Imagine your toddler willingly eating every healthy food that you offer. Bunches of broccoli, stacks of spinach, loads of lima beans … all consumed without a fight. The notion that any child has a natural inclination toward healthy foods might seem far-fetched, but some scientists suspect that there's a very important window of opportunity for a mother to instill good eating habits in her children. Research is underway to determine how a woman's diet during pregnancy might influence her offspring's food preferences later in life. What they're discovering is encouraging.
Teeny, Tiny Taste Buds
Nine weeks after conception (during pregnancy week 12), an unborn baby develops its first taste buds. Connections between the taste buds and the brain—which makes perceiving flavor in food possible—aren't made until a little later in the fetus's development. Scientists are unsure how functional these first taste buds may be, but they do know that unborn babies can swallow. In adults, taste buds make it possible to differentiate between salty, sweet, bitter, and sour tastes. Yet most scientists believe that taste buds account for only a small percentage of what most people think of as flavor: your ability to detect the subtleties in a certain food and enjoy it.
The Nose Knows
The real story lies in what an unborn baby may be smelling due to what the mother is eating. Flavor begins with the nose. "'Flavor' is a term that is used by the lay public," explains Dr. Richard Costanzo, PhD, professor of physiology and otolaryngology/head and neck surgery at the Virginia Commonwealth University. He says that scientists' definition of flavor is different; they think of it as a complex arrangement between mouth, nose, and brain working in concert to enjoy a certain food. And when it comes to "figuring out" the flavor, it's the nose that does most of the work, not the taste buds.
A simple test will give you an idea of how important smell is in determining the flavor in food. The next time you're eating something—an apple, a cookie, or even a latte—plug your nose. What's the flavor? You may be able to tell what the food is by the texture or the temperature, but you won't be sensing much in terms of flavor. Nasal pathways must be open so that small cells within the nose, called olfactory receptors, can pick up on odors and pass the information on to the brain.
A New World of Smells
As an unborn baby develops, nose plugs block the nasal passages until four to six months after conception. Once the nose plugs fall away, the fetus can take in the amniotic fluid and "smell." According to Dr. Gary K. Beauchamp, PhD, director of the Monell Chemical Senses Center in Philadelphia, "Odors are dissolved in amniotic fluid and this bathes the olfactory receptors." Like the air we breathe, amniotic fluid is constantly circulating through the nose of the fetus, immersing it in a world of smells.
While an unborn baby obviously can't decipher what the smells are, it does become accustomed to certain odors. Researchers in France found that newborns later recall smells from the womb. Three-day-old babies were offered two pads—one saturated with amniotic fluid collected from their own mothers, and the other from another baby's amniotic fluid. The behavior of the newborns indicated that they preferred the familiar scent. Moreover, scientists have observed that familiar odors have a soothing and relaxing effect on the babies. After all, babies first identify their mothers by smell.