What are natural defences?

Three lines of defence

The body has different ways of defending itself against germs and bad bacteria. The most obvious defence barrier is what you can see – your skin. It is an important part of your body's defence mechanism and acts as a primary boundary between germs and your body.

However our body possesses other less visible defence mechanisms. One of the most important is your gut. Often underestimated, your gut has different roles to play:

Digestion of food: the gut is a filter that absorbs nutrients your body needs to survive.
Defence: most people don't realize it but your gut is also home to 70% of your immune system. It helps defend your body against germs that can enter with the food you eat and the air you breathe.

The gut is a true barrier between the outside world and our body. This barrier extends more than seven meters, with a surface area comparable to that of a tennis court (some 200 square meters!), and can therefore be more exposed to the external environment than your own skin!

Your gut's defence system is composed of three lines of defence that work simultaneously: the good bacteria, the gut wall and the immune system.

1st line of defence - Good bacteria: There are lots of different types of bacteria, including good bacteria in the gut. They help form a type of dense layer that acts as a first barrier, making it more difficult for germs to colonise. Normally, these bacteria are able to crowd out the germs, preventing them from multiplying.

However, the challenges of a hectic lifestyle, cold and changeable weather and other factors such as ageing (which can reduce the number of good bacteria), can all contribute to make it easier for germs to establish themselves.
2nd line of defence - The gut wall, a physical barrier: After the first layer of good bacteria, we have another barrier made of cells which line the gut. These cells form a physical barrier that helps to stop germs from getting through.

However, the challenges of every day life and the germs themselves can weaken these cells. This may make the barrier more permeable, making it easier for germs to try to pass through.
3rd line of defence - The immune system: Behind the gut wall we find the immune system, which acts as the third line of defence. In fact, around 70% of the immune system is located in the gut, helping to defend you against germs.

The effects of the immune system are, however, not restricted to the gut as immune cells, which make up the immune system, can spread all around the body to go where they are needed.

Science has shown that various factors such as stress and the process of ageing can weaken your immune system.