Good Bacteria for the Human Body: Types & Sources Video

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  • 0:04 Bacteria
  • 0:30 Inside the Body
  • 1:46 Outside the Body
  • 2:58 Lesson Summary
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Lesson Transcript
Instructor: Lauren Posey

Lauren has taught intermediate reading in an English Language Institute, and she has her Master's degree in Linguistics.

Bacteria are everywhere, and while we often think of them as harmful, this is not always true. In this lesson, you'll learn about some types that are actually beneficial to the human body.


When you think of the word 'bacteria,' what comes to mind? You might think of harmful germs that carry disease and infection. And while it's true that some bacteria can make you very sick, not all bacteria are bad.

There are millions of microscopic bacteria, single-celled organisms too small to see with the naked eye, that live inside the human body. These tiny organisms help us with actions we do every day, like digesting food.

Inside the Body

Some types of bacteria occur naturally inside the body. This means that, if our organs are working normally, we don't have to eat any particular food or take a diet supplement in order to have these helpful organisms.


Bifidobacteria are one type of bacteria that occur naturally in the body. They live in the intestines and help break down the food you eat, which allows your body to use the nutrients for energy. One side effect of their work is that they release gas. So just remember the next time you feel gassy, that just means the bacteria in your intestine are doing their job!

Bifidobacteria help keep your gut healthy and working properly, and prevent issues like constipation and diarrhea. For the most part, they grow naturally in the gut. However, if necessary, they can be taken in the form of a supplement.

Escherichia coli

Another useful bacteria is Escherichia coli, or E. coli. E. coli often gets a bad name because there are strains of it that can make people sick if they eat it. However, there are many different strains, and some of them grow naturally in the human intestine. These are beneficial, not harmful.

E. coli helps with food digestion by using up nutrients that some harmful bacteria need to live. These helpful bacteria also take up space in our gut, making it impossible for harmful bacteria to establish themselves and grow.

Outside the Body

There are also types of bacteria that do not occur naturally in the body, at least not in any great quantity. A useful bacteria found outside the body is Lactobacillus acidophilus, which is often referred to simply as lactic acid. This is one of the bacteria that ferments milk into cheese, sour cream, and yogurt. While going through the fermenting process, the lactic acid is essentially pre-digesting the food, making it easier for us to digest after we eat it.

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