Chapter 5: Discovering why some (don’t) like it hot
– Is it a matter of taste?
This is the fifth article of the series and here I am getting to the main topic with which the book titled ‘Why some like it hot…’ attracts the readers.
Why some people like their food hot spicy while others cannot stand it (including me)?
The chapter starts with the difficulties of Columbus crew to describe the hot spicy taste of a new plant they were introduced to when they met the domestic culture. They tried to describe it as ‘sharp taste’ and made it analogous to the pepper, which the European already knew from trading with the Middle East. It is thought that this new plant was the cayenne pepper and they encountered the capsaicin – a very strong irritant. This kind of compound is called a vanilloid and is seen as a chemical paradox because it has a dual capability to cause and relieve the pain.
The author (Gary) then discussed differences in food preference, distinguishing between the free will for the food choice and the possibility of genetic and cultural predisposition to ‘favor the flavour of some foods over others’. He also expressed the complexity of relationships related to the ‘pungent peppers that Columbus brought from Americas; as being a mixture of mystery, pain and pleasure.
“… they are a sensation that literally makes or breaks certain human relationships.”
Gary mentioned his personal experience when dating a woman who was a supertaster. He cooked a lovely, albeit spicy, meal for her. He assumed that anyone could tolerate the amount of chilli as he could. The dinner turned into a disaster because she was ‘hardwired’ to sense the peppers as intense burning in the mouth. She even tasted the lime juice as bitter in her margarita drink and she did not like it. Gary managed to save the evening with some alterations to the meal for his date and he continued with the original version without any difficulties. And it was not because he would have burned out his taste buds during the years of enjoying hot spicy foods as some believe. He was simply a non-taster ‘by his genetic profile, having minimal reactions to strong flavours’. However, he admits that his taste buds might have been ‘desensitized’ over two decades in field when he sampled chillies in amounts exceeding the experience of most Americans. He called this fact as a
“perfect example of the fascinating interplay between genes, habitat, culture and individual experience”.
“Not one of these factors in isolation can account for why some like it hot, and others not.”
Scientific explanation of the effects of capsaicin
The different perception of tastes among people was named as polymorphism and in this case it was the polymorphism for the ability to taste chilli. Some people (or populations) are genetically predisposed to supertasting. They are able to notice subtle amounts of tastes, including bitterness when others notice nothing.
The scientists have been examining the connections between taste and oral pain. Some suggest that the taste system inhibits activities which are not compatible with eating, including oral pain. They say that the ‘taste input appears to inhibit oral pain in the brain’. When taste is damaged, that inhibition is abolished and pain sensations are produced in supertasters in the absence of normal stimulation for pain. These supertasters then suffer a burning mouth syndrome when hypersensitive to chilli. The scientists tested these people with a very simple method: a stripe of chemically treated paper was put on the tongues of the study participants of various ethnicities examining how well they sense bitter taste. Those who were responding with the signs of disgust were also sensitive to various bitter herbs, coffee, condiments or fruits, such as grapefruit.
The taste-blind people have been found to be carriers of a heritable trait with health implications. While supertaster infants show aversion to the cruciferous vegetables such as broccoli, the non-tasters do not sense the bitterness of these plant foods and they can eat lots of greens, which, however, can act as goitrins in large amounts, disrupting the thyroid gland function. That means their iodine metabolism can be affected. Another example is the sweet taste which the supertasters perceive much stronger than non-tasters.
Gary mentions that the supertasters can have this taste sensitivity enhanced by a factor of two. They also “feel more pain from lesions on their tongue and that is medically very important”. Other substances for identifying supertasters trait include PTC (phenylthiocrarbamide), PTU (phenylthiourea) and PROP (96-n-propylthiouracil). Similar sensitivity has been reported for alcohol. Especially the PROP-tasting genes have been linked with alcoholism running in families while supertasters do not find such pleasure in drinking. I now understand why the original Listerine mouth wash was such an ordeal for me and I have never bought it again.
