100 Million Years of Food, page 11
DOPPELGANGERS: Sometimes we eat noxious plants because of mistaken identity. The toxin from water hemlock, a plant sometimes confused with wild parsnip, wild carrot, wild celery, artichokes, sweet potatoes, or sweet anise, triggers spasms violent enough to make people bite through their tongues and smash apart their teeth.12 Another example of a doppelganger is meadow saffron, which may pass for onion; eating meadow saffron triggers thirst, diarrhea, stomach pain, delirium, and death in half of all cases. It may take up to three days for death to deliver merciful deliverance.13
SORCERERS: Certain plants may be fatal to consume, but we attempt to employ them in small doses as medicines. Dieffenbachia, the houseplant mentioned above, was chewed by males in the Caribbean Islands to achieve temporary sterility lasting up to two days. Bitter melon, a fruit commonly found in Asia and in Asian grocery stores elsewhere, is anecdotally reported to improve symptoms of diabetes. In 2010, an Indian scientist reportedly died from drinking a particularly bitter concoction of bottle gourd and bitter gourd juice, a regimen that he had maintained for four years. His wife also drank the juice, but survived after vomiting blood and experiencing severe diarrhea.14 Bitter melon, cucumbers, and squashes concoct a bitter compound called cucurbitacin to protect themselves from insect and fungal attack. Although domesticated versions of these plants were bred to reduce their bitterness, when cucurbitacin is present in high concentrations, the bitter taste—gardeners are familiar with the bitterness of cucurbitacin in homegrown cucumbers near the stem end—normally compels people to stop eating before they become ill.
FALLBACKS: Sometimes, poor people are forced to subsist on noxious plants out of hunger and poverty. Lathyrism, a disease that leads to back pain and paralysis of the lower limbs, results from prolonged diets of grass pea.15 Under conditions of poverty, famine, and interruption of agricultural work, people consume the hardy grass pea plant as a last-resort food item. Lathyrism debilitated thousands of people in northern India, and outbreaks occurred during hardships such as the Spanish Civil War (1936–39), among Romanian Jews confined to concentration camps, Greeks besieged by the Germans during World War II, and German inmates in France just after the close of World War II.16 Lathyrism may not just be a problem in Europe and Asia: Christopher McCandless, the young American itinerant whose life was recounted in the popular book and movie Into the Wild, may have died from lathyrism incurred by eating wild-potato seeds while attempting to live off the land in the Alaskan woods.17
WEREWOLVES: Some plants are only troublesome at certain stages in their life cycles. In the fall of 1978, up to three hundred boys at a southeast London day school sat down for lunch, choosing from a menu of potatoes, steak pie, gravy, cabbage, tinned carrots, and dessert of apricot and syrup sponge pudding, with or without custard. By eight o’clock that evening, seventy-eight of the boys began to vomit and experience severe diarrhea and stomach pain. Seventeen boys were taken to the hospital; they developed fever, and their feces turned green. Three boys fell unconscious, and two spoke gibberish when they regained consciousness. Fortunately, by the eleventh day, all the boys had recovered enough to be discharged. The one food that all the stricken boys had eaten in common: potatoes. Domesticated potatoes have been bred to reduce the steroid alkaloid solanin to palatable levels, but tubers that are exposed to sunlight (thus making them vulnerable to being eaten) and turn green, or that have been attacked by disease or left to spoil, may produce dangerously high levels of solanin. Since solanin tastes exceptionally bitter, fatal poisoning by potatoes is uncommon, but it does occur, such as during the Korean War, when large segments of the North Korean population were reduced to subsisting on spoiled potatoes. Investigation into the London case suggested that the affected boys had consumed potatoes from an old bag that had been left over from the term prior to the summer.18
COMRADES: Finally, we arrive at our plant BFFs (best friends forever), the vegetables, legumes, and cereals that we find in grocery stores, in our garden plots, and on our farms. These are the foods that most nutritionists recommend that we heap onto our dinner plates, lightly cooked or processed, if at all. Traditional societies certainly valued plant foods like these, but they were careful to process and cook them in ways that reduced their harmfulness. The chief benefit of our companion plant foods is that they do not poison us—not outright, anyway. Let us consider some of the defensive compounds that our everyday plant foods attempt to deploy on predators like ourselves.
