First Bite: How We Learn to Eat. Bee Wilson

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СКАЧАТЬ Even babies have nostalgia! It’s a large part of how we learn to eat. The foods parents give to babies provide them with powerful memories that trigger lasting responses to certain flavours. This process begins before birth. We are all born with echoes of our mother’s diet, which mean that no one is a totally blank slate when it comes to flavour. We arrive predisposed to respond to certain foods by our experiences in utero.

      It’s hard to know what a newborn thinks about taste, since we can’t exactly ask them. Or rather, they can’t exactly answer. But in 1974 the Israeli doctor Jacob Steiner realized that a baby’s reactions to the basic tastes of sweet, sour, salty, bitter could be gauged by their facial expressions, which are vivid and mobile, even in the first week.¹¹ Steiner took babies just a few hours old and offered them a range of tastes on a cotton swab, filming their facial expressions. When given salt, which you’d think might make them cry, the babies surprisingly showed little reaction, continuing to look expressionless (a liking for salt only emerges later, around four months). But all the other basic mouth-tastes produced strong reactions. The sour swab made the babies pucker their lips. Bitterness provoked an expression of abject distress and an open mouth, as if trying to spit or vomit it out. As for the sweet swab, Steiner found that it produced a dreamy look of ‘relaxation’ with an ‘eager licking of the upper lip’ and even a ‘slight smile’ – and this at an age when babies are not supposed to be capable of smiling. Such is the power of sugar.

      The test has since been repeated many times, with similar results. What it confirms is that, as we have seen, all human babies, from Sweden to China, have a strong innate preference for sweetness and a dislike of bitterness and sourness. Basic tastes are not a question of memory: we are hard-wired to think sweetness is wonderful and that bitterness is scary. No one has to learn these simple tongue-reactions. But flavour is another matter. Flavours – these memories generated backwards through our nose – are all learned. What we think about flavour in all its myriad forms, from toasted cumin to sea bass, from parsley to spaghetti carbonara, is not fixed. Each of us will have a different bank of memories and feelings about these; and it exists from day one, if not before.

      Taste buds appear at seven or eight weeks of gestation. Already, by thirteen to fifteen weeks, the taste buds are mature. A thirteen-week-old foetus weighs maybe an ounce, with no fat under the skin, no air in the lungs. Yet already they can not only swallow but taste, and these sips of fluid leave memories.

      In 2000 some French scientists did a remarkable experiment showing that newborns arrive in the world with a memory of how their particular amniotic fluid tasted.¹² The mothers studied came from the Alsace region where strong-tasting anise sweets are a local delicacy. Some of the women had eaten anise regularly during pregnancy and some had not. The babies were tested straight after birth and four days later, having tasted nothing outside the womb but milk. When an anise odour was wafted in front of them, the babies born to anise eaters showed a marked and ‘stable’ preference for anise. They turned their heads towards the anise smell, sticking their tongues out with a licking gesture. They remembered it and apparently it pleased them.

      Further experiments have confirmed that other strong flavours such as garlic can also find their way into amniotic fluid. In one study, women agreed to swallow garlic capsules forty-five minutes before they were due for an amniocentesis; when it was tested, their amniotic fluid smelled garlicky.¹³ Babies born to voracious garlic eaters will have been floating in a sac of garlic water for nine months. It has been shown that babies exposed to garlic before birth are more likely to enjoy garlic in food later on. Likewise, mice whose mothers had been fed on artificial sweeteners when pregnant had an exaggerated taste for sweetness.¹⁴ Pregnant rats fed on junk food – including savoury snacks, sweetened cereals and chocolate-hazelnut spread – had babies who also selected these foods over regular rodent pellets, though the babies’ preference for junk was lessened if the mothers switched to a healthier diet during lactation.¹⁵

      The flavours our mothers ingest most regularly can become like mother’s milk to us. Julie Mennella and Gary Beauchamp are biopsychologists working at the Monell Chemical Senses Center in Philadelphia who have done a series of experiments on how flavour in utero and in breast milk leaves children with lasting memories and preferences for certain foods.¹⁶ One of their most celebrated studies, from 2001, involved carrot juice. The babies of a group of mothers who drank carrot juice during the last trimester of pregnancy and again during the first two months of breastfeeding were predisposed to like the flavour of carrot. When the babies were weaned onto solid food, several months after the mothers stopped drinking the carrot juice, they showed a marked preference for cereal flavoured with carrot juice over plain cereal flavoured with water.

      The early exposure of babies to flavour – both in utero and through milk – works as a kind of ‘imprinting’, as Gary Beauchamp puts it.¹⁷ We become emotionally attached to these early aromas. As we saw in Chapter One with the ‘flavour window’, younger babies are more open than older ones to new tastes. When it comes to weaning, this is an argument for ignoring the advice on exclusive breastfeeding for six months and offering early, varied bites of vegetable purées between four and six months. When it comes to the pre-food stage, however, flavour may be one of the strongest arguments for mothers attempting to breastfeed, at least for the first few months, to eat as varied a diet as possible while doing so. Some psychologists suggest that instead of saying to mothers: ‘breastfeed for the baby’s good’ healthcare advisers should say: ‘breastfeed for your own good’ because you are likely to have a baby who is less fussy to deal with in the early stages of eating.¹⁸ Then again, I’ve known children (not my own) who’ve gone from formula milk at four months to black olives and spinach tart at twelve months, so it doesn’t always follow.

      It is curious that we talk so little about the flavour of formula, given that it is the main food many babies taste for that crucial first year. Because any given brand of formula milk does not vary, it seems to have an even greater ‘imprinting’ power than breast milk. Babies who cannot tolerate regular cow’s milk formula are sometimes given special ‘hydrolysate’ formula, whose proteins have been broken down (hydrolysed) to make them more digestible. To adult tastes, these formulas taste especially nasty, with a sour cheesy tang and a strange hay-like odour. Mennella and Beauchamp followed children who had been fed with two different hydrolysate formulas.¹⁹ Objectively, both of these milks tasted equally unpleasant. But to the infants, the particular formula they had been assigned – sour or not – taught them how food should taste. When the two brands were switched round, the infants drank less: they preferred their own bad-tasting formula to the other one. More strikingly still, children aged four to five who had been fed on these sour-tasting hydrolysates as babies showed more positive feelings about sour tastes and smells than children who had been fed on breast milk or regular formula. This is vivid proof that anything can start to taste good if you have enough positive memories of being fed it by a parent. The obvious implication is that formula-fed babies would benefit from having their milk flavoured with vegetables.

      Formula can never match the myriad benefits of breast milk, which range from lessening the risk of eczema and ear infections to reducing the likelihood of type 2 diabetes later in life to promoting healthy gut microbiota. But in the developed world, as we’ve seen, most mothers are unable or unwilling to breastfeed exclusively for the first six months. With each of my own babies, I gave it up for one reason or another (illness, work, bereavement and a child with feeding difficulties) at three months. Until they were a year old, when they were old enough for regular whole cow’s milk, I’d have been glad to buy formula that was mildly scented with a range of green vegetables, just enough to give them a memory of spinach when the time came for them to try veg for real.

      Instead, in many countries, formula milk has been flavoured, if at all, with vanillin, the artificial vanilla flavour 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.²⁰ СКАЧАТЬ