Chilli is a poison. The stuff you put in your fajitas is the same stuff the police squirt in your face with a can of ‘pepper spray’. The amount of chilli contained in food is unlikely to cause you any harm, but it explains why you feel uncomfortable when you eat too much of it.
The active ingredient in chillies – the thing that ‘burns’ – is the chemical capsaicin. Interestingly, the chemical binds to a taste receptor on the tongue (called VR1), which is the same receptor that is stimulated when the food is very hot. Hence, the brain is tricked into thinking that spicy food is ‘hot’.
It has been thought that you can build up a tolerance to eating spicy food. However, all the evidence shows that this isn’t the case: repeated exposure to spicy foods makes no measurable effect on a person’s perception of its spiciness.
Others have speculated whether it is something in our genes or culture that allows some people to tolerate insanely spicy food. Sadly, this appears not to be the case either. A comparison of American and Mexican eaters showed that there was barely any difference in the amount of chilli they could tolerate.
The reason why some people enjoy spicy food more than others may be something psychological. Ingesting capsaicin triggers the sensation of pain. Perhaps curry-lovers enjoy this sensation, in the same way we love roller-coasters and horror movies – it feels dangerous, but isn’t.
One thing I can’t explain is why my cat likes spicy food. Perhaps I should try putting her on a roller coaster.
Question from Ashley Smuckers Cheng via Facebook
Answered by Dr Stu