perinatal flavor exposure
process / process-perinatal-flavor-exposure
周産期風味曝露
Infant exposure to flavor through amniotic fluid during pregnancy or breast milk during nursing.
On this page (5 sections)
Reading the bitterness
Perinatal flavor exposure refers to the idea that flavors from foods eaten by the mother reach an infant through amniotic fluid during pregnancy or breast milk during nursing and affect later acceptance of tastes. A 2001 study of 47 mother–infant pairs compared groups given 300 mL of carrot juice on 4 days a week for 3 weeks, either late in pregnancy or during the first 2 months of nursing, with a water control group. Infants exposed to carrot flavor prenatally (paired t(14) = 2.88, P = .01) or through breast milk (paired t(16) = 2.41, P = .03) showed fewer negative facial expressions toward carrot-flavored cereal than toward plain cereal. The unexposed control group did not show this difference.
However, this finding cannot be extended directly to bitterness. The paper does not characterize carrot as a bitter food, and group-by-flavor interactions were not significant for cereal intake (F(2,43) = 1.09, P = .34) or eating time (F(2,43) = 0.88, P = .42). The effect was shown in facial expressions and the mothers' own ratings, not in a change in the amount actually eaten. Extending it to acceptance of bitter foods is an inference beyond the paper.
A longitudinal study also explicitly compared the presence or absence of bitterness. It gave fetuses at 32 and 36 weeks of pregnancy a single flavor stimulus of kale (bitter) or carrot (non-bitter), followed by repeated consumption from 36 weeks until birth, and followed facial responses at 3 weeks after birth and through age 3. Across all measurement points, kale flavor tended to elicit significantly more negative facial expressions (cry-face gestalt) than carrot (p<0.001). The fetal assignments were 14 for kale and 20 for carrot, and only 12 participants remained through the age-3 follow-up.
A separate analysis of the same cohort at age 3 presented both kale and carrot odors to children whose mothers had repeatedly consumed kale late in pregnancy. Within the same children, negative expressions were significantly fewer for the odor to which they had been repeatedly exposed prenatally than for the unexposed odor (p<0.001). This was a within-person comparison; the authors interpreted it as evidence that fetal chemosensory memory persists for years after birth. Only 12 participants were followed through age 3.
Sources for this overview
Prenatal and postnatal flavor learning by human infants
Checked for this overview: Checked the numerical results for fewer negative facial expressions in the exposure groups. / Checked the nonsignificant interactions and that extension to bitterness is an inference.
Checked for this overview: Checked differing rates of negative expressions for bitter kale and non-bitter carrot. / Checked reduced negative expressions for the exposed odor in a within-participant comparison at age 3.
Structured claims — open a section to read each claim's confidence, evidence and limits
Sensory (3)
Scope: Randomized 3-group design, 47 mother-infant pairs who completed the study. During the last trimester of pregnancy or the first 2 months of breastfeeding, 300 mL of carrot juice 4 days a week for 3 weeks (Mennella 2001)
Note: The target is carrot flavor, not bitterness (no mention of bitter in the text). The group × flavor interaction for intake and feeding duration was not significant. Positioned as contextual material connecting to the acquired-taste line as a foundation for flavor learning in general.
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process-perinatal-flavor-exposure —increases→ "Infant acceptance of an exposed flavor during weaning: groups exposed either prenatally or postnatally showed fewer negative facial expressions to carrot-flavored cereal than to plain cereal"Scope: Stratum: food. A single flavor-capsule stimulus (kale or carrot) to the fetus at 32 and 36 weeks of pregnancy, repeated intake from week 36 to delivery, and longitudinal follow-up through 3 weeks and 3 years after birth (the number of codable data points varies by measurement point; final follow-up n=12).
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process-perinatal-flavor-exposure —increases→ "Across multiple measurement points from the fetal period (32 and 36 weeks of pregnancy) through after birth (3 weeks and 3 years), the bitter kale-flavored stimulus tended to elicit significantly more negative facial expressions (cry-face gestalt) than the non-bitter carrot-flavored stimulus (p<0.001)."Scope: Stratum: food. Repeated intake of kale- or carrot-flavored capsules in late pregnancy (from week 36 to delivery); an olfactory presentation test with a within-subject comparison presenting both odors at age 3 (n=12).
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process-perinatal-flavor-exposure —reduces→ "When kale and carrot odors were presented at age 3 to 12 children of mothers who had repeatedly consumed kale (bitter) flavor in late pregnancy, within the same children, negative facial expressions to the odor of the flavor they had been repeatedly exposed to prenatally were significantly fewer than negative facial expressions to the odor of the flavor they had not been exposed to (p<0.001). The authors interpret this as evidence that fetal chemosensory memory persists for years after birth."