Some defensive compounds cannot be reduced by cooking. For example, celery, parsley, and parsnip stock up on furanocoumarin, a compound that protects plants against insects but also can cause skin rashes in people who handle these plants (though eating celery does not present this problem). The skin rashes can be a hazard for field workers and are worsened when exposed to sunlight. Ironically, breeding for celery varieties that are more resistant to insects or fungi may inadvertently ramp up the concentration of furanocoumarins.19 Saponins, a defensive toxin deployed in chickpeas, soybeans, beans, peanuts, spinach, and asparagus (and also in sea cucumbers), are soaplike compounds that create a bitter taste and irritate mucous membranes. Saponins are toxic to cold-blooded animals such as insects and fish and are used around the world as fish poisons. Normally saponins cannot pass through the gut wall of humans. However, if for some reason saponins enter the bloodstream, such as through an injury to the gut, they can cause rupturing of the blood cells (hemolysis). Symptoms of saponin poisoning include dizziness, headaches, chills, irregular heartbeat, convulsions, and coma. Like furanocoumarins, saponins are fairly resistant to cooking or most other techniques of food processing, with the exception of fermented foods like tempeh (Indonesian fermented soybean), which have substantially reduced saponin content.20 Isoflavones, compounds that resemble and mimic the properties of estrogen, are produced by soybeans and to a lesser extent by other plants from the legume family, including alfalfa and clover. Animals that browse too much on isoflavone-rich plants, such as ewes feeding on clover, can become sterile, due to the disruptive hormonal effects of isoflavones. Soy-based formulas can interfere with steroid metabolism in infants. Like furanocoumarins and saponins, isoflavones are resistant to cooking.
In other cases, cooks in traditional societies learned how to make a good meal out of well-defended plants through ingenious food preparation techniques. Legumes (beans, soybeans, lentils, chickpeas, etc.) fortify their seeds with lectin compounds that cause gastrointestinal distress when consumed in large quantities, as well as growth reduction and liver damage.21 Protease inhibitors are a class of defensive compounds manufactured by legumes, cereal grains, and potatoes to prevent plant predators from being able to digest their foods. Hard-pressed peasants figured out that concentrations of lectins and protease inhibitors are reduced through food preparation methods such as sundrying, pan-frying, deep-frying, roasting, soaking, boiling, and fermentation.22 Cassava is problematic due to cyanide compounds; populations in tropical countries that rely on cassava as a staple may suffer from cyanide poisoning, goiter, or neurodegeneration. Traditional methods of making cassava safer to eat include sundrying, soaking, grating, and roasting. Lima beans, sorghum, and bamboo may also induce cyanide intoxication. Clever tricks to reduce cyanide content include grating, chopping into smaller pieces, drying, boiling, prolonged submersion in warm or hot water, steaming, roasting, and fermentation.23 (Boiling should be done uncovered, to allow cyanide gases to escape completely.)24
There are also plant parts that are not built specifically for defensive purposes but can still damage the health of predators. Like an attractive best friend who mesmerizes your potential dates, phytates are storage forms of phosphorous that bind to minerals and therefore have the tendency to deplete our bodies of essential minerals such as calcium, magnesium, zinc, and iron. Soybeans, beans, cashews, sesame seeds, pistachios, chickpeas, peas, apples, eggplants, tomatoes, and papayas contain phytates. Oxalates, which may also steal your calcium and other minerals and are a risk factor in developing kidney stones, are abundant in spinach, okra, chocolate, couscous, whole-meal rye, whole-wheat bread, durum wheat, and especially wheat bran. Dehulling, soaking, cooking, and sprouting are common food preparation methods that reduce phytate content, while oxalate levels in foods are reduced by dehulling, boiling, steaming, baking, breadmaking, and fermentation.25 In other words, our relationships with our plant food comrades, even those that have been with us for a long time, require a lot of work to maintain on good terms.
The great irony about plant foods is that the more we reduce their harmful by-products and chemical defenses, the more sugarlike they become, and thus the more we increase our risk of acquiring chronic diseases like type 2 diabetes and gout. The ultimate reason for this double-edged character of plant foods is that they are not our original food source; we don’t have the specialized digestive systems or teeth that dedicated herbivores like gorillas and cows possess to grind and digest large quantities of unprocessed plant foods, and must make do with a series of ingenious culinary workarounds to render plant foods suitable eating.
