Hot Peppers

By Rob Mitchum | 1.22.07

Recently, the wife and I were enjoying a pre-movie drink at Chicago Cajun restaurant Heaven on Seven, when we made a fateful decision to order an appetizer. Being connoisseurs of spicy food, we decided to try an item called “Hot as a Mutha,” a breaded habanero chile pepper filled with jalapeno Chihuahua cheese and covered in peach salsa. It sounded delicious, and we weren’t perturbed by the little pepper icon meant to convey warning; after all, we were spicy-food veterans, we eat authentic Thai food like Cheerios and mainline wasabi.

Five minutes later, we were both furiously sucking on ice cubes, eyes watering, unable to speak, sharing a pain that showed no signs of abating. Chalk up another victory for peppers over the naïve and unsuspecting taste buds of Western Hemisphere humans.

Scientifically, the pain inflicted by hot peppers is actually a pretty well-studied phenomenon. The active ingredient, capsaicin, was used to find a novel protein, the vanilloid or TRPV1 receptor, which can be activated by that chemical, as well as heat and physical abrasion. Normally, this receptor is used to sense increases in temperature, so exposure to the capsaicin in hot peppers is literally like tricking your sensory system into thinking the external environment – or, say, the inside of your mouth -- just got a lot hotter.

So, it’s not too surprising that typing “hot peppers” into PubMed yields a healthy 99 results, while the more specific “capsaicin” yields 8111. Besides the expected links to papers about TRPV1 receptor structure and function, some interesting avenues pop up, such as the analgesic properties of capsaicin (it can be used to treat arthritis pain), the chemical’s ability to protect against experimentally-induced strokes in gerbils, and use of capsaicin as a growth substrate in certain strains of bacteria. There’s also one paper about something called a pepper maggot, which I’m pretty sure I don’t want to know about, lest I swear off spicy food forever.

But one article I couldn’t resist reading in full contained a title promising “A hot new twist to hair biology,” the kind of groaner pun scientists relish the chance to use. Hair biology is also a topic near and dear to my heart, given that baldness runs through basically every male branch of my family tree, producing a deep genetic dread about the future status of my own mop. This study, conducted by a team of scientists at the University of Debrecen in Hungary, sought to determine why the TRPV1 receptor isn’t by more than just sensory neurons, where they mediate the temperature responses discussed before. One particular TRPV1-expressing cell type that piqued their Hungarian curiosity was hair follicles, in part because (to paraphrase the article’s introduction) hair follicles are cheap and easy to run experiments on. Times must be tough for funding in Hungary.

Thankfully, these studies were conducted using cultured hair follicles, meaning the follicle cells were grown in a dish, rather than in human subjects; the abstract worried me that some poor volunteers were washing their hair with jalapeno-based shampoo, which would be, er, unpleasant. The researchers exposed these cell cultures to capsaicin for five days and found that the chemical reduced hair shaft elongation, increased cell death, and inhibited proliferation of the follicle cells. So, rather than being a cure for baldness, the spicy component of hot peppers is actually a promoter of baldness, a result that’s probably a lot less profitable for the researchers. They do, however, suggest a clinical application in treating “unwanted hair growth,” surely a pretty lucrative industry itself; they also suggest that antagonists to these receptors may disrupt hair loss, by blocking the action of endogenous activators of TRPV1 receptors. But long story short: don’t go rubbing hot peppers on your head.

A side visit to the Wikipedia page for capsaicin turned up the intriguing information that capsaicin is being considered as a potential deterrent for illicit use of pain medication like OxyContin, as reported by the Harvard Gazette in 2004. The idea is basically to put capsaicin into pills, so that if taken orally, there would be no effect, but if crushed in order to be snorted or injected, the substance would produce “intense pain,” the equivalent of “snorting an extract of 50 jalapeno peppers,” according to anesthesiologist Clifford Woolf. Woolf also goes on to describe the sensation: “… on a one to 10 scale, the pain is about a thousand … it feels like a mininuclear explosion in your mouth.” This dude has clearly thought a lot about negative reinforcement for drug users.

Finally, if only we’d had the Internet at Heaven on Seven, we could’ve learned that the most effective way to cool pepper burning is drinking milk; water is basically ineffective. I also learned that the habanero peppers we ate rate at least 350,000 units on the Scoville scale, the international measure of a pepper’s hotness; by comparison, your humble jalapeno rates a mere 2500-8000. Scoville ratings used to be established by the humble low-budget system of dilution and taste-testing, but nowadays pepper heat is determined via HPLC (High Performance Liquid Chromatography), the common lab procedure used to measure the concentration of any solution’s component chemicals. Our personal measure of Hot as a Mutha’s potency: it’s hair-recedingly, gerbil-stroke-preventingly, drug-abuse-discouragingly, burning, enough to cut anybody’s spicy food ego down to size.