Weanling Infants Prefer the Odors of Green Vegetables, Cheese, and Fish When Their Mothers Consumed These Foods During Pregnancy and/or Lactation

Abstract

Infants' olfactory experience begins before birth and extends after birth through milk and complementary foods. Until now, studies on the effects of chemosensory experience in utero and/or through human milk focused on experimentally controlled exposure to only 1 target food bearing a specific odor quality and administered in sizeable amounts. This study aimed to assess whether early olfactory experience effect was measurable in "everyday conditions" of maternal food intake during pregnancy and lactation, and of infant intake at weaning, leading to expose the infant to corresponding odors as fetus, neonate, and infant up to 8 and 12 months of age. Infants' early food exposures were assessed by asking mothers to fill out diaries about their food consumption during pregnancy and breastfeeding, and about their infant's consumption during complementary feeding. To test odor liking, odorants representing a priori pleasant and unpleasant food odors, as well as odorless stimuli, were presented. The infant's exploratory behavior toward odorized bottles and nonodorized control bottles was measured in terms of mouthing duration, which is thought to reflect attraction and/or appetence. At age 8 months only, positive correlations were found between liking of some unpleasant odors and early exposure to these odors through mother's diet. No correlations were found between infants' liking of the pleasant odors and early exposures to the foods bearing these odors. This study highlights that early exposure to unpleasant food odors may increase subsequent liking (or reduce subsequent dislike) of these food odors at least until the age of 8 months.

Keywords: amniotic fluid; breast milk; complementary feeding; liking; olfaction; perinatal exposure.