadly, this view was not widely accepted at the time and was eventually ____ after Mechinikov died in 1916.
A decade later, antibiotics were discovered.
Antibiotics have saved countless lives by giving doctors and scientists the means to kill harmful germs that infect wounds, cause deadly diseases, ____ spread through food.
However, as time has passed, the miraculous power of ____ has caused some doctors to use them too much.
Moreover, people have come to see all germs as threats to good health, ____ as a result, they have done their best to keep their bodies clean of them.
A war has been waged on microbes, and people have spent ____ a century trying to kill them.
Unfortunately, this ____ has had harmful effects on health, resulting in a rise in allergies and immune deficiencies.
Fortunately, scientists are beginning to see the relationship between microbes and the human body in a new ____
According to recent studies, thousands of species of microbes in the gut have different functions, and good health is incredibly dependent upon the well-being of these numerous and diverse ____
By occupying our bodies first, they prevent harmful germs from growing ____
Therefore, ____ with a healthy bacterial community may remain unaffected by slightly infected food, but those with fewer or unbalanced microbes may suffer from food poisoning.
They also facilitate our immune system by distinguishing between good substances that should be allowed ____ our bodies and harmful ones that should be rejected.
Therefore, having insufficient germs or losing important ones ____ to various health problems.
Some microbes help
Some ____ help the stomach digest some vegetables and milk.
If they are absent, it is difficult ____ absorb certain vegetables and milk, which eventually leads to an unbalanced diet and poorer health.
Other bacteria help the body produce vitamins B ____ K, as well as important amino acids.
Some microbes in the gut determine whether particular drugs are toxic to ____ liver and whether or not other drugs will work to combat a heart condition.
Other microbes regulate the appetite hormone, which makes a person feel full or hungry. ____ these microbes may result in increased body fat.
One recent study found that transplanting a lean mouse’s gut bacteria into an overweight mouse’s stomach made the ____ mouse lose weight.
Similarly, doing the reverse made the lean ____ gain weight.
Some researchers who have realized the crucial role of microbes are trying to apply this knowledge ____ cure people.
Instead of using ____ they have found that introducing or increasing the necessary germs that the person lacks can cure some diseases.
For example, there ____ people who had a terrible form of diarrhea, so they had to go to the bathroom up to 20 times a day.
These people had not been helped ____ antibiotic therapy.
Researchers transplanted some of the good microbes from a ____ donor into these patients’ guts.
One ____ after they received their transplant, all their symptoms cleared up and the diarrhea vanished.
They were essentially healthy again. The bacterial community in their own guts came ____ resemble the donor’s bacterial community.
Given this knowledge,
Given this knowledge, nutritionists suggest the following ____ to keep our guts healthy.
____ of the easiest ways to do this is through our food.
Good microbes can be found in many of the foods we eat and whatever ____ gets to our mouths.
By eating foods that contain beneficial bacteria, such as yogurt, gimchi, and natto, or choosing a diet packed with good, fresh ____ such as garlic, onions, and unprocessed grains rich in fiber, we can cultivate good microbes.
Of course, it is also important to protect the germs that already ____ in our bodies by avoiding processed food.
Heavily processed foods such as frozen food, packaged snacks, and canned food not only lack beneficial bacteria but also contain ____ that damage the good microbes in our guts.
Another way to increase beneficial microbes is to spend ____ time in nature.
Places with diverse life forms, such as woods, beaches, parks, ____ even small farms and gardens, are abundant with diverse bacteria that germ-free urban environments lack.
In addition, we should use antibiotics ____ we must use them much less frequently.
Although antibiotics play a crucial ____ in keeping us healthy by eliminating dangerous germs, they cannot tell good bacteria from bad ones.
Therefore, whenever we use antibiotics, we inevitably damage beneficial bacteria as well ____ the harmful bacteria that we want to get rid of.
If we can affect microbes and they can affect our bodies, it makes little sense to ____ about the two separately.
Maybe it is time to stop thinking of microbes and ____ as different beings.
We need to start thinking of the microbes in our guts as a part of our bodies, like the blood cells and ____ neurons, and take care of them just as we take care of our skin and our teeth.