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Our Favorite Spice—All About Chili
The chili pepper plant is a many-branched herbaceous perennial that grows up to around twenty-four to thirty-six inches tall. Often having a luxuriant, shrubby look, it is a member of the Solonaceae family, which includes nightshades, potatoes, tomatoes, and eggplants. It has smooth leaves that sprout alternately along each side of its stems and are oval or lanceolate (shaped like spearheads with tapered ends). At flowering, the plant produces bell-shaped white or pale purple blooms containing five stamens, and its fruits are seamless pods that vary in form from round berries to the more characteristic long, thin cases, with a central placenta to which the numerous seeds are attached. Depending on the variety, the fruit ripens to green, yellow, orange, red, violet, or dark brown. Cultivated in temperate rather than tropical climates, it may yield no more than a single crop annually, while some varieties are grown for ornamental purposes only.
Exactly where the wild chili plant first developed remains shrouded in mystery. From residues identified in primeval refuse dumps and in ceramic artifacts, we know that wild chilies were being gathered and used in cooking in Mexico as far back as 7000 B.C.E. The earliest evidence of the chili’s domesticated use by humans, which dates back to around 5000 B.C.E., places it in an area of southeast Mexico that extends over sections of the present-day provinces of Puebla, Oaxaca, and Veracruz. These domesticated plants were descendants of the wild capsicums first encountered by nomadic Mongol peoples who had migrated into the Americas during the last Ice Age, when there was a northern land bridge across the Bering Strait between Asia and North America. As these peoples moved southward into the subtropical and then tropical zones of the continent, they came upon a whole array of wild plant foods, which they began incorporating into their own hunter-gatherer diets.
The fact that settled agricultural communities in Central America eventually began the cultivation of chili peppers, and much else besides, does not mean, however, that this was the chili’s original home. Paleobotanists now think that chilies were carried to this region from the South American interior (most likely the vast tropical savanna zone of central Brazil known as the Cerrado) through a process of natural dispersion, principally by birds that would have consumed them in their regions of origin and then excreted the seeds as they flew north. By this means, the natural habitats of the chili plant expanded gradually into Central America. Unlike mammals, birds are not sensitive to the heat of chilies and do not grind up the seeds when eating them, so they pass whole through the avian digestive system.
There is evidence of the dispersal of cultivated chili peppers across a wide area of northern South America, as well as sites in Panama and across the Caribbean Sea in the Bahamas. Archaeological findings published in the journal Science in February 2007 by a team from the Smithsonian Institute’s National Museum of Natural History, led by Linda Perry, revealed that chilies were being systematically grown and used in cooking as early as around 4100 B.C.E., in sites far distant from the original area of cultivation. Already, then, at this early stage, migrant peoples were transporting their expertise in growing the plant from one area to another and probably also trading the peppers. In many of the residues studied, chili was present alongside maize deposits, suggesting that an early food system combining the processing of cereal grains and chilies had arisen among these ancient peoples.
Four particular strains of the wild capsicum genus had been domesticated in this early era, and to this day most varieties of hot pepper belong to one or another of these four groups. The most widely cultivated is Capsicum annuum, the species that includes the jalapeño, cayenne, and poblano varieties but also the innocuous bell peppers of Mediterranean cuisine. All of these are distantly related to the original wild bird pepper of the Americas, which still grows naturally in the Caribbean, Mexico, and Colombia. After C. annuum comes C. frutescens, which includes the staple Thai pepper variety, the tabasco, the piri piri, the malagueta, the kambuzi pepper of Malawi, the Indonesian cabai rawit, and the xiaomila, one of the foremost varieties in Chinese cooking, grown in the southwest province of Yunnan. C. chinense, a probable descendant of C. frutescens, despite having a Latin name that translates as “Chinese pepper,” originates, as all chilies do, in the Americas. (This misattribution was the slipup of an eighteenth-century Dutch botanist, Nikolaus von Jacquin, who thought chilies were native to China because of their widespread use there. In fact, they had originally been transported to China by European merchants and explorers in the sixteenth century.) Members of the species C. chinense are also known collectively as the bonnet peppers and include the fearsome Scotch bonnet of the Caribbean islands, the Trinidad moruga scorpion, the yellow lantern, the habanero, and India’s bhut jolokia. C. baccatum encompasses the widely used aji variety, as well as lesser-known exotica such as the lemon drop and Brazilian starfish.
