how “friendly” bacteria actually help your immune system?


I’ve read so many things on this subject and I’m still no nearer to understanding it!

In: 27

Bad bacteria make poison. Good bacteria either don’t make poison or make things our body likes. When good bacteria take up all the space there is no room for bad bacteria to live.

There’s all sorts of bacteria living inside and outside of us. They all do different things that can help us or just don’t bother us enough for our bodies to care and some that try to harm us.

The bacteria in your mouth help digest certain types of food molecules and whatnot.

Some bacteria in our guts help out our immune system for a free ride. A type of symbiotic relationship between our bodies cells and bacteria.

One type of bacteria activates a inflammatory response for our immune system. Another type controls how much of our immune system actually responds to an invader. That way our immune system doesn’t take us out too.

Our immune system is very complex and has many many systems that work together to protect us.

Bacteria that lives inside of us have proteins on their surface that interact with our immune cells to give off the sign that our immune cells register as friendly. Some harmful bacteria and viruses have evolved a similar types of way to attack our immune systems.

We first get our first dose of friendly bacteria through our mothers birth canal or through our mothers skin if they had a c-section. We get the rest through our everyday environment and food. Bacteria is everywhere after all.

Hope this helps you out, there’s still a lot of research that is being done on this subject still so time will tell for more information.

humans live in a relationship with the bacteria in / on our bodies. Some bacteria make people sick. The friendly bacteria, on the other hand, help you break down the food you eat so you can use the nutrients to grow and repair your body’s tissues, including the immune system. The friendly bacteria also help to fight the unfriendly kind.

you can see what happens when friendly bacteria are not there, for example, in people living with untreated HIV whose friendly bacteria have been wiped out. Or cancer patients. They can’t eat well and they can’t put on weight.

tl;Dr: you need friendly bacteria to feed your body.

1. Competition – It is more difficult for “bad” bacteria to gain a foothold when they have to compete with “good” bacteria. This is why people are more likely to get opportunistic infections like *C. diff* after taking antibiotics.
2. Crosstalk between immune cells and good bacteria that goes beyond the scope of ELI5, but for simplicity we’ll just say it’s practice for the immune cells. ([more information in this review article](
3. The gut bacteria in particular are important for producing certain vitamins and helping us absorb nutrients, deficiencies can negatively affect health and indirectly weaken the immune system.

Okay, so you know how there are good guys and bad guys in movies? Well, it’s kind of like that in your body too! The friendly bacteria are like the good guys, and they help your immune system by fighting off the bad guys (like germs) that can make you sick.