On the other hand, because the non-tasters do not refuse bitter taste, they eat more of bitter greens, grapefruit and other foods, which make them less likely suffer some forms of cancer, although it was proposed that eating chilli is correlated with a higher incidence of stomach cancer.
Interestingly, the science says that supertasters are ‘super perceivers of fat in food’, too! Possibly. Research shows that elderly women who are supertasters are less likely to suffer cardiovascular diseases because they tend to weigh less, have lower fat mass and better blood lipids profile than non-tasters.
Therefore, you can see that the supertasters and non-tasters live in different “taste worlds” and have different health risks profiles.
This genetic trait for supertasting or non-tasting occurs at different rate of prevalence among various cultures and ethnicities. Up to 30% of the Mediterranean habitants were found to be taste-blind, whereas only 7 % of Lapps or 2% in Navajos. In India it was 43% and we know that Asians love spicy food as much as the Mexicans do. As Gary said:
“…heritable taste preferences have had unforeseen influences on our consumption and nutrition, and ultimately, on our health status.”
Nonetheless, there is also a middle ground. This may include me: I cannot eat hot spicy food but I quite enjoy eating cruciferous vegetables. I even manage it without adding salt or other flavourings. Plain steak is perfectly fine for me, too. But I do not like finishing a pint of beer. I find its bitter taste off-putting, but the first few sips are refreshing. Therefore, there is a range of intensities of responses, depending on the concentrations of substances. These “perceptual differences … are rooted in anatomical, physiological and genetic variation among us”.
When studying the anatomy of the tongue, the scientists have discovered that in supertasters, their tongues are “literally tiled from edge to edge with taste buds nested in dense fungiform papillae, whereas the tongues of non-tasters are sparsely polka-dotted with taste buds.” The non-tasters have been found to carry “two recessive alleles for the genes influencing taste-bud density and PROP tasting … located on chromosome 7”. Therefore the scientists assume that the supertasters carry the dominant alleles and those in between have combination of these.
Despite that, Gary suggests that people can learn to some degree their response to various tastes based on the cultural background to either perceive it as a ‘sadistic plot intended to inflict pain’ or to see the meal as ‘ providing intense pleasure’ or even sexual pleasure.
Sexual stimulation to reduce pain?
I have mentioned previously that chillies have a dual effect: being able to curb pain or intensify the pain. This was though as being conditioned by being either a supertaster or non-taster. As Gary expressed:
“chronic chillies eating might ‘swamp’ the endorphin system in the body so that chilli eaters might be less tolerant of pain.”
And because of the anticipated geographical distribution of supertaster or non-tasters, in 1989 was conducted a study on 25 Mexican women from Xalapa country (chilli eaters, definitely) by Beverly Whipple. In short: they hypothesized that vaginal self-stimulation of women should lead to pain relief. They separated them into three groups according to their relationship to the chillies: from chilli lovers to those that could not stand them and any other hot spicy food. The description of the pain threshold estimation follows in the chapter. The outcome of the study was that the accumulation of capsaicin in the bodies of non-tasters hindered the natural analgesic effect of orgasm. Eating chillies saturated the endorphin ‘engines’, making the brain ‘supersaturated. Those women, who did not like chillies and were assumed to be supertasters, had the benefit of pain suppression during the orgasm.
This differential response to pain was also observed in the A&E where mixed population attended. Although it could have been partly a culture thing when some cultures bring up their youth to manage pain better than other cultures, the genetic factor and perhaps the dietary favour for endorphin stimulants may also have played a role. Gary expressed his thoughts that we might be genetically (in addition to culturally) predisposed to express our pain or pleasure in more or less dramatic way.
Later in the chapter Gary looks for the evolutionary reason for chillies making us feeling burning sensation and why the plant has evolved like this, synthesizing so high amounts of such a potent irritant – capsaicin. Gary says:
“The piquant (spicy) peppers evolved their mechanisms of attraction and defence, encouraging some animals to eat them and disperse their seeds, while repelling those that might sample them and destroy their seeds, thereby limiting the chillies reproduction and survival.”