A fifth domesticated strain, C. pubescens, is by far the least widely disseminated, and is the only one that was probably not known to the ancient Native Americans. So named for its hairy leaves, it exists only as a cultivated species, having never been wild, and is quite distinct from its relatives. Grown in Peru, Bolivia, and Mexico, it is known respectively as rocoto, locoto, or manzano—the last, meaning “apple,” given the shape of the pepper’s mature fruit.
As well as being a staple food, the chili pepper was likely also put to other uses in ancient times. The acrid fumes it produces when burned, especially in bunches, made this practice a known means of fumigating domestic dwellings in Aztec and Mayan civilizations (bloodsucking insects don’t like smoke), and chili also became an indispensable tool in the pharmacopoeia of the Mesoamerican region. The efficacy of hot spice in clearing blocked sinuses is an experience known to many diners in Thai and Indian restaurants. Long before the modern science of dietetics established the nutritional value of the chili, though, simple observation showed that people who fed on it thrived. We now know it contains significant concentrations of iron, potassium, and magnesium, as well as vitamin A, many of the vitamin B complexes (especially B6), and plenty of vitamin C. It seems likely that the chili found a place in the regional diet because it was one of the few crops that grew reliably at high altitudes, and the fruits retained their pungency when preserved through drying into the winter months. A fascinating aspect of the archaeological study of chilies is that trace elements of the plant have been found in a broad range of cooking vessels, suggesting that chilies were already subjected to a versatile repertoire of culinary uses very early on. Their presence in a vessel known as a spouted jar—essentially a form of decanter for transferring liquids to smaller containers—indicates that they were being used in drinks of one sort or another, as well as in condiments or relishes into which other food items, such as chunks of meat, could be dipped.
The chili plant is versatile enough to have adapted to a wide range of growing climates, and its domestication in various regions was determined by indigenous peoples by the establishment of which strains were best suited to which conditions. Around 1000 B.C.E., when the people known as the Arawak began their millennium-long migration from the northeastern zones of South America to the Caribbean islands—Trinidad, the Lesser Antilles, and Hispaniola (modern-day Haiti and the Dominican Republic)—they brought with them the tropical species of chili that had thrived in the torrid hinterlands of the southern Americas. This was the chili variety widely known as aji among the South American and West Indian peoples, probably C. baccatum. At some later stage—we don’t know precisely when—a second chili species was transported to the West Indies from Central America, this one better equipped for thriving in more temperate climatic zones. It went by a name derived from the language of the indigenous Mexican Nahuatl (Aztec) people, and this is the term that has been in widespread use throughout the Western world ever since: chili. (Nahuatl would in time donate several other food names to European languages, via Spanish, including tomato, avocado, and chocolate.)
What would the chili pepper have looked like at the earliest phase of its domestication? An educated guess can be made in light of the fact that plant historians think that the C. annuum variety known as chiltepin, or chiltecpin, is probably the ancient ancestor of all domestic cultivars. Chiltepin chilies still grow wild across a broad swath of Central and South America, and even in the southern United States. Gathering wild chilies in Sonora Province in northwest Mexico and in the mountainous parts of the southern Arizona desert is an intensive activity that takes place in the fall and winter each year. The chiltepin chili has small round or slightly oval fruits that ripen to orange-red, and it is a hot variety. Its name also derives from the Nahuatl and has its root in tepin, the word for “flea,” indicating something of its tiny dimensions. Despite its modest size, the chiltepin has the same intensity as a fleabite, registering up to around 100,000 on the SHU scale (see pages 18–20 for a full explanation of the heat-measuring systems for chilies). How hot the pepper is when it comes to be eaten depends on the stage at which it is processed: the unripe, green fruit is the mildest and is generally eaten as a condiment pickled in vinegar; the ripened, red, just-picked fruit has distinctly more attack on the palate; the dried, whole version more again; the fieriest of all comes in the form of the dried fruit with its seeds scraped out. Mexican people describe the action of the chiltepin as arrebatado, an adjective that connotes the sense of something snapped up hastily or impulsively, indicative of the fact that while the heat of the chili is certainly scorching enough, it tends to fade quite quickly rather than leaving a prolonged smolder in the mouth.
