We decided to investigate whether scientific evidence supports the belief that a woman’s diet during pregnancy significantly influences the taste preferences of her future child.
Let’s agree to use official terminology throughout the text. We will refer to the organism from conception up to the ninth week of intrauterine development as an embryo or a germ, from the ninth week until birth as a fetus, and from birth as a child or a baby.
The embryo forms its first sensations through touch. According to Heidi Murkoff, the author of “What to Expect When You’re Expecting” and a popular science writer, sensory receptors develop on the face of the embryo, primarily around the lips and nose, at around eight weeks of age. At approximately 18 weeks, the fetus begins to hear both internal sounds such as the mother’s heartbeat and external sounds. Taste receptors also form during the embryonic period and are connected to the neurons responsible for transmitting taste sensations by the eighth week of pregnancy. However, the embryo cannot yet discern taste, as taste buds, which develop only at the 15th week, are necessary for their recognition. The first taste the fetus experiences is slightly salty amniotic fluid, which it swallows. The fetus swallows between 200 to 500 mg of amniotic fluid per day, and in the last weeks of gestation, it can consume up to a liter of fluid per day. Even though the mother’s digestive system is separate from the fetus’s digestive system, individual food components that the mother consumes can enter the amniotic fluid. However, the way that the fetus experiences food is different from what we are used to because the aroma, which is a crucial component of any dish, is not present.
In 2001, the Monell Chemical Senses Center in Philadelphia, an independent scientific institute, published one of the earliest studies on the relationship between a mother’s diet during pregnancy and the taste preferences of newborns in the journal “Pediatrics.” The study involved 46 women in their third trimester of pregnancy who planned to breastfeed after childbirth, and they were randomly divided into three groups. The first group consumed 300 ml of carrot juice four times a week for three weeks during pregnancy and avoided carrots and carrot juice while breastfeeding. The second group was instructed to avoid carrots and carrot juice during pregnancy but was given 300 ml of carrot juice every day for two months while breastfeeding. The third group abstained from consuming carrots and carrot juice during the last trimester of pregnancy and while breastfeeding. The article detailing the study results did not provide information on the participants’ dietary habits before the experiment.
At five and a half months old, the infants’ taste preferences were evaluated by researchers. None of the infants had consumed carrot juice or any food containing carrots previously. The experimenters offered the infants cereal flakes that were diluted with either water or carrot juice. The researchers based their conclusions on external observations of the infants during feeding, such as whether they turned away from the food, spit it out, or cried. The majority of the infants whose mothers drank carrot juice during pregnancy or lactation showed a preference for the flakes with carrot juice. Conversely, the group of infants whose mothers abstained from carrot juice exhibited predominantly negative reactions.
The scientists concluded that the infants’ familiarity with the taste of carrot juice contributed to their preference for it. While this approach may help ease the introduction of complementary feeding and the transition to solid foods, the researchers did not investigate how these children would perceive carrots in subsequent years. In a 2016 article, researchers from the same Monell Chemical Senses Center highlighted that a diet rich in fruits and vegetables during pregnancy also influenced the infant’s preference for such a diet. The experts see an evolutionary component to this phenomenon: the fetus “remembers” the most common and safe foods that the mother consumed during pregnancy and passes on this preference to the child.
A 2019 systematic review of published studies found that fetuses could remember not only the taste of vegetables and fruits but also recognize spices like garlic or anise after birth. The review also included retrospective studies that showed that children whose mothers consumed alcohol during pregnancy could remember and recognize its smell well after birth. However, despite an extensive search of scientific publications in the PubMed and Google Scholar databases, no studies were found on whether it is possible to cultivate a preference for food groups like meat and meat products, fish and seafood, cereals and grains, eggs, dairy products, bread and pasta, nuts, and mushrooms in utero.
Researchers have attempted to establish a correlation between a mother’s healthy diet during pregnancy and her child’s food preferences. Observations of women and their children ranged from nine months to four years. Children whose mothers had a healthy diet during pregnancy – including fruits and vegetables, fish, dairy products, and greater variety – also preferred this style of eating over sweetened drinks and pastries. However, extrapolating these findings to a child’s lifelong diet is difficult, as the observations were limited to a specific period. For example, a mother may have adopted healthy eating habits during pregnancy, provided a relatively healthy diet for her child, but then returned to unhealthy eating habits after giving birth, which could “retrain” the child’s preferences.
Mothers who consumed a lot of processed foods, sweetened drinks, semi-prepared meals, and refined carbohydrates during pregnancy increased the likelihood of their children gaining excess weight in adolescence compared to their peers. Additionally, consuming “junk” food (foods high in fat and/or sugar but low in fiber, protein, vitamins, and minerals) during pregnancy altered the reward system in the offspring’s brain, as demonstrated by an animal experiment. The researchers fed pregnant rats unhealthy human food such as nut butter, peanut oil, chocolate bars, chips, sweetened flakes, and fatty fast food. The offspring of these rats had a less sensitive reward system to unhealthy food, requiring more sugar and fat to reach the same level of dopamine as the offspring of rats whose mothers followed a typical rat diet.
During the prenatal period, programming of the future child’s taste preferences is indeed possible. However, it’s crucial to note that all known studies, both on humans and animals, have assumed regular consumption of certain foods, rather than occasional consumption. In other words, consuming neither a box of donuts nor a whole container of ice cream once during pregnancy will program the child to exclusively eat unhealthy food. Similarly, a single serving of broccoli or carrots will not turn a baby into a fan of healthy food. Additionally, studies have mainly focused on the preferences of infants and toddlers, and taste preferences can significantly change by adolescence. Therefore, it’s essential to follow the principles of proper nutrition throughout pregnancy and ideally throughout life, avoiding excessive consumption of processed meats, fast food, and sweetened beverages.
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