Burning tongue. Watery eyes. Runny nose. The sweats. These are the first few sensations that I think of, and experience, when dealing with truly spicy foods. As we grow as a culture in the understanding of how our diet effects how we live and how we feel, it is important to examine the positive effects of something as unassuming as the chili pepper.
When speaking of spicy foods, and the sense of heat we feel when ingesting them, we are referring more specifically to the active compound known as capsaicin. This compound is found, in widely varying degrees, in chili peppers. There are two widely accepted systems for measuring and expressing these levels of piquancy. The first was devised in 1912 by the American chemist Wilbur Scoville, who devised the Scoville Organoleptic Test for rating the pungency of chili peppers; the resulting numbers were placed on his Scoville scale. Scoville diluted a solution of the pepper extract in increasing amounts of sugar water until the “heat” was no longer discerned by a panel of tasters. The amount of sugar water needed to dilute the pepper solution enough to render it unidentifiable to all tasters would determine its place on the Scoville scale. Thus, a sweet, or bell pepper has a Scoville rating of zero, as the “heat” was undetectable to all of the tasters, even undiluted. On the other end of the scale, we have peppers such as the Naga Jolokia (a chili pepper native to India, where its various nomenclatures translate into such appetizing pet names as “ghost”, “cobra snake”, and “poison chili”), which rate most recently at 1,041,427 on the Scoville scale when tested by an Indian export company in 2004.
To provide some relative numbers, standard US Grade pepper spray begins at the 2,000,000 mark, whereas pure capsaicin reaches upwards of 16,000,000. The main drawback of the Scoville scale is in its imprecision, for it basically depends on human subjectivity.
For this reason, a second system was created and has become the preference when speaking of the measurement of piquancy; known as high-performance liquid chromatography. This method, also known as the Gillett Method, is much more scientific, as it employs machinery and mathematical formulas to measure the heat-producing chemicals of a chili pepper. The resulting levels are expressed in ASTA pungency units, which when multiplied by 15, produce that pepper's relative placement on the Scoville scale.
In essence, when we eat a pepper containing capsaicin, we are eating that plant's deterrent against being eaten; hence the irritating sensations it produces when we eat or even touch it. Pretty ironic that the reason we eat something is for its natural defenses against being eaten in the first place.
Psychologist Paul Rozin sites this phenomenon as an example of “constrained risk,” something that makes our body respond with warning signals, which we ignore and enjoy, much like riding a roller coaster. It is asserted by many that prolonged stimulation from capsaicin releases B-endorphins from the brain to impede and reduce pain. It is based on this idea that capsaicin has been used as a medication to aid in the alleviation of many chronic disorders, such as rheumatoid arthritis, and viral and diabetic nerve damage. However, much like a chili-eater's tolerance increases with the frequency of his or her use, extended use of this chemical leads to desensitization, and therefore a higher dose is needed to be effective.
The value of such foods as chili peppers and the reaction that they induce within our bodies have been known to cultures for over 400 years, but to science for just a few. Humans, the adaptive organisms that we are, continue to look to the ground for the solutions to the questions our world poses to us.