You Are What Your Parents Eat: Parental Influences on Early Flavor Preference Development

Author(s):
Catherine A. Forestell

Children consume fewer fruits and vegetables than recommended, and their diets are high in saturated fat, sugar, and salt. For example, in the USA, more than 25% of infants and toddlers do not consume a single serving of fruit or vegetables on any given day [1]. Children’s preference for simple sugars and energy-dense foods over nutrient-rich alternatives has a variety of serious health consequences, such as a heightened risk of obesity, type 2 diabetes, and cardiovascular diseases.

Unhealthy dietary preferences are partially a reflection of children’s basic biology. Children are predisposed to like sweet-tasting foods and to reject bitter-tasting foods, such as leafy green vegetables. While preferences for sweet tastes likely evolved to attract children to sources of high energy during periods of maximal growth, bitter rejection may have evolved to protect against poisoning, because many toxic substances are bitter and distasteful. Consequently, preferences for bitter foods
(e.g., dark-green vegetables) are largely learned through early sensory experiences.

Sensory experiences begin before birth with the emergence of the chemosensory system. As shown in Figure 1, during gestation, the fetus is exposed to flavors from their mother’s diet in the amniotic fluid. Infants who are breastfed continue to experience these flavors in breast milk. Through these early sensory experiences, infants learn to like a variety of flavors that are characteristic of the culinary traditions of their family and of the foods their mother will later feed them. Opportunities to develop healthy flavor preferences do not end with gestation or breastfeeding. After the introduction of solid foods, parents continue to play a powerful role in shaping children’s flavor preferences by determining which foods will be made available to their children,
and how they will be prepared and flavored. Continued exposure to flavors of a variety of healthy foods, such as fruit and vegetables, during 

complementary feeding promotes familiarization of their sensory properties and in turn enhances acceptance of these foods as well as acceptance of novel foods. It is important to note that the process of familiarizing infants with these healthful foods may require patience. Although children will easily accept energy-dense foods and beverages that are high in sugar and salt upon initial presentation, 8–10 exposures to vegetables may be required in order to overcome children’s inherent dislike for vegetables [2]. The ease with which children accept new foods will also depend on their age, as new foods are more readily accepted by infants than toddlers. As young children advance into their second year of life, food preferences and acceptance become influenced by social determinates. For example, parents influence children’s eating habits through modeling their own eating behaviors. Research shows that children try new foods more quickly and like healthy foods better when consumption of those foods is modeled by a parent [3]. Children will also learn to associate
foods with emotional tone of social interactions during feeding. For example, repeated opportunities to taste a vegetable in a positive context with a parent increases its acceptance [4].

From an early age, children learn how and what to eat, and develop expectations about how foods should taste [5]. This learning occurs as a result of the interplay between children’s biological predispositions, the food environment provided by their parents, and the community and culture in which they live. Parents vary dramatically in the food environment that they provide their children, which in turn is determined in part
by their demographic and cultural background (as depicted in Figure 1).

Developing strategies that empower parents from all backgrounds to provide children healthy foods in a supportive feeding environment is critical for promoting the development of preferences for healthy foods.

References
1. Miles G, Siega-Riz AM: Trends in food and beverage consumption among infants and toddlers: 2005–2012. Pediatrics 2017;139:e201632.
2. Forestell CA, Mennella JA: Early determinants of fruit and vegetable acceptance. Pediatrics 2007;120:1247–1254.
3. Draxten M, Fulkerson JA, Friend S, et al: Parental role modeling of fruits and vegetables at meals and snacks is associated with children's adequate consumption. Appetite 2014;78:1–7.
4. Remington A, Anez E, Croker H, et al: Increasing food acceptance in the home setting: a randomized controlled trial of parent-administered taste exposure with incentives. Am J Clin Nutr 2012;95:72–77.
5. Mennella JA, Reiter AR, Daniels LM: Vegetable and fruit acceptance during infancy: impact of ontogeny, genetics, and early experiences. Adv Nutr 2016;7:211S–219S.
 

