0 Members and 1 Guest are viewing this topic.
The component of a chilli that makes it hot is a chemical called capsaicin. The very fine nerve fibres that signal pain and tempearture sensation in the skin, mouth, lips, eyes and genitals have a docking station, referred to as a receptor, for this chemical.When it binds, capsaicin triggers the nerve fibre to activate, allowing electrically charged ions into the nerve cell and provoking an action potential - a wave of nerve impulses that are transmitted to the brain. The more chilli that is applied to the nerve fibre the 'hotter' the sensation you experience.It's because the nerve fibres that signal the sensation are the same ones activated by high temperatures that the chilli effect is experienced as a burning sensation.So why can some people seem to tolerate more chilli than others ?Well it's probably down to a number of factors, and partly for the same reason that an addict craves increasingly large doses of a drug to achieve the same effect that they did initially. The reason for this is a decline in the number of receptors for that drug on the cells that the drug targets. This is known as receptor 'down regulation' and is part of the brains balancing act that it uses to tweak nerve cell communication.So, if you enjoy freqent and liberal lashings of chilli, it's possible that the nerve receptors decrease in number, rendering you less sensitive to the effects over time. But serious curry-heads need not worry, the damage is not permanent - a period of abstinence should restore you to full sensitivity.Another possible explanation is physical damage to the nerve fibre itself. In newborn and foetal animals, exposure to capsaicin kills sensitive nerve fibres. Perhaps in adults repeated exposure to the agent, whilst not killing the cells, instead causes nerve 'pruning', reducing the density of fibres available to respond to the chilli and hence presenting a smaller signal to the brain so curries taste less hot ?Lastly, anyone who keeps chickens might be interested to know that they can never appreciate the spiciness of a tikka jalfrezi, because chickens lack the capsaicin receptor and hence can quickly happily peck their way through a vindaloo or even a phal without discomfort. Whether they survive the ensuing food poisoning that inevitably accompanies a trip to a dodgy Indian, is another matter..."I never forget a face, but in your case I'll make an exception" - Groucho Marx