In some regions, chilies appear to have been reserved for tribal elites, the exclusive delicacy of chiefs and elders rather than the staple food of the common people. Archaeologists in northwest Mexico and the southwestern United States have unearthed charred chili seeds in the presence of luxurious items of jewelry made from copper, turquoise, and crystal, which finding does not necessarily mean that subaltern folk didn’t eat them, too, but does suggest that chilies were an indispensable element of the lifestyle of the privileged. However, these areas probably began to produce domesticated chilies on a significant scale only after the arrival of Spanish colonialists in the early sixteenth century, so perhaps the chilies that appear in the much older garbage deposits in the Chihuahua province of Mexico were the product of a very restricted pre-Hispanic cultivation for the upper echelons of society only.
The fact that, in certain areas, chilies had become the food of elites anticipates the role they would come to play in the cosmologies of indigenous peoples, which we shall look at in greater detail in part 2. Whereas the chili pepper became a currency in simple barter economies, it took on a more exalted role in the myths of the Aztec, Toltec, Mayan, and Incan peoples over the centuries. Searching for the explanation in the distant prehistory of chili cultivation, we need only imagine the effect that these pungent, fiery little pods might have had on palates that had not encountered anything like them before. The standard diet of much of pre-Columbian America consisted of maize, beans, and squash. Against the background of these nutritious but essentially very bland ingredients—grains, pulses, and fleshy gourds—the sizzling heat of chilies transformed the eating experience into something else entirely. They have a digestive effect as well: the saliva produced by eating chilies is rich in the enzyme amylase, which helps to break down the sugars in starchy foods into more assimilable glucose. Chilies were, and are, a quintessential seasoning, a gift from the gods as indispensable as salt, and the grisly prospect of a life without them elevated them at an early historical stage to the status of the sacred.
The pugnacious flavor of chilies made them well-suited to perform combat and defense roles in indigenous mythologies. They were used not only to ward off evil spirits and more terrestrial pests, but also in counter-magical rituals to guard against the effects of the “evil eye,” the maleficent intentions of enemies. Protective strings of dried chilies known in Spanish as ristras were draped on the external walls of houses or worn as necklaces, a kind of spiritual armor against the attentions of demons and vampires that anticipated the symbolic role that garlic—another pungently enlivening food seasoning—would play in many European cultures.
The wide range of culinary and symbolic uses to which people have put chilies remains quite strange when set against one rather obvious fact: The chili pepper’s biological makeup is telling humans, and other mammals, that it does not want to be eaten by them. So how did it come to develop such an aggressive nature, and how did humans manage to overcome its aversive signals?
How the Chili Came to Be Hot
The heat in chili peppers comes from a naturally occurring substance called capsaicin. On the tissue of many mammals, including human beings, capsaicin produces a burning sensation that gives the impression that some level of damage is occurring. It has this effect because mammals are equipped with a sensory pathway known as the transient receptor potential (TRP) channel. On contact, capsaicin binds with this channel and activates an alert signal that deceptively convinces the organism that it is being burned, typically at around 108°F (42°C). We’ll look at the biology of this effect in more detail in the next section, but for now, the question arises as to why and how the chili plant developed this defense mechanism.
The most obvious advantage of capsaicin is that it deters mammals with grinding molars from eating the pepper plant and destroying its seeds or reducing them to a state where they are no longer capable of germinating. Birds, which lack the TRP channel and are consequently not sensitive to the searing heat of chilies, will feast on the ripe fruits to their stomachs’ content, in due course dispersing and propagating the unharmed seeds in their excreta. This process is how the chili pepper spread northward from its original home in South America. But an interesting question remains: What influences some plants to produce hot chilies while others remain devoid of spice?
In 2001, a team led by Professor Joshua Tewksbury conducted a pathbreaking study in southeastern Bolivia, the wild chili’s original heartland.1 What influences the development of capsaicin in wild chilies is not necessarily the behavior of either rodents or birds, but that of an order of insects belonging to the Hemiptera family known as the true bugs (cicadas, aphids, leafhoppers and their relatives). These insects also feed on wild chilies, using their pin-sharp proboscises to pierce the fruit of the pepper and ingest the juice inside. It appears, however, that these insects are as sensitive to capsaicin as mammals are, since after initial investigation they will reject those chilies that are hot. Tewksbury’s team found an obvious correlation between the highest incidence of insect puncture marks and a lack of spiciness in those particular chilies. So what might the significance of that conclusion be?
