by Wilson, Bee
Instead, in many countries, formula milk has been flavored, if at all, with vanillin, the artificial vanilla flavor that goes into industrially produced sweet foods, from ice cream to biscuits to cake. Vanilla milk has a long history. Back in 1940, the head nurse of the children’s hospital in Philadelphia recommended tempting reluctant feeders with three drops of vanilla essence in each bottle. Internet forums suggest that there are still many desperate parents who resort to vanilla extract when a baby rejects the bottle.
Since 1981, international food standards (the Codex Alimentarius of the World Health Organization) have stated that no flavorings should be added to infant formulas aimed at newborns. But vanillin is still a key ingredient in many of the “toddler milks” marketed for children aged one and over. In China, vanillin is prohibited in infant formula, but it continues to be illegally added by many manufacturers. In 2014, a team of chemical analysts found vanillin in four out of twenty samples of infant formula randomly purchased from supermarkets in the city of Wenzhou.
Of all the flavors you could think of with which to “imprint” a child, vanilla is possibly the least useful from a health standpoint (except, perhaps, chocolate: in 2010, the American company Mead Johnson withdrew its “premium” chocolate-flavored Enfagrow toddler milk amid complaints from leading nutritional scientist Marion Nestle that it was training kids to “like candy”). The effects of vanilla milk are lasting. In 1999, some researchers in Germany tested the effects of the vanilla that had been in German “bottle milk” during the postwar years. The scientists asked 133 people to try two different ketchups, one of which was straight-up tomato ketchup and one of which, bizarrely, had been flavored with vanillin. (The reason the researchers chose ketchup was precisely that it is not normally associated with vanilla.) Of the respondents, the majority of those who had been breastfed had a preference for the pure ketchup, while the majority of those who had been reared on vanilla formula preferred the strange vanilla ketchup. Their baby milk had brainwashed these unfortunate people into thinking that vanilla made everything taste better.
Clearly, spinach milk would be a better plan, assuming it could be made safe for tiny infants. It will probably never take off, though. Over time, the odds are that babies would accept it and even prefer it, just as the hydrolysate babies with their bad-tasting formula think that milk is meant to taste sourish and cheesy. It’s the parents who would find vegetable milk hard to accept. We want our babies to have milk that corresponds to our own memories of childhood. Manufacturers know that you can only sell baby food by making it appealing to adults, which is why baby rusks are sometimes sweeter than doughnuts and why, for decades, until it was banned, jars of baby mush came seasoned with monosodium glutamate (MSG), to give it a more savory taste. When vanilla is found in baby foods, it has been put there to attract not the children themselves—who, as we’ve seen, can become emotionally bonded to flavors that are strange, sour, or strong, given the right memories—but to please adults. The babies are not the ones who buy the food. It is the grown-ups’ memories that the food companies are trying to appeal to. As they warm the sterilized bottle, parents sniff their baby’s milk; or maybe take a tiny sip. It is they, not the babies, who have memories of how childhood milk ought to taste: creamy and sweet, like milk left behind in the cereal bowl.
Do you remember your first passion fruit, your first avocado, your first Thai green curry? Such flavor memories can seem inconsequential, the stuff of gastronomes. “Ah, yes, it was in Marseille in 1987 that I first tasted an authentic bouillabaisse.”
Yet, from the perspective of neuroscience, food memories are not something slight. Registering different flavors is one of the main ways that our bodies interact with the world around us. Amazingly enough, the human olfactory bulb is the only part of the central nervous system that is directly exposed to our environment, through the nasal cavity. Our other senses—sight, sound, and touch—need to travel on a complicated journey via nerves along the spinal cord up to the brain. Smell and flavor, by contrast, surge directly from plate to nose to brain.
Conventional wisdom used to be that humans have rather a weak sense of smell, compared to that of other animals: dogs, say (witness the fact that we don’t have sniffer humans at airports). But recent research suggests the contrary. We may not have a bloodhound’s ability to track a scent, but our olfactory discernment is second to none. We can detect a drop of Worcestershire sauce in a glass of tomato juice, or the scent of fear in another person’s sweat.
