Red hot chili peppers

Red hot chili peppers
I'll always remember my first (and to date, last) experience with Kung Pao
chicken.
It was in a little Szechwan place at Spadina and College in good ol' T.O. I
spotted the spicy dish on the menu and remembered the name from an episode
of Seinfeld. Remember "George likes his chicken spicy"
Now, I'm no chili neophyte. I like my vindaloo, my jerk chicken, my #13 at The
Wok Inn. I really thought I could handle this.
Receiving my order, I scooped up a forkful of what I thought were black beans
or slices of mushroom and carefully chewed them into a fine paste, making sure
every past of my mouth could enjoy the delicious morsel. However, to my
surprise, horror, and eventually agony, I discovered that those were not bot
beans or mushrooms I had just consumed, but Magma-Hot Chinese Black
Peppers of Death (probably hot the accepted nomenclature, but it fits).
When the pain finally ebbed and I was able to think again (this was the
following Monday), I considered three questions: why do plants produce a
substance this pungent and painful, why do we humans react to it so violently,
and why in the name of Kung Pao himself would we put this stuff in our food
The substance in question is capsaicin, a chemical that occurs naturally in
chilies, giving them their kick. The higher the concentration of capsaicin, the
hotter the chili -- from the mildest sweet bell to the hottest habanero. In its
pure form, capsaicin is remarkably potent stuff: a dilute solution of one part
capsaicin in 100,000 parts water is still strong enough to cause blistering on the
tongue.
So why do chilies produce capsaicin Ironically, so that animals won't eat them.
As with many of the plant-derived compounds we find tasty, useful, or
intoxicating, capsaicin is a plant defence mechanism. A small mammal foraging
for food that chooses a chili will remember that burning sensation in its mouth
and avoid them in the future.
Scientists are beginning to understand why our brains perceive the presence of
capsaicin as pain and heat. In the membranes of certain nerve cells, there is a
protein which binds capsaicin, which was first cloned a year ago by scientists at
the University of California at San Francisco. Because the capsaicin molecule
contains a vanillyl group, they called the protein vanilloid receptor subtype 1, or
simply VR1.
VR1 is a channel that, when activated, allows positively charged ions, especially
calcium ions, to flow through the cell membrane. The presence of calcium ions
within the nerve cells opens more channels in the membrane and allows more

calcium in, which, in turn opens still more channels. This positive feedback is
the basis of the nerve impulse.
So, when capsaicin is around, nerves fire. But, why does it feel hot
I recently spoke to Gerald Morris, Queen's professor and head of the
department of biology. He explained that there is still more to learn about the
relationship between capsaicin and the VR1 receptor. To explain, he drew an
analogy between capsaicin and another group of compounds which have a
remarkable effect on humans: drugs derived from opium, such as morphine and
heroin, collectively called the opioids. "The obvious comparison is the opioids
and the opioid receptors, where there are the drugs opium and its related
compounds. When people looked in humans they found the endorphins."
Endorphins are part of our natural pain suppression mechanism and are
chemically similar to opium derivatives. Endorphins are the natural trigger, the
endogenous ligand, for the opioid receptor, but opioid drugs will work too.
But as Morris pointed out to me, "there is no known endogenous ligand for the
capsaicin receptor." So, it seems that we react to a completely non-toxic
compound, produced by certain plants -- with nothing chemically similar in our
own bodies -- as if our gums are on fire. Something doesn't quite add up.
"One idea," explained Morris, "is that this receptor is not only activated by
capsaicin, it's [also] activated by heat." Indeed, the UCSF study showed that
VR1 is sensitive to rapid increases in temperature, as well as to capsaicin. That
would explain why spicy foods taste "hot" -- both capsaicin and heat trigger the
same receptor.
Incidentally, capsaicin doesn't just affect the tongue and lips. Any part of the
body that has nerve endings is sensitive, including the entire skin surface, the
length of the gut, and the eyes. Morris tells a story confirming that there are
capsaicin receptors in our most delicate tissues. I won't recount the story here;
let's just say that, for graduate students working with capsaicin, it is much more
important to wash their hands before using the washroom than after.
All of this still doesn't explain why we subject ourselves to suicide wings and
prairie fires. There has been some suggestion that capsaicin and other spices
have some preservative properties, which would explain why so much of the
spicy fare originates in tropical countries where, until recently, no method of
refrigeration was available. Morris, however, favours the explanation that we
use spices because they enhance flavours. And it's not just humans who think
so.
"The was an animal study," Morris said, "where they gave rats plain food and...
food which had quite a high dose of capsaicin in it. After a period [of a week],
the rats were then given a choice. the ones that had had the spicy food --
which was enough to cause them discomfort initially -- preferred it."

Certainly, capsaicin adds another dimension to an eating experience. Being
odourless and tasteless, it stimulates parts of our mouths, and our brains, that
blander food don't.
Of course, no article on spicy food would be complete without the antidotes.
What do you do if you've had too many Guatemalan Insanity Peppers
You've probably heard that water will do more harm than good, and other than
the cooling sensation of the water, it's true. Capsaicin isn't very soluble in
water, so the best it can do is spread the heat around. Each spicy-food culture
has its own remedy. The Thais suggest sugar and the Chinese prescribe rice.
Carbohydrates do seem to absorb capsaicin or mask its effects. Indian
restaurants offer a selection of yogurt-based drink and condiments to cool you
down, and chili con carne and beer go very well together. Capsaicin is very
soluble in both fats and alcohol.
Theoretically, then, the best remedy for too many chilies would be a very rich,
very strong white Russian, made with whole milk or heavy cream.
I'll have to try that next time I dare to take on Kung Pao.
John Bowman's mom doesn't like how all of his science articles end up
mentioning booze.