The health of your gut has a say in just about every element of your wellbeing. Unfortunately, we've found ourselves in a slightly sticky situation. The standard western diet and lifestyle doesn't do our guts much good; neither the community of bacteria living within it or the integrity of the gut lining.
The community of bacteria that live within your gut regulate your immune response, meaning they control whether or not your immune system is activated, or not; they are in constant communication with your immune system and the gut lining is the messenger. Their responsibility is to keep your immune system in check, but when there is an imbalance in the community - meaning there are more 'bad' bacteria than 'good' - the message gets confused. The bad bacteria tell your immune system to react to things it doesn't need to, thus triggering your body's inflammatory response. Now, your body is equipped with an inflammatory response for very good reason; to help protect and heal where necessary. However when your immune system is controlled by the bad guys and mis-fires, responding to everything and everything that comes it's way, inflammation is sent to work all over the body. If your gut is in a constant state of bad health, then your immune system will constantly mis-fire, causing continuous inflammation, also known as chronic inflammation. Chronic inflammation has been shown to cause al manner of disease, so it is our duty to put it right, starting with improving the health of our guts.
By improving the integrity of your gut lining and shifting the balance of your gut bacteria to be in favour of the good guys, your gut will function as it should do. This will have a knock on effect and will mean your immune system and inflammatory response will go back to behaving as they're meant to, too.