 

Abstract

To understand the development of children’s flavor preferences, it is important to consider
the context of the feeding environment. Although children are predisposed to prefer sweet tasting foods and beverages and to avoid bitter-tasting foods such as dark-green vegetables, parents can play a central role in shifting these innate food acceptance patterns throughout development. Beginning before birth, the fetus detects the continually changing flavor profile of amniotic fluid, which reflects the mother’s diet. After birth, if mothers choose to breastfeed, these sensory experiences continue. Through this process of familiarization, women who maintain a healthy diet throughout pregnancy and lactation prepare their infants to like healthful foods. Upon the introduction of solid foods, repeated exposure to a variety of healthful foods promotes acceptance for these foods and for novel foods. In addition to providing sensory exposures to a range of healthful foods, parents can shape children’s flavor preferences by modeling healthy eating behaviors and by creating supportive feeding environments. The degree to which parents engage in these practices is influenced by demographic and societal characteristics. Considering the context in which children and families live will encourage the development of evidence-based strategies that more effectively support children’s healthy eating habits. 

Introduction

Children consume fewer fruits and vegetables than recommended, and their diets are high in saturated fat, sugar, and salt. In the USA, more than 25% of toddlers do not consume a single serving of fruits or vegetables on any given day [1], and their consumption of sweet and salty snacks and sugar-sweetened beverages is rising [2]. The preference for simple sugars and energy-dense foods over nutrient-rich alternatives has a variety of serious health consequences, such as type 2 diabetes, cardiovascular disease, and heightened risk of obesity. Because the first 1,000 days of life are considered a critical period for obesity prevention efforts [3], it is important to understand the factors that are related to the development of early preferences for nutritious, healthful foods. Children’s unhealthy dietary preferences reflect their basic biology. As previously reviewed [4], heightened preference for intense sweetness and rejection of bitter tastes are innate and considered to be a hallmark of youth. Within hours of birth, infants demonstrate a preference for sweet taste. They consume more of a sweet-tasting liquid relative to plain water [5], and they display facial expressions of relaxation and pleasure in response to a sweetened solution placed on the tongue [6]. Although preference for sweet taste remains elevated throughout childhood, it begins to decline in adolescence [7]. In contrast, children’s response to bitter-tasting foods is decidedly negative. For example, neonates respond with gapes, nose wrinkles, and frowns after a small amount of a bitter solution is placed in the oral cavity [6]. Beginning
around 2 weeks of age, infants consume less of a bitter-tasting urea solution relative to water [8]. Infant’s rejection of bitter tastes, which continues throughout childhood, explains why they often refuse to eat many vegetables, particularly those of the Brassica genus (e.g., broccoli or Brussels sprouts), which are high in bitter polyphenols.
These responses seem maladaptive in today’s society where we have easy accessto tasty, energy-dense foods. However, if we consider taste perception from an evolutionary perspective, its adaptive role becomes apparent. Acceptance of sweet taste likely evolved to enhance survival in an environment where nutrients and sources of energy were scarce, thereby attracting children to available sources of nutrients and energy during periods of maximal growth. In contrast, perception and dislike of bitter taste may have evolved to protect against the high risk of accidentally ingesting lethal toxins which often taste bitter [9]. Although early preference for sweet taste and avoidance of bitter taste is inborn, an important feature of the gustatory system is that it is inherently plastic, especially during infancy and childhood. Consequently, children can learn to like bitter foods through early sensory experiences.
Parents’ dietary habits shape the availability of and accessibility to foods in the home [10], and, as a result, they play a central role in providing early sensory experiences that cultivate children’s palates. With this in mind, the goal of this paper is to review recent research with a focus on the role of parents in the development of children’s early flavor preferences, especially for bitter green vegetables. I will focus on flavor learning over the first 1,000 days, beginning with conception until the end of the second year of life. As will be reviewed below, evidence suggests that a range of external factors, such as culture, socioeconomic status, and food availability, influences dietary choices that parents make for themselves and for their families (Fig. 1). As a result, these factors should be considered when developing evidence-based strategies that endeavor to increase bitter green vegetable acceptance and consumption in young children. 

