Chillies come in many shapes, colours, sizes and strengths, but one thing they have in common is the burning sensation they cause in your mouth, eyes and any other part of your body into which their juices come into contact.

The hottest part of a chill isn’t its seeds, in fact it is the white spongy layer you find inside, called the placenta. Bite into this and you will really feel the burn.

• That burning sensation is mainly caused by a chemical called capsaicin, which is found in tiny glands in the chilli’s placenta.
• When you eat a chilli, the capsaicin is released into your saliva and then binds on to TRPV1 receptors in your mouth and tongue.
• The receptors are actually there to detect the sensation of scalding heat.

Capsaicin makes your mouth feel as if it is on fire because the capsaicin molecule happens to fit the receptors perfectly.

When this happens it triggers these receptors, which send a signal to your brain, fooling it into thinking that your mouth is literally burning.

The Chili DOES NOT WANT TO BE EATEN

• The reason wild chilli plants first started to produce capsaicin was to  protect themselves from being eaten by mammals like you.
• From an evolutionary perspective the plant would much rather have its seeds dispersed by birds.
• Oddly enough birds, unlike mammals like you, don’t have TRPV1 receptors, so they do not experience any burn.

Humans messed things up

• Producing capsaicin was the ideal way to deter mammals from eating the plant while encouraging birds to do so.
• Along came an ape with a giant frontal cortex who somehow learnt to love the burn.

Your body responds to a burst of severe pain by releasing adrenaline:

• Eyes water
• Pulse shoots up.
• Heart beats faster
• Pupils dilate.

If you can tolerate biting into some really hot chillies, it’s possible to have a “chili endorphin high” – Endorphins are natural opiates, painkillers which are sometimes released in response to the chilli’s sting. Like opiates they are said to induce a pervasive sense of happiness.

It is a form of thrill-seeking – feeding our brains’ desire for stimulation.

Beyond pain are there any health benefits to eating chillies?

In a recent study, researchers from the University of Vermont looked at data from more than 16,000 Americans who had filled in food questionnaires over an average of 18.9 years.

During that time nearly 5,000 of them had died. What they found was that was that those who ate a lot of red hot chillies were 13% less likely to die during that period than those who did not.

Researchers speculate that it could be that capsaicin is helping increase blood flow, or even altering the mix of your gut bacteria in a helpful direction.

http://www.bbc.com/news/health-39217603