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Is picky eating simply in poor taste? by Perri Klass

taste.there’s no accounting for

You taste with your tongue, but your “taste” also applies to your other sens-es, to what you like to look at and listen to. There’s no analogous way to refer to your “ear” for food, or your “nose” for music. When it comes to representing preference and even prejudice, we use the sense of taste to embody opinion.

And you can convince yourself to gaze at a painting that is outside your usual pref-erences, you can listen with anthropological curiosity to your adolescent children’s idea of good music—but you can’t chew your way through something you truly dis-like with a smile on your face. Taste, when it’s really taste-with-your-tongue, is more profound and more, well, visceral than that.

It comes up a great deal in primary care pediatrics because so many children are picky eaters, and because picky eaters drive their parents crazy. There are so many

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the sen

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ways of being a picky eater, and all of them, I would venture to guess, are more or less heartfelt. That is, children are not doing this to jerk their parents around. Oh, they’re jerking their parents around all right, but that’s not the why. I have noticed that often when I ask graduate students to write personal essays, many of them write about a food aversion going back to childhood. No one understood, no one believed, but they hated chocolate, or fruit, or something considered a delicacy. The more limited their tastes, the more clearly they remem-ber being misunderstood, being pushed to try what they knew they didn’t like, being forced into the same defensive con-versation over and over.

Pediatricians take it as our business to direct parents on how to start solid foods. And to be honest, that concept—start solid foods—is firmly embedded in a particular moment and in a particular culture. What we tell parents now is a little bit different from what we told them even twenty years ago, though it follows certain basic lines, yes, start sol-ids in the middle of the child’s first year of life (ideally around six months), start one new food at a time. We used to advise avoiding eggs and citrus for the first year; now we don’t. But mostly we all believe that you start by offering children bland and mushy foods and you work your way slowly toward color, texture, anything that’s sharp or spicy or bitter or umami-ish.

But not all children have read the playbook. Some grab barbecued spareribs off a parent’s plate (that was my daughter), or beg for spoon-fuls of the hot spicy soup before they have any words, or lick the deli mustard off a parent’s pastrami sandwich. And other children reject anything and everything, according to their own mysterious neuronal code: nothing too hot or too cold, nothing green, nothing with real texture. You name the exclusion, and someone in the room has a pre-school child who follows that rule as if it had come down from Mount Sinai (speaking of famous food prohibitions).

Some of the more familiar you know: there are the children who do not eat anything green. I have a friend whose nine-year-old will send back a pile of French fries (his favorite food, and at certain times in his life, his only reliable food) if the restaurant, in an upscale excess of enthusiasm, has sprinkled them with tiny bits of fresh parsley. And then there are those who don’t do spicy—though, to be honest, many adults don’t do spicy. And there are entire cultures, of course, where everyone—children and adults—cheerfully does spicy.

And then there is the infamous “white diet.” I think of this as pret-ty much the ultimate picky eater state, more extreme than the anti-

greens. These kids eat white bread, they eat noodles (sometimes with melted butter), they eat chicken fingers and French fries (if you don’t sprinkle them with parsley or paprika or some other evil substance) and of course, they occasionally indulge in vanilla ice cream. But the re-ally interesting thing about the white diet is that each child invents it

anew, cutting his teeth, so to speak, on rice cereal, and moving on from there to other varieties of—let’s face it—pap, whether served hot or cold, loose in a bowl or fried in strips. The true white diet child makes no exception for ketchup either (how loud, how red, how tasty!)

Picky eaters require special meals, force their parents to carry supplies along to restaurants and birthday parties, and en-gender a certain moral righteousness. The world is full of people who will look at your picky eater and assume it’s all your fault. You didn’t set limits, did you? You acceded to his request and made him special dishes, didn’t you?

A pediatrician friend told me a story about two mothers whose children she cares for—the mothers are sisters, and one has a white-diet child. The mother comes in and talks to the pediatrician about how restricted her child’s diet is, how worried she is that her child is falling off the growth curve, what a pain it is that wherever she

goes, she has to bring along a little container of one of this child’s few foods, so that the child will consume a couple of calories. The mother’s sister then complains to the same pediatrician about how offended she is that her sister always brings food when she comes to visit, which she takes as a comment on her cooking abilities.

“What I say to people in the office is just keep putting stuff on the table that you want her to eat—if he doesn’t eat it, he’ll have a bowl of cereal before he goes to bed, he’ll make some mac and cheese,” my friend said.

We speculated about whether picky eaters are more common than they used to be: would our mothers have put up with this? Would our grandmothers? I remember two categories of children from when I was young: “he’s a good eater” and “she eats like a bird.” Presumably the eats-like-a-bird kids were the picky eaters.

