What makes peppers "hot" and what's the mechanism in our body that creates that sensation of spicy heat? Does it cause damage (because it sure feels like it sometimes), and why are they hot to begin with? Seems like it would be "expensive" for the plant to produce the heat and might drive some potential seed-spreaders away, like birds.

What makes peppers "hot" and what's the mechanism in our body that creates that sensation of spicy heat? Does it cause damage (because it sure feels like it sometimes), and why are they hot to begin with? Seems like it would be "expensive" for the plant to produce the heat and might drive some potential seed-spreaders away, like birds.

— John K., Ashland

Your first question is very easy. Capsaicinoids are what cause that heat sensation with mucous membranes, and they're found in capsicum peppers (though not in "bell" peppers) in varying degrees of "heat" subjectively measured on what's known as the Scoville scale of heat units. They're believed to be produced in the "septa" area where seeds attach to the wall of the peppers.

As for your last question, it's funny you mention birds specifically because it turns out the capsaicinoids don't cause them pain, but they do in mammals. Herbivores are quite effective at spreading seeds (just ask any cow — and they fertilize, too!), so why these plants appear to specialize with birds, it's hard to say. Perhaps birds leave the capsicum seeds viable.

Notice we skipped the mechanism part of your question? We don't have room to explain all the technical aspects of how it works, but suffice to say capsaicinoids have a profound effect on the nervous system, activating a pathway that produces an effect mammals find quite painful. Of course for humans, if it can be eaten and we can make it delicious, we will find a way to suffer through the pain.

If administered in significant concentrated amounts over time, capsaicinoids can overwhelm nerves and deplete them of neurotransmitters that report pain to the brain. If the nerves can't report pain, you don't feel it, right? So, in addition to making some incredible curries and other fantastic foods, this stuff has a vast potential as a medicine for chronic pain sufferers and even shows promise for the treatment of cancer. Capsaicinoids don't cause damage.

The compounds might even help stop the abuse of prescription pain killers, thanks to an idea from Harvard University researcher Clifford Woolf. How fast do you think Oxycontin would fade as an abused drug if, say, when crushed and snorted, you got the effect of inhaling 50 jalapeno peppers? You just might be watching it on YouTube in the coming years.

Google "Harvard Clifford Woolf" and you'll find lots of fascinating info on his research. And while we were nosing around the Harvard site we found work done by HU Professor David Borsook, who has found that pleasure and pain stimulate the same brain structures, which may explain why some people can't get enough of the hot sauce.

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