When chilies are punctured in this way, the humid conditions prevalent throughout these tropical zones allow airborne fungi to enter and infect the plant. Molds form on the seeds and gradually kill them—unless, that is, the plant can manufacture its own defense against the fungus. That is where capsaicin comes in. The fungal growth cannot withstand attack by capsaicin, as Tewksbury’s team confirmed when they replicated this process in the laboratory. As more capsaicin was progressively introduced, the molds had less chance of surviving. In drier areas, where there is naturally less humidity and smaller insect populations, there are more non-spicy chilies because the plants do not have to defend themselves from molds to the same degree. By contrast, in the more humid regions, where there are more insects creating more damage and allowing the pepper plants to become infected with fungus, there are more naturally occurring hot varieties.
What this means is that, even before birds and mammals entered the equation, a combination of local climatic conditions, insects, and naturally occurring fungi had already begun to determine which plants produced spicy fruits. And it seems likely that ancient native peoples discovered that those plants that showed the fewest puncture holes would be the spicy ones, and so they began gathering, then cultivating, those varieties as part of their diet.
What led humans to develop a taste for the spiciest peppers, though? Could it be that these primordial palates were as discerning in their food preferences as that of any modern-day restaurant critic? Against that rather fanciful hypothesis, a far more practical explanation suggests itself. What attracted early Americans to the spicier plants was their observation that the hotter varieties contained less or no fungus. In other words, they came with their very own built-in food preserver. Long before temperature-controlled food preservation was possible, the spicy chili’s antimicrobial properties helped to preserve not just the pepper itself, but any food mixed with it. This quality makes chilies practically useful for storing food in leaner times, but it also has a medicinal implication. Microbial infection in food was a common cause of serious illness, even death, in primeval cultures, and it can still be deadly where preservation technologies are sorely lacking. Since capsaicin in chilies was a powerful counteragent to such infection, humans may have adapted as they evolved to develop a taste for spicy hotness. If this is true, as Tewksbury’s team proposed, then the domestication and eventual spread of chili peppers is a prime example of humans’ and plants’ evolutionary developments marching in step with each other.
Capsaicin
The primary compound in chili peppers that produces the burning sensation is capsaicin. It is the hottest and most prevalent of a half-dozen related components in chilies, known collectively as capsaicinoids. Around 70 percent of the heat in hot peppers comes from capsaicin. In its pure form, capsaicin is about one hundred times hotter than the average scorching habanero chili, if such a thing can be imagined—about sixteen million SHU.
Attempts to isolate the active component in chili peppers progressed rapidly in the early nineteenth century. In 1816, a Swiss researcher, Christian Bucholz, partly isolated an impure form of capsaicin from dried Spanish chilies and proposed naming it capsicin after the plant genus Capsicum. Scientists in Germany, France, Denmark, and Britain made further progress in analyzing the component through the 1820s, but it was not until 1876 that capsaicin was extracted in its almost pure state by a British chemist, John Clough Thresh, and given its present name. The absolutely pure form was finally isolated in 1898 by German scientist Karl Micko, whose findings appeared in a publication invitingly entitled the Journal for the Investigation of Necessities and Luxuries. A full understanding of the chemical composition and structure of capsaicin began to be formulated in 1919 by American chemist E. K. Nelson, following which his compatriot Stephen Foster Darling, in conjunction with an Austrian researcher, Ernst Späth, first prepared synthetic forms of it in 1930. The other, related capsaicinoids were discovered only in 1961, by a team of Japanese scientists.