I have watched parents struggle, sometimes over the course of years, with children who do not like most of the things that delight the rest of us. In extreme cases, I have worried about the child’s growth and the child’s health and the child’s hematocrit; much of the time, I have just worried about the daily dinnertime struggles, the tension that de-velops between parent and child, and the complications of personal preference and family life. And I have felt sad sometimes for children

children are not doing this to jerk their parents around. Oh, they’re jerking their parents around alright, but that’s not why.

mmm. That first sip of coffee in the

morning. The taste of butter on sourdough toast, perhaps with a dab of raspberry jam. [replace with more evocative foods?] Such flavors can make a person’s day—unless they arise unbidden, without the company of food or drink. For about 7 percent of patients with psychotic disorders such as schizophrenia, gustatory hallucinations—phantom tastes that arrive suddenly and fade just as quickly—are a common and disturbing part of life.

Moreover, most phantom tastes aren’t delicious, according to Kathryn Lewandowski, an

HMS instructor in psychology at McLean Hospital, who evaluated psychotic patients to assess the type and range of hallucinations they experience as part of a large, ongoing study. Rather, the tastes are unpleasant and confusing.

“Often patients experience a generically unpleasant taste,” Lewandowski says. “Some people do experience the taste of specific foods. But usually patients can’t identify the taste; it’s just generally disagreeable.”

Clinicians have traditionally associated gustatory hallucinations—along with hallucinations of smell and touch—with brain tumors and lesions rather than with

idiopathic psychotic disorders. As a result, they often overlook such phenomena. With her study suggesting that gustatory hallucinations are also associated with certain types of delusions and an earlier onset of psychosis, a possible marker of more severe illness, Lewandowski recommends that clinicians ask patients whether they have experienced such sensations.

“Patients don’t always report them freely,” Lewandowski says. “To fail to ask about them misses information that may be clinically relevant in terms of diagnosis but also just in terms of understanding patient experience and identifying

THE PHANTOM GOURMET

for some patients with psychotic disorders, mysterious tastes are part of daily life. by Elizabeth Dougherty

Breath by ChocolateYour mother told you not to inhale your food, but if you want to indulge in the pleasures of chocolate without the attendant calories, you may just want to take a whiff. David Edwards, a member of the Wyss Institute for Biologically Inspired Engi-neering at Harvard, has created a mini-inhaler—dubbed Le Whif—that shoots a chocolate mist into one’s mouth, mimick-ing, he says, the experience of savoring the real thing.

Edwards is known in sci-ence circles for designing a more efficient way to deliver inhaled medicines by tinkering with the particle sizes, and he has tapped that science in his lipstick-sized chocolate delivery gadget. The chocolate particles are small enough to shoot out of the brightly colored inhaler, but too large to make it to the lungs.

Not only does this delivery system remove the guilt that comes with chocolate’s calo-ries, he says, but it also moves us toward our culinary future. Evolution, he says, is trending toward smaller meals eaten more frequently—until chew-ing is pretty much replaced by breathing. “Breathing is eat-ing,” he says.

Of course, before dessert comes the main meal; Edwards has plans for inventing inhal-able steak, carrots, and more. But for now, he is busy market-ing Le Whif; a world tour is on tap. “The whole process is very

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t he proof is in the pudding. In The Luck of the Loch Ness Monster, picky eater

Katerina-Elizabeth dumps her oatmeal over the side of an oceanliner each morning, and each morning, a sea worm gobbles it up, becoming larger and larger until he grows into the Loch Ness Monster.

“Oatmeal is like slug slime, only lumpier,” says Alice Flaherty ’94, the author of the children’s book and a mostly unreformed picky eater. “My parents would boil Scottish steel-cut oatmeal for 45 minutes before we could eat it, and while it was boiling it would belch big oatmeal bubbles of steam into the air.”

When she was little, Flaherty’s father told a version of the monster story to get her to eat her oatmeal. “Although I loved the story, it didn’t make me eat,” she says. “Now I have twin girls, one of whom is a picky eater like me, the other a normal eater like my husband. That got me interested in the biology of pickiness.”

People often blame picky eating on children’s willfulness,

Flaherty says. Much pickiness is genetic, though, and sometimes even helps children stay healthy. Most picky eaters have a “supertaster” gene. If you have both copies of the gene, you taste flavors strongly, especially bitter compounds in foods like broccoli. If you have neither copy, you can’t taste those bitter flavors at all.

Whether you’re a non-taster or a supertaster or somewhere in-between depends on your sensitivity to a bitter chemical called 6-n-propylthiouracil, or PROP. Non-tasters—about one-quarter of the population—cannot detect the bitterness of PROP at all. Medium tasters—half the population—can sense the bitterness but don’t mind it, while supertasters—the final quarter of the population—find the taste of PROP revolting.

