Barry Green of John B. Pierce Laboratory in New Haven, Conn., replies:
"The answer hinges on the fact that spicy foods excite the receptors in the skin that normally respond to heat. Those receptors are pain fibers, technically known as polymodal nociceptors. They respond to temperature extremes and to intense mechanical stimulation, such as pinching and cutting; they also respond to certain chemical influences. The central nervous system can be confused or fooled when these pain fibers are stimulated by a chemical, like that in chile peppers, which triggers an ambiguous neural response.
"So how does the brain decide whether the mouth is being pinched, cut, burned or affected by chemical? Scientists are not certain how the process works, but probably the brain makes a judgment based on the type and variety of stimuli being received. Stimulus to the nociceptors alone might indicate dangerous, extreme temperature. But capsaicin, the active ingredient in chile peppers, also stimulates the nerves that respond only to mild increases in temperature--the ones that give the sensation of moderate warmth. So capsaicin sends two messages to the brain: 'I am an intense stimulus,' and 'I am warmth.' Together these stimuli define the sensation of a burn, rather than a pinch or cut.
"The central nervous system reacts to whatever the sensory system tells it is going on. Therefore, the pattern of activity from pain and warm nerve fibers triggers both the sensations and the physical reactions of heat, including vasodilation, sweating and flushing.
"Most people think of the 'burn' of spicy food as a form of taste. In fact, the two sensory experiences are related but are very distinct. They innervate the tongue the same way, but the pain system that is triggered by capsaicin is everywhere on the body, so one can get thermal effects everywhere. Some liniments contain compounds that produce similar temperature stimuli to the nerves in the skin. Menthol acts in much the same way as capsaicin, but in this case, it stimulates the fibers that register cold temperatures, not those that respond to warmth. This is why products containing menthol have names like 'Icy Hot'--menthol stimulates both the hot (pain) and cold receptors, sending the brain a really ambiguous signal. That difference explains why there is no confusing menthol and capsaicin: one gives rise to a cool burn, the other to a hot burn.
"The sensations produced by menthol and capsaicin are accidents of human physiology--we obviously did not evolve receptors to react to these compounds. The chemicals fool pain receptors whose real purpose is to register critical events, like damage to the skin and the inflamation that often results. The tenderness around an injury is caused in part by the response of these same nerves to chemicals released in the skin. We humans are peculiar creatures--we've taken a nerve response that normally signals danger and turned it into something pleasurable."
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8 Comments
Add CommentInteresting, and although quite technical, not a sufficient explanation for my particular condition. I like hot spicy foods, but due to my condition I avoid eating them in public.
Reply | Report Abuse | Link to thisEven the smell of say buffalo wing sauce elicits a sweat reaction on the top of my skull, and down my temples. Since I have very little hair to contain it, it is most embarassing eating in public. I usually excuse myself 1/2 way thru the meal and swab myself down in the mens room. If I know I'm going to be eating spicy foods at a pub, I make sure I wear a baseball cap. But the friggin thing ends up soaked by the time dinner is over, and I still have to make a trip to the mens room to swab down my skull in cold water. But this doesn't apply to only spicey foods...My skull simply starts sweating whenever I eat anything...cept ice cream.... Just a fact of life I suppose. I could be afflicted with alot worse condition.
Is this a symptom of diabetes or any other health problem?
Reply | Report Abuse | Link to thisShould we get any tests done?
i am 24 years old and i have similar problem of sweating while i eat hot or spicy food, my friend have given me a name " melting man".
Reply | Report Abuse | Link to thisi also like to eat a little bit of more salt than usual people .
i am not diabetic but should i consult any doctor or its just normal.
I can empathize with the case histories above. Patients who have undergone a Sympathectomy (cutting of the nerve to control facial sweating) can develope the symptoms outlined. Has anyone found a safe way of addressing the reaction.
Reply | Report Abuse | Link to thisIs this facial sweating with spicy foods something common among the Irish?
Reply | Report Abuse | Link to thisEnter Your Comment Here.
Reply | Report Abuse | Link to thisWow! What prompted you to ask this question? I am half Irish and also have the sweaty face and head problem.
Reply | Report Abuse | Link to thisThe SciAm article seems to indicate that the reaction to capsaicin should be by the whole body. No explanation of why it's limited to just my head.
ofni999@hotmail.com
Reply | Report Abuse | Link to thisI 'suffer' from the sweating (mainly from my head) condition whenever I eat most foods or smell spicy hot food.
As Pual said there are worse things but socially I find it emabarassing to eat in public especially with strangers and ,culturally speaking, food i enjoy tends to often be prepared with pepper.
Any remedies out there please?