According to a persistent popular myth, most of the capsaicin is in the seeds of chili peppers, which is why Western chefs often roughly chop chilies and add the lot—seeds and all—to the dish they are cooking. Jalapeño slices bristling with seeds are a common sight among pizza toppings. In fact, the seeds contribute very little, other than looking a bit messy. They can be scraped away once the chili is split without any loss of heat. The greater part of the capsaicin is instead concentrated in the pith, or the white membrane that holds the seeds in place. Since the seeds are obviously in contact with that, they will pick up some of the membrane’s heat, so recipes that tell you to avoid scraping out the seeds in the interest of maintaining heat are not entirely misguided. It’s tricky to get rid of the seeds without also getting rid of the pith, but not impossible. On the other hand, the common instruction to remove the seeds if you want to diminish the heat of the chili is all but pointless. The reason that the heat is concentrated in the membrane is explained by the plant’s evolutionary biology. When chilies developed capsaicin as a method of combating fungus, they concentrated it in the very part of the fruit where the mold was most likely to develop. There is also some heat in the flesh of the chili itself, as you will discover when you put a tiny snippet on your tongue to test it. If that’s all the pepper going into your recipe, you will still get lots of heat in the finished dish. For that extra kick, though, include at least some of the pith.
In its pure state, capsaicin is a partly crystalline compound that is colorless, odorless, and either oily or waxy. While it is legal to buy on both sides of the Atlantic in either liquid or crystalline form, the European Union banned capsaicin from use as a food additive in January 2011, although essential oils in which it occurs have not been proscribed. As the packaging will sternly inform you, capsaicin should be handled only with protective gloves and with something to shield your eyes, too. Adding it in droplets to your cooking is a high-risk venture, but what else are you going to do with it?
Measuring Capsaicin
Because the range of heat in chili peppers—cultivated varieties as well as those growing wild—is so variable, a biological trait scientifically known as polymorphism, it was inevitable that, sooner or later, somebody would devise a measurement system for calibrating it. The first such system, and one that is still in use today, was devised by Wilbur Lincoln Scoville, an American pharmacist born in Bridgeport, Connecticut, in 1865. It was while working at the Parke-Davis pharmaceutical company of Detroit in 1912 that he formulated what became known as the Scoville Organoleptic Test, a method for determining relative levels of spice potency in different types of chili peppers.
What is interesting about the Scoville scale is that it relies on a fundamentally subjective act of judgment. To establish the heat level of a pepper, it is first dried and then infused in alcohol to extract its capsaicinoids. These are then diluted in a sugar solution in decreasing concentrations, and the resulting preparations are then tasted by a panel that usually consists of five tasters. The dilution of capsaicin carries on until a majority of the tasters—at least three—can no longer detect any heat. Whatever level of dilution is necessary to reach that state is then expressed as a numerical value: For example, dry pepper extract that has to be diluted with half a million times the quantity of solution would be given a reading of 500,000 SHU.
It isn’t difficult to see possible objections to such a procedure. First, one person’s “pretty hot” might be another’s “fairly mild,” so some means of standardizing the tasters’ own judgment criteria needs to be established first. Second, individual tasters have widely different concentrations of heat receptors on their tongues. Some people are just naturally more sensitive to chili hotness than others.
Since the palate rapidly becomes desensitized to levels of chili heat over an intensive period of tasting, the system subjects tasters to only one pepper sample at a time. That last point might be familiar to anybody who has gone from stall to stall at a chili fair, tasted the different products, and found fairly quickly that they can no longer distinguish the average hot from the sizzling hot. There is another possible flaw in this procedure, though. Given that the Scoville test involves trying to detect smaller and smaller concentrations of capsaicin in solution, many tasters’ palates would likely become desensitized to levels of capsaicin that they would readily pick up if they were tasting the solutions completely fresh.
Despite its many imprecisions, however, the Scoville scale endured through most of the twentieth century in the absence of any more reliable system. Developed in the 1980s, a technique called high-performance liquid chromatography offers a more objective way of assessing relative heat. By a process of pressurizing the capsaicin solution through a column containing a solid, adsorbent surface, the various components in the solution are separated and analyzed for their intrinsic heat capacities. It’s the same process used to test for performance-enhancing drugs in the urine samples of athletes. The measurements are expressed in pungency units defined by the American Spice Trade Association (ASTA). One ASTA unit is equivalent to about 16 SHU. So a Tabasco pepper with a rating of 32,000 SHU would convert to roughly 2,000 ASTA pungency units. Any conversion table between the two scales will be imprecise, though, to the degree that the Scoville system itself is imprecise.
That said, SHU readings are still what the hot pepper industry prefers for measuring the hotness of its products, from raw peppers to chili pastes and relishes, and so, notwithstanding the caveats expressed above, that is the system I use in this book.