When I say that we discern smells and flavors, what I should really say is that we create them. Flavor is not actually in food, any more than redness is in a rose or yellow is in the sun. It is a fabrication of our brains, and for each taste, we create a mental “flavor image,” in the same way that we develop a memory bank of the faces of people we know. The difference is that whereas faces fade when you haven’t seen them in a while, flavors and smells have a way of lodging themselves indelibly. What you taste as a child is still there in your adult brain, even if you haven’t thought of it for years. The Norwegian Trygg Engen, the “founding father” of the study of smell and memory, characterized our sense of smell as “a system designed not to forget.”
In 1991, the biologists Richard Axel and Linda Buck discovered that olfactory receptors—cells in the nose that detect odor molecules—make up the largest single family in the human genome. Out of around 19,000 genes, Axel and Buck found, nearly 1,000—5 percent—are olfactory receptors. Their research finally unlocked some of the mystery of how humans can remember and discriminate among so many flavors and smells (and, thirteen years later, won them a Nobel Prize).
What makes the human system of olfaction so sophisticated is not just the receptors themselves, but the way they interact with our large brains. Each receptor cell is fairly specialized: it can detect only a small number of substances. But when you smell or taste something—a loaf of freshly baked bread, or lemon zest sprinkled over a stew—the receptors send messages to the olfactory bulb in the brain. Here, each flavor becomes encoded in its own particular pattern in a part of the olfactory bulb called glomeruli. A glomerulus has been described as a “detection point par excellence.” Each and every time you taste or smell something, the relevant glomerulus will take a snapshot of it. These snapshots show up in the brain as patterns, like a map.
Humans can distinguish around 10,000 separate smells, estimates Linda Buck. We walk in the house and instantly know that someone is cooking roast chicken for supper, and that they decided to stuff it with rosemary instead of thyme. Our olfactory systems have an immense power to detect flavors. Molecules that look nearly identical, to a specialist chemist in a lab, will be easily distinguished by an ordinary person who smells them. Our brains will also interpret the same chemical in radically different ways depending on how concentrated it is. Buck and colleagues note that a “striking example is a substance called thioterpineol, whose odor is described as ‘tropical fruit’ at a low concentration, as ‘grapefruit’ at a higher concentration, and as ‘stench’ at a still higher concentration.”
Once we move beyond smell to consider flavor, however, the images processed in our brains become vastly more complex. In addition to the odor signals from our noses—this coffee is good!—there will be taste signals from the mouth—oh, but it’s bitter!—as well as feelings of texture—smooth cream!—and temperature—that burned my tongue! The experience of tasting food is far more multisensory than is the case with hearing, sight, or touch, which is why it requires the most sophisticated part of our brains to process it. In fact, eating is influenced by hearing, sight, and touch as well as flavor: we prefer apples that crunch loudly, steaks that look blood-red, sauces so smooth they seem to caress the inside of our throats.
If there are 10,000 smells, the number of different flavors that our brains can potentially create is infinite. Professor Gordon M. Shepherd, a biologist based at Yale University, has coined the term “neurogastronom
y” to explain our brain’s unique flavor system. In Shepherd’s view, complex flavor recognition is at the core of human identity, separating us from other mammals. Cats cannot even detect something as basic as sugar—they lack a taste receptor for sweetness. Humans, on the other hand, can differentiate fake maple syrup from real maple syrup, Coke from Diet Coke. Shepherd notes that the images of different flavors humans build up are processed in the prefrontal cortex, the area of the brain that is most important not only for decision making and abstract thought, but also for memory. Shepherd’s work has shown that the human brain can potentially generate any number of flavors, “since every soluble body has a special flavor which does not wholly resemble any other.”
