Flavors in breast milk? From the food that mothers ingest? Yes, it really happens, and babies can taste the difference. It might even affect their food preferences later in life.
A mother eats a spicy meal, then nurses her baby an hour later. Will the flavors make their way into the breast milk? Will her baby detect undercurrents of garlic? Top notes of ginger and coconut?
The baby probably isn’t mulling it over with the vocabulary of a foodie. But the basic notion isn’t far-fetched. A mother’s diet really can affect the taste of her milk, and babies don’t just notice these flavors. They also respond to them. Here’s how we know.
More garlic-flavored breast milk, please.
What happens if you ask a bunch of breastfeeding mothers to swallow some garlic pills? Researchers tried it, and confirmed through lab analyses that the garlic made its way into the women’s milk. The flavor peaked between 1.5 to 3 hours after ingestion, at which point the women were asked to feed their 3-month-old babies. And then?
Compared with babies whose mothers had swallowed placebo pills, the “garlic babies” spent more time feeding. They apparently liked the garlic (Mennella and Beauchamp 1991).
A similar experiment suggests that babies enjoy vanilla, too (Mennella and Beauchamp 1996). And when researchers asked lactating women to ingest four different flavor capsules, they found that all four flavors — banana, caraway, anise, and menthol — could be detected in breast milk later on. Banana peaked after just one hour, but the others lasted longer (Hausner et al 2008).
So it seems likely that many food flavors make their way into breast milk. Does this have any lasting effects?
Do babies remember flavors in breast milk, and recognize these flavors when they start eating solid foods?
Julie Mennella and colleagues wanted to find out, so they recruited a group breastfeeding women, and then randomly assigned some of the mothers to drink carrot juice each day for the first 2 months postpartum. Months later, when the babies were 5-6 months old, the researchers brought the babies into the lab for a taste test. On different days, the babies were offered plain cereal and carrot-flavored cereal. What happened next?
All the babies made screwy, disapproving faces when they encountered the carrot-flavored cereal. But compared with babies in a control group, the babies who had been exposed to “carroty” breast milk reacted less negatively (Mennella et al 2001). They seemed to recognize the taste of carrots — more than three months after their mothers had stopped drinking carrot juice.
Menella’s lab obtained similar results in a later study, one in which mothers were instructed to drink four different types of vegetable juice (vegetable, beet, celery, and carrot) for one month during the early weeks postpartum. Later, when the babies were 8 months old, they took the carrot taste test, and — once again — infants in the experimental groups (whose mothers had consumed vegetable juices) showed less negativity in response to carrots (Menella et al 2017).
Does this mean that any amount of exposure to flavors in breast milk will make babies like a given food?
Not necessarily. In the first study, the carrot-exposed babies didn’t eat more carrot-flavored cereal. They just showed fewer negative reactions to the taste. In the second study, the researchers found possible evidence for increased liking, but only for infants whose mothers had consumed vegetable juices from 2 weeks postpartum to 6 weeks postpartum (Menella et al 2017).
And consider what happens if babies are offered something other than carrots. When researchers at the University of Coperhagen tested the effects of caraway exposure on 5-8 month old breastfeeding babies, they found that 10 days of exposure to carroway flavors in breast milk had no impact on the babies’ acceptance of a carroway-flavored purée (Hausner et al 2010).
So the research doesn’t tell us that exposure to flavors in breast milk will make babies like a particular food. But it does support a more fundamental idea — that babies begin learning about food flavors long before they start eating solid foods.
That shouldn’t surprise us, not if we consider the evidence for prenatal learning about food. Babies develop the ability to taste and smell before they are born, and food flavors can pass through the placenta and into the amniotic fluid (Spahn et al 2019). Studies indicate that newborns are more accepting of flavors they have encountered during gestation. Read more about the fascinating research in my article, opens in a new window“Prenatal learning: Do “pregnancy foods” affect babies’ eating habits?”
Does breastfeeding help shape childhood eating habits?
The caraway study didn’t support a short-term exposure effect, but researchers did notice an interesting difference between breastfed and formula-fed babies: Regardless of whether or not their mothers had consumed carroway, breastfed babies showed a higher initial acceptance of the carroway purée than formula-fed infants did (Hausner et al 2010).
That’s consistent with other research showing that breastfed infants are more likely to accept new foods, and more likely to have varied diets as they get older. For instance, research suggests that infants are less likely to become picky eaters later in life (Forestell 2017). And the longer babies breastfeed, the more likely they are to consume vegetables during early childhood (de Wild et al 2018).
Could this be because the experience of tasting many different foods — experiencing many different flavors in breast milk — prepares babies to sample a variety of solid foods? If so, this could be an important benefit of breastfeeding (Spahn et al 2019; Ventura et al 2021).
In support of the idea, a study tracking the development of more than 1500 children (from infancy to 6 years) found intriguing links between breastfeeding, maternal diet, and child outcomes. The more vegetables that a mother ate at around the 3 months postpartum — and the longer she breastfed her baby — the more likely it was that her child would end up with a diet high in vegetables (Beckman et al 2020).
In particular, among kids who had been breastfed for at least 16 weeks total, each additional serving of vegetables in their mothers’ breastfeeding diets was linked with 22% increased odds of eating a diet high in vegetables at age 6. And this was true even after the researchers made statistical adjustments for the effects of socioeconomic status, the timing of the introduction of solid vegetable foods, and a variety of health-related variables (Beckman et al 2020).
What about babies on formula? Do they have any interesting flavor experiences?
Formula might never taste like garlic or carrots, but different formulas have somewhat different flavors, and these, too, may influence the development of food preferences.
In an experiment on preschoolers, Djin Gie Liem and Julie Mennella asked kids to taste a variety of juices, each characterized by different levels of sweetness and sourness. The researchers found that kids who’d consumed sour-tasting, protein hydrolysate formulas as babies preferred higher concentrations of citric acid in their juice (Liem and Mennella 2002). Kids who’d used a different formula were less likely to enjoy sour juice.
A similar study found that kids who had consumed soy-based formulas were more likely to enjoy a bitter-tasting juice (Mennella and Beauchamp 2002).
And other experiments suggest that babies fed hydrolysate formulas are less likely than babies on milk-based formulas to consume pureed broccoli or cauliflower (Mennella et al 2006)
So it appears that a child’s food preferences aren’t purely idiosyncratic or arbitrary. They aren’t just a reflection of individual genetics, or media hype, or even childhood experiences. They are influenced by prenatal events and encounters during infancy — exposure to flavors in breast milk and formula (Forestell 2017).
What else is in breast milk? Read about the nutrients in breast milk opens in a new windowhere.
References: Flavors in breast milk and formula
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Content of “Flavors in breast milk” last modified 2022
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Portions of the text appeared in previous, older versions of this article by the same author.