How Capsaicin Works
The reason that contact with chilies produces painful sensations in tissue is, as explained above, that capsaicin effectively tricks the organism into thinking it is being burned. It does this by binding to a receptor in our sensory neurons known in the scientific shorthand as TRPV1, or transient receptor potential vanilloid type 1. (Capsaicin is a member of the vanilloid group that also includes the primary component of vanilla beans.) This group of receptors is principally what enables the body to detect extremes of temperature, the contact of acidic or corrosive substances, or the effect of any kind of abrasion or chafing. That message, when transmitted to the brain via TRPV1, persuades the neural system that the organism is undergoing damage and alerts it to avoid the source of harm. It’s the reason you jerk your hand away in a split second when it accidentally makes contact with a hot surface. Although it seems hard to believe when your mouth is on fire, no direct tissue damage results from eating chilies or hot dishes spiced with them. In every other respect, though, the brain is fooled into reacting as it does to intense heat: with sweating, facial flushing, and the dilation or widening of blood vessels, resulting in reddening of the tongue. While these properties have been enough to deter other mammals, reptiles, and insects from eating hot peppers, humans with their highly evolved intelligence began to see through the delusive effect in ancient times. The fact that chilies were domesticated in five separate zones, resulting in the five principal species of Capsicum, is evidence that, long before the science was understood, human beings had learned systematically to disregard the aversive signals that the chili plant was sending out.
For some people, it should be made clear, the distress caused by eating or just coming into contact with chilies is all too real. It is possible to be allergic to them, so that consuming them may result in skin rashes and other forms of dermatitis. People working with chilies in large-scale food processing without skin protection have often developed a painful dermal inflammation known as Hunan hand syndrome: the condition is named for the spicy cuisine of the Chinese province, since it was first identified among Chinese restaurant workers tasked with rubbing the skins off roasted chili peppers. An excess of chili heat can also produce gastric disturbance—anything from a persistent attack of hiccups to vomiting and diarrhea. Only trial and error will establish where your own personal limits lie, and in some cases avoiding chilies altogether may well be the safest option.
The immediate antidote to the flaming pain of hot chili in the mouth is anything containing dairy fat. Cold milk, yogurt, or—best of all—ice cream soothe the burn because capsaicin is soluble in fats, and the milk protein casein, which is present in all dairy products, acts like an extinguisher on the fiery compound. Oils can also do the trick, and so can alcohol, counterintuitively, because capsaicin is soluble in ethanol. A mouthful or two of cold white wine can be just as effective as milk, and a nibble of bread makes a good absorbent material, mopping up capsaicin from the mucous membranes. What doesn’t work, as so many have discovered to their frustration, is water, since capsaicin is hydrophobic and not soluble in water. If the water is iced or very cold, holding it in your mouth may briefly seem to soothe the burning, but it returns in full force as soon as you swallow. Milk is the way.
The burning sensation of chili may be an excitement or a torment, depending on your attitude toward acute gustatory discomfort, but capsaicin also appears to have beneficial effects on the human organism, too. In response to the painful stimulus, the brain releases a flood of biochemicals called endorphins, which are its natural painkillers. They work by inhibiting the ability of nerves to transmit pain signals to the brain, and like many pharmaceutical pain relievers—primarily opiates—they thereby produce a sense of tremendous satisfaction and even pleasure. This has led to the suggestion that people who eat a lot of hot, spicy food are in pursuit of what has been called, drawing on the language of illicit substances, the “chili high.” Could it be that people who claim to have developed a chili habit are actually seeking the endorphin high that capsaicin provokes? When you factor in the evidence that capsaicin consumption also releases another potent neurotransmitter, dopamine, responsible for feelings of well-being and general contentment, it becomes a little easier to understand some people’s apparently masochistic devotion to setting their mouths on fire. We shall return to these questions in detail in part 3.
The only problem with the endorphin and dopamine effect is that it operates according to the law of diminishing returns. When serious chiliheads constantly seek out the next hottest thing on the market, or when they intensify the chili pepper quotient a little more every time they cook themselves a batch of chili con carne, they may well be trying to re-create the power of the original experience as it progressively diminishes. This is what Shakespeare’s Sonnet 52 characterizes as “blunting the fine point of seldom pleasure.” Enjoy it too much, and it becomes gradually less enjoyable, so that more is required to achieve the same effect, thereby progressively devaluing the original pleasure.