But such ingenuity! The staples that we grow up with become enshrined in our hearts, and the plant that has been arguably closest to Westerners’ hearts for several millennia has been wheat. In the Lord’s Prayer, Christians recite: “Give us this day our daily bread.” Wild wheat was gathered at least as far back as 17,000 BC. The great virtue of wheat is that it contains starch, an easily digestible carbohydrate, and gluten protein, which is sticky and can be leavened with yeast to make bread (rice lacks gluten and therefore makes poor bread); as mentioned, the process of fermenting wheat and turning it into bread reduces harmful oxalate levels.26
However, wheat—and gluten in particular—has become the scorn of a rising movement, blamed for instigating a plethora of diseases. Celiac disease is an autoimmune intestinal disorder triggered by the form of gluten protein found in wheat, barley, rye, and closely related cereals; it currently affects 1 to 2 percent of people in Western countries. The symptoms of celiac disease usually take months or years to develop after exposure to gluten. Children with celiac disease may eventually exhibit anorexia, lack of energy, pale skin, growth retardation, delayed puberty, or rickets, while adults with celiac disease may experience symptoms including diarrhea, nausea, vomiting, stomach pain, flatulence, and weight loss.27 Celiac disease is also prevalent in North Africa, India, and the Middle East. Wheat, barley, and rye have been major food sources for thousands of years in the areas where celiac disease is most common, so why has natural selection not curtailed the frequency of the genes underlying celiac disease?28
One possibility is that the cereals that trigger celiac disease have not been consumed by us for a long enough time for evolution to do its work. According to this argument, the three hundred or so human generations that have been exposed to these cereals were not affected enough by celiac disease for it to have diminished the ability of these people to bear children. The problem with this argument is that celiac disease is a serious disorder and would have harmed a person’s reproductive prospects in the days before medical treatment and glutenfree diets were widely available.
An alternative argument is that the genes that promote celiac disease may somehow give people better health in other ways. When scientists scanned gene databases for patterns in celiac disease, they found that some of the genes that lead to celiac disease increased in frequency between 1,200 and 1,700 years ago, just when human dependence on cereals should have pushed the genes to obscurity. The key is that these same genes are also involved in protecting people against bacterial infections. In other words, celiac disease may be a double-edged disorder, which confers bacterial protection but makes bearers of these genes vulnerable to gluten poisoning.29
However, celiac disease is increasing rapidly, and not everyone who has a genetic predisposition toward celiac disease develops it.30 Changing genes cannot be a complete explanation. Something crucial in the environment must have altered as well. Scientists have recently observed that birth via Cesarean section may increase the risk of celiac disease, perhaps due to the lack of transmission of the mother’s intestinal bacteria to the baby; overuse of antibiotics may similarly reduce intestinal bacteria and increase the risk of celiac disease.31
Other disorders besides celiac disease have been blamed on the consumption of wheat. For example, wheat allergies have become more prominent (the topic of food allergies will be discussed in a later chapter). Other gluten reactions seem to involve neither autoimmune (as in celiac disease) nor allergic mechanisms and are currently lumped under the label “nonceliac gluten sensitivity,” or more often “gluten sensitivity.” Commonly reported symptoms of gluten sensitivity include headaches, “foggy” states of mind, fatigue, depression, bone or joint pain, muscle cramps, leg numbness, and weight loss. People with gluten sensitivity believe that the symptoms improve when gluten is removed from the diet, but many medical practitioners and doctors are skeptical because clinical experiments have not demonstrated any symptoms from gluten consumption so far. The link with gluten may be a nocebo (i.e., negative placebo) effect, purely in the mind. The perceived problems with eating wheat products may stem from other chemical components that are present alongside gluten; for example, there has been a surge of interest in the study of short-chain sugars (also known as FODMAPs, for fermentable oligo-, di-, and monosaccharides and polyols) that ferment quickly in the intestines, causing bloating, gas, gastroesophageal reflux, and diarrhea, and may be the true cause of gluten sensitivity. FODMAPs are extremely widespread in contemporary Western diets, in the following chemical forms and foods:
• free fructose in apples, cherries, mangos, pears, watermelons, asparagus, artichokes, sugar snap peas, honey, and high-fructose corn syrup
