A woman will be bombarded by a list of rules as soon as a couple announces the impending birth of their child.
Don’t eat soft cheeses or cold meats. Avoid salads and unwashed vegetables. Yeah, right.
The flavour of food is a question that has always fascinated me. As a mother and her developing fetus have such a close relationship, it is intriguing to ask if the food choices made by a pregnant woman can affect what their child will like to eat once they are born.
What science is there?
Strange-smelling newborns
Hospital reports of babies born with distinct smells were the first scientific indication that certain elements in a mother’s food may affect a developing baby.
An Israeli team published a series of cases studies. They described four babies with a distinctive smell that was reminiscent of food the mother had eaten just before giving birth.
Two mothers from this case study had babies with a cumin-like smell. The mothers admitted to the researchers, after a short quiz, that they both had eaten Middle-Eastern “schug” in the days before delivery. This is a hot sauce made with cumin, garlic, and other ingredients. A newborn baby of another woman was smelling strongly of fenugreek. This is a leguminous, sweet-nutty plant that has seeds. A similar questioning revealed that the mother consumed a large amount of “high,” a Yemenite dish made from fenugreek, shortly before giving birth.
These case studies provide the first evidence that this old wives’ tale could be true. The mother’s eating habits may affect her child for a lifetime.
Next, we will explore the biological mechanisms that may be involved.
Amniotic fluid flavouring
Our stomach and intestines break down food and drinks into small molecules, which are then absorbed by the bloodstream. The placenta, umbilical cord, and even molecules that produce an odor in the mother can pass to the fetus’ bloodstream during pregnancy.
The fetus is enclosed in a membrane called the amniotic sac, which contains a mucous fluid. The amniotic liquid is filled with mucous-like fluid (amniotic) that the developing baby can urinate in. This means that a portion of odorous molecules from the mother’s placenta or umbilical cord will be transferred to the child and end up there. It is not surprising that a fetus who has been bathed in an amniotic sac for 40 weeks would have a little pong.
Julie Mennella from the United States and her colleagues were the first to show experimentally how a woman’s dietary habits can affect the odor in the amniotic liquid. Researchers identified ten women about to undergo routine amniocentesis. Amniocentesis involves the removal of a small amount of amniotic liquid from the amniotic sac using a large needle for medical testing. The women were all in their second trimester.
Five women were given a garlic capsule 45 minutes prior to their amniocentesis. The other five women received a milk capsule. Researchers then assembled an “odour-panel” of 13 adults who were given samples of amniotic liquid from two women: one who had consumed a capsule of garlic and another who had taken a capsule of milk. The panel did not know which sample came from which woman. Their job was to decide which sample smelled more like garlic.
The results were unambiguous. The judging panel almost unanimously chose samples of amniotic liquid from women who had eaten garlic capsules to smell more garlic. Garlic extract taken by the women before the amniocentesis gave their amniotic liquid a garlic-like smell.
It is important to know that the amniotic liquid can be “flavored” because, by the second quarter of pregnancy, a fetus will be able to ingest amniotic. Near-term fetuses can consume up to 1000ml of fluid a day. This is approximately 50% of the fluid volume in the amniotic sac. This swallowing helps to regulate the liquid level in the amniotic pouch and can also help with the development of a baby’s digestive system and respiratory systems.
Can babies develop a taste for certain flavors by consuming flavored amniotic liquid in the womb?
Test your sense of smell.
Our sense of smell is just as important to our taste perception as our senses of taste.
This means that the odorous molecules of the amniotic liquid can reach the olfactory receptors (smell) in the nose. Is it possible that infants exposed to these “smells” in utero are more attracted to them after birth?
A French research team examined this idea. The preference of two groups of pregnant women for the flavor of aniseed was used to select them. Twelve women from the first group were regular consumers of aniseed-flavored foods and drinks. In comparison, twelve women in the second group had never eaten or drunk anything with this flavor. The first group was given aniseed cookies, lollipops, and beverages in the last two weeks of their pregnancy to ensure that they consumed enough of the flavor.
Two cotton-tipped swabs were held under the noses of the newborns, one after another, immediately after their birth. The researchers dipped one swab in an aniseed syrup and the other in paraffin. Researchers then recorded how newborn babies responded to different tastes.
Infants who had mothers who consumed aniseed regularly during pregnancy spent more “mouthing” time (mouth opening, suction, and tongue protrusions) toward the aniseed swab. The paraffin swab was also more disliked by the infants than the aniseed one. The infants of mothers who did not consume aniseed while pregnant spent the same amount of time mouthing each of the swabs. This indicates that they had no preference.
