【正文】 n, the fetusamp。 taste buds are fully developed, and its olfactory receptors, which allow it to smell, are functioning. the flavors of the food a pregnant woman eats find their way into the amniotic fluid, which is continuously swallowed by the fetus. babies seem to remember and prefer these tastes once theyamp。re out in the world. in one experiment, a group of pregnant women was asked to drink a lot of carrot juice during their third trimester of pregnancy, while another group of pregnant women drank only water. six months later, the womenamp。s infants were offered cereal mixed with carrot juice, and their facial expressions were observed while they ate it. the offspring of the carrot juice drinking women ate more carrotflavored cereal, and from the looks of it, they seemed to enjoy it more.
　　a sort of french version of this experiment was carried out in dijon, france where researchers found that mothers who consumed food and drink flavored with licoriceflavored anise during pregnancy showed a preference for anise on their first day of life, and again, when they were tested later, on their fourth day of life. babies whose mothers did not eat anise during pregnancy showed a reaction that translated roughly as amp。yuck.amp。 what this means is that fetuses are effectively being taught by their mothers about what is safe and good to eat. fetuses are also being taught about the particular culture that theyamp。ll be joining through one of cultureamp。s most powerful expressions, which is food. theyamp。re being introduced to the characteristic flavors and spices of their cultureamp。s cuisine even before birth.
　　now it turns out that fetuses are learning even bigger lessons. but before i get to that, i want to address something that you may be wondering about. the notion of fetal learning may conjure up for you attempts to enrich the fetus like playing mozart through headphones placed on a pregnant belly. but actually, the ninemonthlong process of molding and shaping that goes on in the womb is a lot more visceral and consequential than that. much of what a pregnant woman encounters in her daily life the air she breathes, the food and drink she consumes, the chemicals sheamp。s exposed to, even the emotions she feels are shared in some fashion with her fetus. they make up a mix of influences as individual and idiosyncratic as the woman herself. the fetus incorporates these offerings into its own body, makes them part of its flesh and blood. and often it does something more. it treats these maternal contributions as information, as what i like to call biological postcards from the world outside.
　　so what a fetus is learning about in utero is not mozartamp。s amp。magic fluteamp。 but answers to questions much more critical to its survival. will it be born into a world of abundance or scarcity? will it be safe and protected, or will it face constant dangers and threats? will it live a long, fruitful life or a short, harried one? the pregnant womanamp。s diet and stress level in particular provide important clues to prevailing conditions like a finger lifted to the wind. the resulting tuning and tweaking of a fetusamp。 brain and other organs are part of what give us humans our enormous flexibility, our ability to thrive in a huge variety of environments, from the country to the city, from the tundra to the desert.
　　to conclude, i want to tell you two stories about how mothers teach their children about the world even before theyamp。re born. in the autumn of 1944, the darkest days of world war ii, german troops blockaded western holland, turning away all shipments of food. the opening of the naziamp。s siege was followed by one of the harshest winters in decades so cold the water in the canals froze solid. soon food became scarce, with many dutch surviving on just 500 calories a day a quarter of what they consumed before the war. as weeks of deprivation stretched into months, some resorted to eating tulip bulbs. by the beginning of may, the nationamp。s carefully rationed food reserve was pletely exhausted. the specter of mass starvation loomed. and then on may 5th, 1945, the siege came to a sudden end when holland was liberated by the allies.
　　the amp。hunger winter,amp。 as it came to be known, killed some 10,000 people and weakened thousands more. but there was another population that was affected the 40,000 fetuses in utero during the siege. some of the effects of malnutrition during pregnancy were immediately apparent in higher rates of stillbirths, birth defects, low birth weights and infant mortality. but others wouldnamp。t be discovered for many years. decades after the amp。hunger winter,amp。 researchers documented that people whose mothers were pregnant during the siege have more obesity, more diabetes and more heart disease in later life than individuals who were gestated under normal conditions. these individualsamp。 prenatal experience of starvation seems to have changed their bodies in myriad ways. they have higher blood pressure, poorer cholesterol profiles and reduced glucose tolerance a precursor of diabetes.
　　why would undernutrition in the womb result in disease later? one explanation is that fetuses are making the best of a bad situation. when food is scarce, they divert nutrients towards the really critical organ, the brain, and away from other organs like the heart and liver. this keeps the fetus alive in the shortterm, but the bill es due later on in life when those other organs, deprived early on, bee more susceptible to disease.
　　but that may not be all thatamp。s going on. it seems that fetuses are taking cues from the intrauterine environment and tailoring their physiology accordingly. theyamp。re preparing themselves for the kind of world they will encounter on the other side of the womb. the fetus adjusts its metabolism and other physiological processes in anticipation of the environment that awaits it. and the basis of the fetusamp。 prediction is what its mother eats. the meals a pregnant woman consumes constitut