Little is known about its effects, but changing its levels, possibly through diet or with different gut bacteria, might help to control high blood pressure.

Nobody really knows what the appendix is for. Recently it has been speculated that this little extension of the gut may harbour special, protective bacteria.

If your body produces too little lactose, the unprocessed lactose feeds bacteria in the lower gut, causing pain, bloating, flatulence and diarrhoea (more information at allergyuk.org).