On the other hand, there is no need to worry that a serious chili habit will blunt your receptivity to pleasure-triggering brain chemicals. It isn’t just pain that triggers endorphins. Vigorous physical exercise, sexual activity, and even laughter are also known to produce the pleasurable response, and only a Grinch would recommend limiting those.
Chilies and Health
In the twenty-first century, inflated claims about the various positive and negative links between diet and health are par for the course. Those who are concerned about eating right are bombarded almost daily with extravagant theories about this or that ingredient, often the basis for entire outlandish dietary systems promising to add years to our lives and shave inches off our waistlines in the process. Such diets come and go with the tides of fashion, and yesterday’s cure-all regimen is today’s hocus-pocus. Is anybody still on the grapefruit diet? What we can establish about the health benefits of eating chilies, and spice-rich food in general, should be treated with due caution, and even now, much of it awaits further dietetic evaluation.
What we can say with certainty is that chilies contain many beneficial nutrients. As we saw above, a typical raw, red chili, being a plant food, is a good source of dietary fiber, and it contains high concentrations of vitamins B1 (thiamin), B2 (riboflavin), B3 (niacin), and B9 (folate), as well as excellent levels of vitamins A, B6 (pyridoxine), C, and K. As for minerals, the chili has useful amounts of iron, magnesium, phosphorus, and copper, and is a very good source of potassium and manganese. All of these vitamins and minerals have essential roles to play in the human diet, and their high concentrations are what helped our distant ancestors to thrive. Chili peppers are low in sodium and contain zero cholesterol, though a ripe fruit does contain about five percent sugars. One standard pepper, weighing about 1.5 ounces (42 grams), contains around 18 calories.
On the strength of this nutritional data, we can say with confidence that a chili-rich diet can assist with fighting infections, create and maintain collagen to keep hair and skin looking radiant (through antioxidant vitamin C), regenerate cells throughout the body, and promote the formation of red blood cells in particular (iron and copper). It helps maintain healthy eyesight and guards against age-related macular degeneration (vitamin A), decreases blood pressure and regulates healthy blood circulation through the relaxation of blood vessels (vitamin B9 and potassium), and promotes the production of good, high-density cholesterol in the body, boosting cardiovascular health by helping to break down the bad, low-density type (vitamin B3).
Considering all of these factors, research teams all over the world have in recent years been conducting experiments to assess the health and life expectancy of populations that eat plenty of chili. According to a study published in the British Medical Journal in August 2015, a team at the Chinese Academy of Medical Sciences, working with a study group of 500,000 subjects over seven years, found that regular consumption of chili peppers prolongs life expectancy proportionately with frequency of ingestion.2 The team found that people in the observational target group were less at risk of premature mortality from the big worldwide killers—heart disease, stroke, cancer, diabetes, and respiratory system disorders—if they regularly ate spicy food than if they didn’t. The risk was 10 percent less for those who ate spicy dishes once or twice a week, 14 percent less among those who ate them most days or every day. The results were equal between men and women. An editorial accompanying this report noted that more work was needed to establish whether there are consistent pathways between these medical factors and the consumption of chili, but that the observational data looked very encouraging.
As we saw earlier, capsaicin has strong antimicrobial properties, inhibiting the growth of fungus within fruits that have been punctured by insects, but also helping to preserve other foods that have been spiced with chilies. It gives chili-rich food an antibacterial advantage, protecting the consumer from infection and also inhibiting the spoilage of other food. Capsaicin is known to be lethal to around 75 percent of all food-borne pathogens, making food poisoning from spicy dishes considerably less likely than from nonspicy ones.
Two studies in 2015 gave sustenance to the long-held hypothesis that chili is a preventive factor in obesity. A team of biophysicists at the University of Wyoming found that the capsaicin molecule increased metabolic activity in mammals, causing their systems to consume more energy and preventing weight gain even in cases of relatively high-fat diets.3 (The mammals tested, it should be added, were mice.) Perhaps even more pertinently, research at the University of Adelaide, Australia, established that capsaicin binds to receptors in the stomach lining to produce the feeling of satiety.4 We can all, perhaps anecdotally, attest that very hot food seems to exhaust the appetite sooner than blander food does. The Adelaide findings suggest that this sensation is accounted for by more than just the effect of the burning sensation on the tongue and palate.
