The Flavoring of Amniotic Fluid and Breastmilk by Maternal Diet
by Anne Eglash MD, IBCLC, FABM
It is common knowledge that certain flavors from mother’s diet transfer into breastmilk. In fact, some flavors, such as alcohol, garlic, and vanilla, show up in the breastmilk within hours of a single maternal ingestion of the flavor.
The question is how does this influence infant feeding choices? In a previous Clinical Question of the Week from the Dutch Generation R Study, there was no significant difference in picky eating behavior among 4 year olds who were never-breastfed vs those exclusively breastfed for 6 months.
The systematic review for this week’s question was initiated as part of the United States Department of Agriculture and the US Department of Health and Human Services Pregnancy and Birth to 24 Months Project. The role of maternal diet in promoting healthy eating during early childhood was considered a high priority topic. The systematic review included 11 articles assessing the diet of women during pregnancy, and 15 articles on the diet of women during lactation. In both sets of literature, the reviewers evaluated the transfer of flavor to amniotic fluid or breastmilk, and children’s behavioral response to the flavor.
- Maternal intake of garlic, alcohol, and anise during pregnancy resulted in significantly higher acceptance of these flavors (via odor) by infants when re-exposed to these odors from 3 hours-14 days after birth, as compared to infants whose mothers did not ingest these flavors during pregnancy.
- 8-9 year old children have been shown to consume more garlic if their mothers at garlic during the last 4 weeks of pregnancy.
- Vanilla in the mother’s diet has been shown to be associated with an increase in milk intake by the breastfeeding infant.
- Infants whose mothers drank vegetable juices for 1 month, starting at 2 weeks postpartum, ate more carrot flavored cereal at 6 months compared to those infants whose mothers didn’t drink vegetable juice.
- Flavors of fish have not been shown to be detectable in breastmilk.
See the Answer
Maternal diet during pregnancy and lactation may provide the earliest opportunity to positively influence child food acceptance.
Systematic reviews were completed to examine the relation among maternal diet during pregnancy and lactation, amniotic fluid flavor, breast-milk flavor, and children’s food acceptability and overall dietary intake.
A literature search was conducted in 10 databases (e.g., PubMed, Embase, Cochrane, and CINAHL) to identify articles published from January 1980 to June 2017. Data from each included study were extracted, risk of bias assessed, evidence synthesized qualitatively, conclusion statements developed, and strength of the evidence graded.
Eleven and 15 articles met a priori criteria for inclusion to answer questions related to maternal diet during pregnancy and lactation, respectively.
Limited but consistent evidence indicates that flavors (alcohol, anise, carrot, garlic) originating from the maternal diet during pregnancy can transfer to and flavor amniotic fluid, and fetal flavor exposure increases acceptance of similarly flavored foods when re-exposed during infancy and potentially childhood. Moderate evidence indicates that flavors originating from the maternal diet during lactation (alcohol, anise/caraway, carrot, eucalyptus, garlic, mint) transmit to and flavor breast milk in a time-dependent manner. Moderate evidence indicates that infants can detect diet-transmitted flavors in breast milk within hours of a single maternal ingestion (alcohol, garlic, vanilla, carrot), within days after repeated maternal ingestion (garlic, carrot juice), and within 1–4 mo postpartum after repeated maternal ingestion (variety of vegetables including carrot) during lactation. Findings may not generalize to all foods and beverages. Conclusions cannot be drawn to describe the relationship between mothers’ diet during either pregnancy or lactation and children’s overall dietary intake.
The authors conclude that there is no research evaluating the relationship between maternal diet during lactation and toddler dietary intake. Based on what I see in my clinical practice, I would say they are unlikely to be related. One finding in this systematic review is that infants had a greater preference for some flavors in their solids when exposed to them in breastmilk regularly in the first few months of life (carrot juice), rather than if they were exposed at 4-6 months. This would go along with the typical eating behavior of toddlers, who love a food for a certain while, then refuse to eat it for several months. Even infants become tired of the same flavor when given it too often. Yet it seems that early frequent exposure to the flavor encourages an acceptance later in infancy. For this reason, the authors comment that the relationship between exposure of flavors during pregnancy and postpartum via breastmilk may be more about timing of exposure to the flavors rather than the frequency or intensity of the exposure.