• lactose in milk, yogurt, ice cream, custard, and soft cheeses
• fructans (fructose chains) in peaches, persimmons, watermelons, artichokes, beetroot, Brussels sprouts, garlic, leeks, onions, peas, wheat, rye, barley, pistachios, legumes (beans), lentils, and chickpeas
• galacto-oligosaccharides (short chains of galactose sugars) in legumes, chickpeas, and lentils
• polyols (sugar alcohols) in apples, apricots, pears, avocados, blackberries, cherries, nectarines, plums, prunes, cauliflower, mushrooms, and snow peas32
Intestinal discomfort may therefore result not simply from eating too much wheat (or gluten) but rather from eating too many sugary foods, including factory-made sweetened breads as well as fruits and fructose-containing foods. Like celiac disease, FODMAPs may lead to intestinal discomfort when intestinal bacteria populations are altered through the overuse of antibiotics. Another consideration is that moderate exercise can help to reduce gastrointestinal disorders such as irritable bowel syndrome and constipation, whereas too much vigorous exercise can exacerbate gastrointestinal disorders like reflux, heartburn, diarrhea, and gastrointestinal bleeding.33 Overall, plant foods are best prepared and eaten in traditional ways—grated, steamed, roasted, fermented, and so on—rather than served raw, and complemented by a lot of moderate exercise like walking and the avoidance of particularly sugary foods, which will help alleviate intestinal discomfort from FODMAPS-induced gas.
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When I first arrive in China, I eagerly try the street food in the student ghettos surrounding Bengbu College, but the fare—wheat wraps, vermicelli soups, barbecue skewers—is disappointingly oily and spicy. I know there must be better food out there, but the students generally can’t afford to eat off campus, and I don’t speak enough Mandarin to befriend the teachers who can’t speak English. As a result, I spend most of my evenings at the track, trying to jog while weaving around chatting students and families, or at the gym, playing basketball, badminton, table tennis, and volleyball with students and teachers. After Christmas, the English Department desperately needs volleyball players to help trounce the Nutrition Department, the latest incarnation of the annual teachers’ competition. Although I am technically a member of the International Relations Department, I had played setter and captain on my high school’s junior volleyball team, so through bureaucratic sleight of hand, I become a bona fide member of the English Department. It’s going to be a big match, I’m told over and over by jittery colleagues. The day of the big game, I get psyched and participate in a super-vigorous warm-up session. Unfortunately, I have been experimenting with low-glycemic diets of barley, oats, millet, beans, and other indigestible food and warm up so hard and have been out of volleyball for such a long time that I am famished and exhausted by the time the game starts. As the students crowd the sidelines and yell out coordinated cheers, I fan at the ball a few times and botch some easy sets. We squander the big match. My colleagues are crushed. However, I am told there will be another set of games the next day, a chance for possible redemption.
Before heading to the match the following afternoon, I pull out a frozen banana from the freezer and microwave it to a steaming calorie-rich mush and pop an obsidian-black “thousand-year” cured and salted duck egg in my mouth. I bound to the gym like a 150-pound Vietnamese version of the Incredible Hulk. The English Department students have mostly given up on us and gone home for the long-weekend holiday, but I pound the ball and scream as if it’s an Olympic showdown. After losing our first match, we win our second match against the Biology Department, salvaging pride and second place overall. The English Department has secured its reputation for another year.
I am invited to a celebratory banquet at a fancy restaurant in Bengbu. Cigarettes are passed around, hard liquor poured out. This evening is about slapping backs, shaking hands, pouring drinks for senior colleagues, making toasts—all the schmoozing needed to smooth out office politics for the upcoming months. I am toasted for my efforts on the volleyball court, but my attention is riveted by the platters of food being slowly spun around the table: honeyed slices of lotus, crispy fried carp, tender marinated beef quivering with fat, savory pork ribs, a mob of other delicacies, every dish a winner. My salary at the college is $800 a month, of which $400 is siphoned off to service my student loans, which makes me poor even by Chinese standards. I’ll never see the likes of this food again. I’m feted with rice wine until my head can barely stay level, but like a man just rescued from weeks of being stranded in the desert, I continue to obsessively pick at the remnants of the dishes while the teachers fervently schmooze.