Interestingly, 4/5 of wild chillies with tiny peppers took advantage of protective cover under the foliage of hackberry tree, providing a shelter and fertile soil underneath. However, these bushes were not too abundant in the area of Arizona canyon where the scientist decided to the research. They found out that the wild chillies, despite being so sharp tasting, managed to have their seeds dispersed under other blackberry trees, via some birds, such as finches. The birds craved carotene for their new feathers during the autumn and the chillies packed with carotenes provided them exactly that. The birds fly to the canopy and disperse the seeds under hackberry tree. Some mammals which would have the same potential for the chillies, however, did not touch the chillies, but picked the hackberry fruits instead. As the further research confirmed, it was the birds which were not put off by the sharp taste of chillies while the mammals were. They showed aversion to the chillies and even lost weight when force-fed with them. Therefore it was only the birds that helped dispersing the seeds under the hackberry trees while the mammals would move around and trash the seeds in less fertile soils – meaning lower chances for germination and successful growth of the chillies. In addition, the mammals would destroy the seeds when forced to eat the chillies, meaning even less chance for the plant to survive as a species. That is what we call symbiosis – between the chillies and birds and part of this symbiosis was something called directed deterrence. The sharp taste of irritating capsaicin deters the mammals to pick on chillies, giving even more chances for non-tasting birds to feast on them and to disperse the seeds further. These vanilloids, similar to capsaicin, are found also in black pepper or ginger and the bodies of mammals process them similarly – responsing with increased body temperature and producing the neural sensation in form of tingling or pain.
Difference in sensation
Birds have been found to have different molecular pathway for pain. They are not put off from eating the chillies, but they react to a proper heat. This is typical for other species such as reptiles or amphibians which have low sensitivity to capsaicin and they do not sense it as burning, in contrast with us, mammals. The scientists think that mammals have developed this heat sensation after exposed to capsaicin relatively recently. So why do humans still seek this ‘inflammatory’ compound and enjoy it in their food?
According to Paul Rozin, humans firstly used the chillies as the external remedy before they decided them using internally. Then humans used small amounts of chillies to give their food a kick and when they domesticated several species of chillies, they now use it as a vegetable. Then Gary cited Paul Rozin:
“In almost every culture, at least one innately unpalatable substance becomes an important food or drink.”
But what exactly made people love these peppers, despite their pain inducing properties, remains a mystery. Perhaps the different perception of their taste from the non-tasters is the key. Other possible reasons were named in the chapter on which I have based this article. However, one very important possible factor played a significant role: chillies help to prevent early spoilage of food by reducing the growth of microbes that are naturally present on our food. Also parasites and moulds can be reduced, especially in meat based food. That was a useful property especially in temperate climate. This may have provided a ‘fitness’ of chilli eaters and some have even reported their like of the burning taste. This spice-protecting effect was proven when the scientists have looked at the typical cuisines of several cultures: the spiced meat dishes were more frequent than spiced vegetarian dishes and these were more frequent the closer to the equator they looked.
Again, the gene-food interaction has been observed in terms of influencing one another and the “ancient pain-sensing pathway interacts with environment, culture and behaviour to shape the degree to which each of us takes pleasure or pain in the eating of chillies”.
Therefore, the answer on the initial question: ‘Why some like it hot?’ is complex. It is in genes, in the culture, the evolutionary advantage due to antimicrobial properties of chillies and the interaction between these factors. On top of that, scientist assume that even the microbes evolve and in time they may become resistant to the current spicing methods so the populations will have to look for other ways how to keep the harmful form of life at bay to protect their own.
Chapter 2: Searching for the ancestral diet
Chapter 5: Discovering why some (don’t) like it hot
Chapter 6: Should we change places, diets or genes?
Chapter 7: Rooting out the causes of disease