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Quest for
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Seen at Tomasitas, a Santa Fe, NM restaurant Photo by Harald Zoschke
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By Dave DeWitt
I admit it, I was completely wrong. But I have an excuse: I was misled by published articles. For years I have written that the sensitivity in the mouth for capsaicin was controlled by the number of taste buds, and that super-tasters, people with a higher concentration of taste buds, couldn’t take the hot stuff as well as the non-tasters, who had a genetically-linked lesser number of them in their mouths. Sometime in 2002, I received an email from a reader telling me I was wrong and that taste buds could only detect sour, sweet, bitter, salty, and umami flavors. (Umami is the flavor of monosodium glutamate, or MSG.) He wrote that capsaicin is not detected by the taste buds because it does not fall into any of those five categories. This person promised to forward links to prove me wrong, but he never did, so I forgot about it.
Illustration by Lois Lyles
But in May, 2003, the proof was, well, in the spicy pudding. Scientists Elizabeth D. Prescott and David Julius of the University of California, San Francisco, announced they had identified a lipid molecule called PIP2 that plays a crucial role in controlling the strength of the burning sensation caused by capsaicin. A lipid molecule is a fatty molecule, insoluble in water, but soluble in fat solvents and alcohol–just like capsaicin. In the mouth, there is a capsaicin receptor called TRPV1 and the lipid molecule PIP2 is bound to it. In the presence of capsaicin, the PIP2 molecule separates from the receptor, causing a painful sensation. Here’s the scientific description: "In this process, the capsaicin receptor (TRPV1) is sensitized by phosphatidylinositol-4,5-bisphosphate (PIP2) hydrolysis following phospholipase C activation." That’s quite a mouthful.
Now, what governs the degree of pain? The strength of the binding of the molecule to the receptor, say the scientists–the stronger the binding, the more powerful the pain sensation when the capsaicin causes the separation. And what determines the strength of the binding? To quote the researchers: "Thus, modification of this PIP2 regulatory domain by genetic, biochemical, or pharmacological mechanisms may have profound effects on sensitivity of primary afferent nerve fibers to chemical and thermal stimuli under normal or pathological conditions."
Now I’m no scientist, but it seems to me that they are saying that the sensitivity to capsaicin is determined by genetics–some people’s lipid molecules have a stronger bond with the capsaicin receptors than others. But by stating that biochemical and pharmacological mechanisms can also play a role, this could explain why some people become desensitized to capsaicin and can take more and more heat.
I’m certain that further study will reveal even more information regarding this process, so stay tuned. And by the way, if you are worried about capsaicin destroying your five to ten thousand taste buds, you should know that all of them are replaced every two weeks, anyway. So forget about your taste buds and concentrate on the binding of your lipid molecules!
By Dave DeWitt
I have uncovered a study that seems to support what many people believe: That "men tend to have a stronger preference than women for spicy, hot foods." This conclusion, along with "men are more likely than women to seek unusual and new foods," results from a study done in 1988 by Drs. Thomas R. Alley and W. Jeffrey Burroughs of the Department of Psychology, Clemson University, and published in the Journal of General Psychology in 1991. How this study has eluded public attention over the years is beyond me, but it popped up while I was doing word searches in a subscription database, Questia. Two questions came to mind after I found this study: how were such conclusions arrived at, and are they accurate a decade and a half later?
The "unusual food" preferences section included "hot peppers" along with other foods such as squirrel, shark, buttermilk, shellfish, and eggplant.
In the past decade and a half, fiery-foods have continued their assault on mainstream American eating habits.
The Study
After examining previous studies on the subject, the authors noted that the preference for hot and spicy foods is related to sensation-seeking individuals who like to challenge their taste buds with unusual foods. Several previous studies indicated this relationship, but none of them had taken gender differences into consideration. Determined to do so, the researchers devised a study in which they utilized volunteers from introductory psychology classes at Clemson. A total of 148 questionnaires were returned from 66 men and 80 women between the ages of 17 to 32 years. Of these subjects, 93 percent were white and the rest black. They all completed a questionnaire that included questions about their most recent meal and their preferences for various spices and condiments. The "unusual food" preferences section included "hot peppers" along with other foods such as squirrel, shark, buttermilk, shellfish, and eggplant. The hot and spicy condiments included Tabasco Sauce, horseradish sauce, black pepper, red pepper, and lemon pepper.
The Results
After the questionnaires were returned and checked, the researchers applied statistical analysis to the data, especially relating to the section where the subjects rated the foods from "I would use this item very frequently" which received a rating of 5, to "Never used," rating a 1. "As predicted," the researchers wrote, "we found a stronger mean preference in men (2.66) than in women (2.25) for spicy, hot condiments." They then examined the data for past use of hot peppers, one of the 34 unusual foods, on a 4-point scale with 1 equal to "I have never eaten this" to 4 for "Eaten it many times." For hot peppers, men had a 2.9 for past use to a 2.3 for women. When the data for preference were analyzed, a 5-point scale was used, from 1 being "I would not eat this if I were starving" to a 5 for "Eager to try this item or eat it again soon." Once again the men scored higher, 3.6 to 2.6. Their conclusion was that "Men reported a stronger tendency to select spicy, hot foods in general and hot pepper in particular." They also concluded that "It seems probable that the sex differences in food preferences seen in this study are due to experience rather than genetics."
Discussion
Call me skeptical, but the sampling in this study is so small that it seems to be statistically insignificant. I would agree to the conclusions if–and only if–the following qualifications were placed upon them: the small sample, the date of 1988, the region being the South, and the lack of ethnic diversity. I would have much greater faith in the study if it had a sampling of ten times that many people, had been conducted over a two-decade time frame in different parts of the country, and was based on greater ethnic diversity. Such a study would have cost a lot of money to conduct, I realize.
But as it stands now, all we can say for certain is that in 1988 at Clemson University, among the mostly young white students questioned, men had a greater tendency than women to try and like fiery-foods. This, in itself, has a certain significance, but I don’t think that the results can necessarily be extrapolated to the general public in the United States. In the past decade and a half, fiery-foods have continued their assault on mainstream American eating habits, and I’ll bet that more women than ever before are appreciating them, buying them, and consuming them. Billy Joe may love his superhot habanero-garlic salsa, but odds are that Mrs. Billy Joe is buying it for him at the supermarket and trying it herself.
And even if the results of the Clemson study can be extrapolated to the U.S. general public, do they mean that hot and spicy marketers should focus their attention on men, who like their foods the most? No, it means that they should woo the women, who buy most of the groceries.
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