In 2012, a team working at the Chinese University of Hong Kong found that capsaicin breaks down bad cholesterol by promoting the good variety and helps to dilate blood vessels to improve blood flow.5 At the time of this writing, the most encouraging recent findings have come from a pair of researchers at the Robert Larner, M.D. College of Medicine at the University of Vermont, Mustafa Chopan and Benjamin Littenberg. Reported in January 2017 in the multidisciplinary scientific journal PLOS ONE, their survey of more than sixteen thousand adults in the United States corroborated the Chinese findings reported two years earlier in the British Medical Journal. That is, risk of untimely death, both from specific causes and from any cause at all, was reduced by a factor of about 13 percent in those who regularly consumed chilies.6 Whereas the 2015 study looked at Chinese adults only, the Vermont project considered people from a variety of ethnic backgrounds, so the more recent research, as the authors put it, “strengthens the generalizability” of the earlier findings.
On the other side of the coin is a body of more nebulous, but nonetheless concerning, research about the possible drawbacks of the overconsumption of chilies. A paper titled “The Two Faces of Capsaicin,” published in the journal Cancer Research in April 2011, suggested that overuse of capsaicin-based skin creams for pain relief may be linked to an increased risk of carcinogenesis, resulting in skin cancers.7 Creams, gels, and capsaicin patches have been used in recent years to treat a wide variety of pains, ranging from temporary postoperative pain to the chronic discomforts of osteoarthritis, rheumatoid arthritis, and neuralgia. The medical logic of these treatments is based on the desensitization that builds up after repeated exposure to capsaicin, so that applying a capsaicin cream eventually reduces susceptibility to pain, an effect that is unique among naturally occurring, irritant plant compounds. Whereas the authors of this paper, Ann Bode and Zigang Dong, suggested that the excessive use of topical capsaicin in creams may have adverse effects, their summary states that the normal consumption of chili peppers in food is “not equivalent” to capsaicin’s application on the skin. In other words, the possible carcinogenic effects of dermal creams do not translate into a similar risk from eating chilies.
Given the searing heat that consuming chilies generates not just in the mouth but throughout the digestive system, it seems obvious that anybody suffering from a gastric disorder—a tendency to inflammations in the throat or stomach—or a gastric ulcer should avoid very spicy food. But as to whether spicy food can cause these conditions in the first place, the medical jury is very much still deliberating.
What is certainly true for many unfortunate people—and this really is one of those only-one-way-to-find-out dilemmas—is that hot food can trigger digestive spasms, contractions of the intestine that indicate to the body that it has consumed a severe toxin that it must get rid of as soon as possible. (Hello, diarrhea and vomiting.) If you have this sort of reaction at a certain level of chili intensity, you will not necessarily experience the same thing at lower doses; you only need to find your level—the problem then being that, if you haven’t cooked the dish yourself, you don’t know until you start eating it whether it’s going to tip you into the discomfort zone.
Some animal trial studies have tenuously suggested that too much capsaicin can be a precursor to stomach or liver cancer. Two Korean studies from 1985 and 1991 appeared to suggest as much, but in 1998, a Japanese team feeding mice substantial quantities of capsaicin and a related compound for eighteen months found no evidence of carcinogenic activity in any of the subjects.8 The alternative conclusion, that capsaicin may even be a protective factor against the development of cancerous cells, has not been decisively validated, either. On the question of whether chilies corrode the stomach lining, one set of endoscopy tests conducted in 1987 showed severe irritation and even gastric bleeding. Another set conducted the following year, involving two of the same scientists from the first test, found no evidence of harm whatsoever, even when chili—in the form of ground, dried jalapeños—was introduced directly into the stomach rather than first passing through the esophageal tract.
Perhaps the final say in the matter should be given to the incontrovertible fact of human dietary evolution. If chili peppers were ultimately bad news for us, we probably would not have been eating them for millennia. They certainly would not have been carried around the world and been adopted in a broad range of food cultures in both hemispheres, to the extent that they have.
My guess is this: If you’re still reading, you’re probably not unduly worried that chilies are bad for you. Neither am I.
Copyright © 2018 by Stuart Walton
