The hot topic

A few times every year, and without too much effort, you’ll find articles about the “hows and whys” of liking for hot (spicy) foods. Most recently, there was “Learning to Like Spicier Food” and “What’s Driving the Global Chili Pepper Craze” in the USA magazines The Atlantic and Forbes, respectively [both featured conveniently in Taste Matters on Flipboard]. Now, I’d like to be able to say that these particular articles actually revealed the drivers of the chilli ‘craze’ or the exact mechanisms of chilli liking. However, scientists such as Paul Rozin attempted to answer both questions some years ago [1], but without reaching an obvious conclusion, and the same questions continue to be raised.

Chilli is not like other foods. We don’t, for example, tend to see long articles exploring the conundrum of ice cream or chocolate preferences. It’s fat and it’s sugar and they’re delicious …. what’s the issue? Chilli, on the other hand, contains compounds that, when they aren’t being added to foods, are being sprayed into the faces of criminals, students and other less desirable members of society. Indeed, the effects in both cases are not entirely dissimilar: tearing, pain, facial flushing and excessive salivation. In neither case, does our body seem to be welcoming a dose of capsaicin.

And yet …. chilli, from its origins as a relatively localized crop in central and south America, has become the most used spice worldwide, and the second most added food ingredient after salt. We can’t all be masochists, surely? There are two questions to answer. The first of these is why any individual would voluntarily eat something that was painful. Secondly, why have so many societies – Korea, Mexico, India, Vietnam, Thailand, amongst many others – made hot spices a central part of their cuisine’s
flavour principle? These are not the same question, but on a different scale. In very many societies, sections of the population eat odd things – oysters, natto, Vegemite – without such delicacies taking over the world.

A variety of explanations have been proposed to attempt to explain the ubiquity of chilli and other pungent spices (pepper, ginger, cinnamon, mustard). These include that fact that the chilli plant is a fast growing source of vitamins, especially C and A; that it increases salivation and hence better digestion of foods; and that it promotes perspiration and thus heat loss in warm climates. These all sound plausible reasons, but they lack any evidence to support them [2].

There really is no obvious connection between the cuisines of those countries that have adopted chilli, nor any obvious difference between those that are and are not especially spicy. Why Korea and not Japan, for example? Had Japan not been resistant to foreign influences until relatively recently, would its soba be spicy? Geographical isolation aside, one clue to the widespread uptake of chilli may lie in the nature of dietary staples in chilli consuming countries. In Mexico, the cuisine is based on corn, in South-East and other parts of Asia, rice – both bland staples. It may be that chilli provides a way of providing interest and flavor impact to otherwise somewhat monotonous diets.

To be convincing though, this argument needs to apply elsewhere, rather than in just warm-climate cultures and their chilli-dominated cuisines. The expeditions of Christopher Columbus to central America are widely regarded as the source of the introduction of chilli to the rest of the world. It is useful to recall why he was sailing in the first place, and that is to find a convenient route to the sources of spices in Asia. In other words, spice-wise he really was very lucky. Europe as a whole proved a tough sell for chilli, but it is unclear why. It may have been the growing climate as much as the heat of the fruit itself. Certainly, chilli is still used in countries such as Spain, Italy and parts of central Europe. Hungary, of course, took the hot chilli and converted it in hot and mild versions of its national spice, paprika. Even Britain has a history of applying other pungent spices to foods with its traditional use of hot mustard and horseradish, and now curries from the subcontinent being the most popular restaurant foods. In the USA, hot sauces are more popular than ketchup. Hence, even in countries where dietary variety is not an issue, spiciness continues to increase.

It is well known that both flavour impact and complexity in foods are valued, making foods more pleasurable. Pungency in its many forms provides both. Adding bubbles to soft drinks, heat or cooling to foods, and bite to alcohol are all ways of engaging a completely distinct sensory system, mediated by the trigeminal nerves in the tongue, palate, nose and eyes. While this system contains pain fibres, it also responds to other tactile and temperature sensations that can enhance and amplify tastes and odours.

Even when the burn of a hot dish becomes a little too impactful, and the body produces defensive responses such as salivation and flushing – we are aware that it is harmless. In high chilli-consuming countries, the spice is introduced to children gradually in the secure context of family meals, and there is therefore no anxiety associated with the pain.

Another piece of evidence supporting idea that chilli is used for flavour impact is the change in response to the burn over time. Regular chilli eaters do show a reduction in burn intensity, but this is minor, and they are not immune from the burning sensations – rather, they actually learn to enjoy them, even if it seems too hot at first [1]. Interviews with both Americans and Mexicans who were asked why they liked chili showed that the majority referred to the piquancy, or the enhancement of flavor of food. Many interviewees claimed to be as sensitive as always to chili, but that they had come to like the hot sensation that they originally disliked. This is also consistent with a view that chilli consumption represents “benign masochism” – effectively getting enjoyment from pain because we know it is harmless.

A variety of explanations have been put forward to explain the high levels of enthusiasm with which many of us take to very spicy food. It is no surprise to find that real chilli enthusiasts are also “sensation seekers” for all sorts of sensory stimulation. One enduring popular notion is that the burn of chilli releases the body’s own opiates, or endorphins, perhaps via the release of a neurotransmitter called
Substance P (which is released in response to pain). The idea is that chilli eating – followed by a little squirt of the body’s own heroin – produces a feeling of well-being could reinforce a sort of spice addiction. Attempts to demonstrate this have yet to produce any evidence for such a mechanism, but it is at least consistent with findings that chilli burn is reduced by sweet tastes, and vice versa [3]. The pleasantness of sweet tastes are also thought to be mediated by endorphins, and it is well known that sweetness can increase tolerance for pain [4].

1. Rozin, P. and D. Schiller, The nature and acquisition of a preference for chili pepper by humans. Motiv. Emot., 1980. 4(1): p. 77-101.
2. Prescott, J. and R.J. Stevenson,
Pungency in food perception and preference. Food Rev. Int., 1995. 11(4): p. 665-698.
3. Prescott, J., S. Allen, and L. Stephens,
Interactions between oral chemical irritation, taste and temperature. Chemical Senses, 1993. 18(4): p. 389-404.
4. Barr, R.G., et al.,
The response of crying newborns to sucrose: Is it a “Sweetness” effect? Physiol. Behav., 1999. 66(3): p. 409-417.