Our bodies are in constant contact with the environment including micro-organisms, such as bacteria, fungi, and viruses. Astonishingly, the human gut contains about 100 trillion microbial cells; this means that they outnumber our human cells by at least ten to one! So why is our body not constantly at war with the microbes that call us home? Crucially, our gut and our immune system have a friendly relationship and can usually recognise friend from foe. This means we repel invasion by harmful microbes but allow useful that make vitamins, break down food, and help protect us from harmful pathogens, to live with us peacefully. This peaceful co-existence has evolved over millions of years, but, it’s not perfect.
Sometimes this relationship gets disrupted, and that is what lies at the heart of major human illnesses. Lots of things can upset the balance, eating differently, fail to get rid of pathogens that make us ill or if our cells are more susceptible for genetic reasons. When this occurs, our immune system can get a bit out of control, leading to illnesses.
If we can fully understand this relationship, we can begin to crack some of the most fundamental problems in modern medicine.
Presented by University of Oxford.