Children taste PROP more strongly than adults and, unlike adults, they always seem to sense the bitterness of the chemical. So it could be that certain flavours taste different to children than they do to most adults. This might explain why they’re

SUPERTASTER SCIENCE genetics play a huge role in fussy eating habits. by Alice Flaherty

Taste the BurnThere’s a certain kind of magic in Thai food. The fire hits hard, then it fades. The taste buds beg for another bite. This enchanting cycle of fleeting and repeating self-torture and sweet relief continues, until—the bowl of Tom Yum soup drained, the last grains of rice devoured—you take your next shot at a peppery, lemongrassy adventure.

The ancients who crafted these exotic herbal concoc-tions, it turns out, were culi-nary alchemists, pairing their seasonings to agonize—and to entice. Little did they know that centuries later scientists would still be working to tease apart the secrets of their sa-vory mastery.

Chemicals called tastants cause the burning sensation and subsequent cooling relief so common in Asian cooking. Capsacin, a chemical in pep-pers, triggers sensations of heat and pain by stimulating taste receptors on the tongue. Citral, a chemical in lemon-grass, squelches that heat.

Fans of hot, spicy food know that a sip of water amplifies

the peppery burn by helping the capsacin get onto [bet-ter verb] the taste receptors. Milk dampens the burn as its fatty lipids sweep some of the compound away.

“Citral makes it not so hot, but in a different way,” says Stephanie Stotz, a research fellow in cardiology at Chil-dren’s Hospital Boston who described her findings in a May 2008 PLoS ONE article.

Stotz found that citral blocks G protein-coupled receptors—transient receptor potential ion channels in taste buds—only after they have been activated and depolar-ized by, say, a tastant such as capsaicin. Stotz showed that citral blocks these open taste detectors in model cells.

But the way citral blocks these receptors has a temporal component: it allows a quick surge of taste response—the burn—then dampens it for an extended time—the cooling relief.

The molecular mechanisms governing the prolonged cool-ing effect of compounds such as citral remain a mystery. Yet unraveling these mecha-

m odern synthetic chemists

know better than to wave a pipette or gloved finger near their mouths. But in 1879, by and large, curiosity trumped safety.

Case in point: Johns Hopkins chemists Constantin Fahlberg and Ira Remsen discovered saccharine in an accidental tasting. The reports vary, but only in the details—according to a 1927 article in Science, Remsen transferred the compound from lab to hand to dinner roll to mouth; according to an 1895 blurb in the New York Times, Fahlberg’s taste traveled from pencil tip to tongue. The serendipitous discovery led to four patents and went on to sweeten the once-popular soda called Tab,

among other things.But how, exactly, did

Fahlberg (or was it Remsen?) physiologically detect that sweet taste? Until 2001, the cellular receptors involved in triggering the brain to detect a sweet sensation on the tongue were unknown. In fact, none of the cellular receptors for sweet taste was known until researchers—including a team led by Linda Buck, then an HMS professor—discovered them in 2001.

Today, scientists have identified the taste receptor genes for four of the five tastes: Bitter, sweet, sour, and umami, or savoriness. The cells that make up taste buds on the tongue express these genes to create receptors that detect the molecular tastants, depolarize the cells, and trigger a signal to

the brain. What remains to be

understood is the one flavor that makes everything taste better, from cookies to grilled steak to butter: salt. “Candidate salty receptors have been proposed, but it is not clear that these are in fact the key mediators of salt taste,” says Stephen Liberles, an HMS assistant professor of cell biology who worked with Buck on the taste receptor work. [continue quote]

Understanding these taste receptors [specifically for salt? or taste receptors in general?], the windows into our enjoyment of the best foods and our rejection of the vile, could help researchers develop safer tools than fingers and pencil tips for taste-testing new compounds.

A PINCH OF SALTthe receptors for the key flavor that makes everything taste better remains elusive to scientists. by Elizabeth Dougherty

Menu MattersYou study a restaurant menu and decide to order the steak rather than the salmon. But when the waiter tells you about the lobster special, you decide lobster trumps steak. Without reconsidering the salmon, you place your order—all because of a trait called “transitivity.”

Transitivity underlies rational economic choice, according to work done in the laboratory of HMS Professor of Neurobiol-ogy John Assad. According to transitivity, if you prefer lobster to steak, and steak to salmon, then you will prefer lobster to salmon.

In the brain, transitivity is wired by neurons in the orbi-tofrontal cortex. They encode economic value in what HMS researchers call a “menu-invari-ant” way. That is, the neurons respond the same to steak regardless of whether it’s of-fered against salmon or lobster. “The activity of these neurons does not vary with the menu op-tions,” says first author Camillo Padoa-Schioppa, a former HMS postdoctoral fellow.

“This study provides a key insight into the biology of our frontal lobes and the neural circuits that underlie decision making,” Assad adds. “We can, in fact, compare apples to or-anges, and we do it all the time. Camillo’s research sheds light on how we make these types of choices.”

Scientists have linked “choice deficits”—such as eating dis-orders, compulsive gambling,