The way our brains interpret flavors speaks to the human love of patterns. Professor Shepherd and colleagues have done experiments using fMRI and other brain-scanning technologies to show that different flavors register as different patterns in the brain. It is startling to see scans of these flavor maps and realize that there is a separate place in our brains for bananas and cheddar cheese, or that strawberries and sugar show up as dots in similar locations. The way our brains map flavor is similar to the way we perceive visual images. When we “see” something, what we are actually doing is creating an abstract 2D representation of it, with some features enhanced and others suppressed. By the same token, when we put food in our mouths, the flavor molecules that drift to our noses are turned into abstract patterns in the brain. These patterns help us to recognize the food when we taste it again. Our olfactory receptors give different patterns to the sweet and the savory, the rotten and the fresh. The receptors also modify the patterns depending on what is happening in the rest of the body: whether we are happy or depressed or nauseous.
Through these patterns, our brains make sense of the bewildering world of flavor. Take umami, the so-called fifth taste, which corresponds to the savory qualities in meat, cheese, and certain vegetables, such as tomatoes or broccoli. Umami is what gives mushrooms their oomph and the reason it’s so hard to stop pouring gravy on your potatoes. We all have neurons that are specifically tuned to umami. Yet, by itself, umami—which is made in artificial form as MSG—doesn’t really taste of much. It is only in conjunction with other flavors that it becomes delicious. We can see this from neuroimaging studies. When glutamates are tasted in conjunction with a savory vegetable flavor, they generate far more brain activity than when the two flavors are tasted separately. The whole is more than the sum of its parts. This makes sense. Our brains are smart enough to see that a dish of Asian greens with soy sauce warrants a more sizable flavor image than the same greens and soy sauce eaten separately.
What is most significant about our flavor images is the way they lead to what scientists call “images of desire.” Once we have a memory in our heads of a flavor we love, we build up “images of desire” as we seek to acquire it again. In 2004, researchers put subjects on a bland diet and asked them to imagine their favorite foods. Just thinking about these beloved dishes created a response signal in the hippocampus, insula, and caudate—the same areas of the brain that are activated during drug craving. Canadian researchers found that people who described themselves as “chocolate cravers” showed different brain activity when eating chocolate than self-diagnosed non-cravers. The cravers’ brains continued to respond favorably to pictures of chocolate long after their bodies had reached a point of fullness. Neuroscience confirms that chocolate means more to some people than to others.
To anticipate pleasure in the next meal—something that can take up the greater part of the day, in my experience—is always a form of memory. And each mouthful recalls other mouthfuls you’ve eaten in the past. It stands to reason, therefore, that the flavor patterns in our brains are highly dependent on all the things we’ve tasted in the past, especially during childhood. Among North Africans who settled in France, fresh mint tea, often served in ornate teapots, is a way of life. Children grow up with that familiar herbal steam rising from the table as adults sit and talk. A particularly refreshing mint tea is served in the courtyard of the Great Mosque of Paris, a tranquil place to retreat on sweltering days in the city.
For French Algerians, mint tea is imprinted on the mind in a way that doesn’t hold true for the non-African French population. In 2009, a group of subjects, half of them “Algerian French” and half of them “European French,” were asked to smell mint and say what they thought of it. All of them—French or Algerian—found it pleasant, and all of them correctly identified it as mint. But when gold electrodes were attached to the scalp, the Algerians showed a significantly greater level of neural activity in response to the mint than the Europeans. Because of the mint tea they drank at home, the smell induced a different cortical pattern in the brain. Put simply, mint was a flavor that resonated more with Algerians than with non-Algerians. This was an image their brains had already recognized many times before. If mint were a sound instead of a taste, you could say that the French heard the notes, but only the Algerians appreciated the music of it. Because their memories of it were more expansive, mint actually took up more of their brain.
When we are unable to obtain the flavors we remember from childhood, it can give rise to longings so intense it is hard to think of anything else. The anosmia sufferers we met at the start of the chapter, such as Marlena Spieler, would confirm this: she hankers for the flavors that would make her feel “like Marlena” again.
