Ever had a 'gut feeling'? That's not just a metaphor: your gut contains millions of neurons, the same kind of cells found in the brain. Scientists are still trying to understand how our guts 'think', but in the main nerve complex that links the two, 90% of the traffic is made up of signals sent from the gut to the brain.
That cookie you’re eating is in for a pretty long journey: The digestive system in an adult human can be up to 30 feet long. The all-time longest gut belongs (not surprisingly) to the blue whale. Fully-grown adults have 650-odd feet of intestine.
Our bodies contain around 100 trillion bacteria, a large proportion of which are employed in the gut. The weight of these microorganisms is heavier than your brain.
Bile acids are digestive juices made by the liver, and they act just like detergents on a greasy plate. They begin the process of breaking down dietary fats so that the enzymes in your gut can digest them for absorption into the bloodstream.
Hydrogen sulphide - the rotten-egg smelling gas produced by bacterial action in your colon - is lethal at high concentrations. Don’t worry, though: even your stinkiest toots only contain 1-3 parts per million, and it would take 1000 times that to actually kill someone.