Some of the most poignant examples of this flavor-yearning are the food obsessions of prisoners of war. When Primo Levi was imprisoned in a work camp near Auschwitz called Buna, he remembered that fellow prisoners not only groaned in their sleep, but licked their lips: “They are dreaming of eating; this is also a collective dream. . . . [Y]ou not only see the food, you feel it in your hands, distinct and concrete, you are aware of its rich and striking smell.”
Among memoirs by World War II prisoners of war, a common theme is not just hunger, but the fevered memories to which it gave rise, consisting of all the things the POWs would eat again once they were free. Very seldom did they build these dreams about the grown-up foods of sophisticated restaurants; it was the food of childhood and of home that came to mind: stodgy, filling, and safe. One British ex-POW remembered dreaming two nights in a row about “omelettes and treacle pudding.” He also remembered his bitter disappointment on waking up, since “either was as obtainable as a slice of the moon.”
Food obsession reached a particularly feverish pitch among European, American, and Australian POWs in the Far East, where the mismatch between their rations of rice and the food they longed for was enough to make them slightly unhinged. Food historian Sue Shephard writes that most of the men in the Japanese camps “regressed to a childish state.” They all hallucinated about sugar: for the British it might be chocolate éclairs, suet puddings, and steaming bowls of buttercup-yellow custard; for the Americans, Hershey bars, mother’s apple pie, and every kind of layer cake, from devil’s food to coconut. Some men refused to join in the collective discussions of food because it was too painful to be reminded of how far they were from home, but for most of them, the crazy food talk became a survival mechanism to get through the endless days of boredom and brutality. One long-term POW recalled that after the first year and a half or so, the food talk had completely supplanted daydreams about women.
Some men went so far as to write down elaborate menus and even recipes on scraps of paper. Filmmaker Jan Thompson, who spent twenty years interviewing former American POWs for her 2012 documentary Never the Same, found that a common theme was writing down Thanksgiving menus, reconstructed from “memories of childhood gatherings.” All memory is a distortion, and in their half-starved state, these men constructed holiday menus more lavish than any of them can have actually enjoyed as a child. In Japan, Mess Sergeant Morris Lewis felt oppressed by the responsibility of looking after his soldiers as well as himself. Sergeant Lewis kept himself “sane” by writing down an extraordinary
Thanksgiving dinner menu that included Virginia Baked Ham, fried rabbit, cranberry sauce, Snowflake Potatoes, candied sweet potatoes, buttered sweet corn, buttered asparagus tip, and green stuffed olives. Then, “Assorted Cookies,” “Assorted Nuts,” “Assorted Candies,” “Assorted Ice Cream”; also “Ass. Jams” and “Fresh Ass. Fruit & Grapes.”
This word “assorted” is heartrending, coming from a man whose diet had been reduced to abject monotony. Prison can famously expand the imagination. After all this time without cookies, nuts, candies, or ice cream in any form, Sergeant Lewis was planning a meal where all of these treats were freely offered in multiple varieties. He had returned to that old childhood pipedream of being given free rein in a candy store.
POW yearnings for childhood foods were like an exaggerated version of the food nostalgia we all feel. The thing you are seeking to recover is not just the flavor in itself, but all the things that went with it: your family sitting round the table, the feeling of being cared for, the freedom from responsibility. This is why it’s possible to long for bad food, too, just because of the happy connotations it may have. Not everyone grows up with a mother who turns out perfect apple pies. POW Russell Braddon, a “cheeky young Australian gunner” who spent three years in Japanese camps, was thrilled to get a card from his sister. It arrived sixteen months after she first posted it, and it had to be short because the limit was twenty-five words:
Dear Russ, Mum’s puddings are still as lumpy as ever. Oodles of love from us all. Pat.
Braddon later said that this letter told him “all I wanted to know”: that his family did not accept he was dead, and that “the old household jokes about my mother’s rather abandoned cooking still flourished.”