Perinatal Sensory Experiences and the Role of the Mother

Flavor experiences begin before birth with the emergence of the olfactory and gustatory
systems. As reviewed in more detail elsewhere [11], by the last trimester, the taste and olfactory systems are functional and capable of detecting and communicating information to structures in the brain responsible for organizing and controlling affective behaviors. By term, infants are actively swallowing between 500 and 1,000 mL of amniotic fluid per day, which stimulates the taste buds and olfactory cells. The early development of the taste and olfactory systems allows infants to detect the continually changing flavor profile of the amniotic fluid. In addition to containing chemicals with distinct taste properties, a wide variety of volatile chemicals that are either ingested (e.g., fruits, vegetables, and spices) or inhaled (e.g., cigarette smoke) by the mother are transmitted to the amniotic fluid. Research suggests that early sensory experiences that occur during pregnancy are encoded, and these memories subsequently play a role in the acceptance of solid foods (for a review see Spahn et al. [12]). Consistent evidence
shows that prenatal flavor exposure increases acceptance of similarly flavored foods during infancy and childhood. Although more research is needed to investigate how long these early flavor memories facilitate food acceptance, one study has shown that prenatal flavor exposures may have long term effects. In this study, 8- to 9-year-old children who were exposed prenatally to garlic ate a higher proportion of garlic-flavored compared to plain potato in a laboratory session compared to children who were not exposed to garlic prenatally [13].

After birth, infants’ flavor experiences continue as they begin to consume either formula or breast milk. Compared to formula feeding, breastfeeding provides children with an advantage in developing preferences for healthy foods, especially if mothers have healthy dietary habits. Like that of amniotic fluid, the flavor profile of breast milk reflects the foods eaten by the mother and her culinary traditions. Exposure to flavors transmitted to breast milk from the mothers’ diet facilitates infants’ acceptance of solid foods. In a recent study, Mennella et al. [14] demonstrated that breastfed infants whose mothers consumed a variety of vegetable juices for 1 month during lactation were more accepting of carrot-flavored cereal relative to a control group of breastfed infants whose mothers avoided the vegetable juices. Earlier exposure to vegetables through mother’s breast milk, beginning 2 weeks postpartum, was more effective than later exposure that began either 6 or 10 weeks postpartum. Other research has suggested that mothers’ vegetable consumption during breastfeeding may have long-term consequences on flavor preference development. This was supported by a recent study of 1,396 mother-child dyads that controlled for socioeconomic status and fruit and vegetable availability during childhood [15]. This study reported that among children breastfed for at least 4
months, each additional serving of vegetables consumed by lactating mothers significantly increased the odds that vegetable consumption would be high (i.e., ≥1
daily serving) at 6 years of age. In combination, these studies suggest that mothers’ vegetable consumption as well as a longer duration of breastfeeding may facilitate
children’s preferences throughout childhood.

Environmental Factors That Limit Newborns’ Exposure to Flavors of Healthful Foods

The transition from pregnancy to the postpartum period may be associated with a negative impact on maternal dietary habits, especially in low-income women. Although women who breastfeed report higher fruit and vegetable intake than women who bottle feed [16], the prevalence of exclusive breastfeeding over the first 6 months of life is low in the USA. While more than two-thirds of women (81%) initiate breastfeeding at birth, only 20% are still breastfeeding by the time their child reaches 6 months of age. These statistics vary by racial background, with African American women experiencing some of the lowest breastfeeding rates nationally (i.e., 64% initiate breastfeeding and only 14% are exclusively breastfeeding at 6 months) [17]. One important reason for the cessation of breastfeeding before 6 months of age in the USA is that women often return to work only 2–3 months after the birth of the child. In an attempt to overcome this challenge, changes in federal policy over the past decade now require workplaces
to provide lactation rooms for breastfeeding mothers. While this policy change has increased breastfeeding duration for some women, those who are more disadvantaged continue to experience workplace disparities that limit their ability to sustain breastfeeding [18].

In combination, these findings suggest that many infants in the USA do not
experience the benefits associated with breastfeeding throughout the first 6 months of life. Evidence shows that education interventions as well as social support, regardless of whether it is from a family member, friend, health care provider, or the workplace, increase breastfeeding. However, more research is needed to identify effective system level policies and practices to increase rates of breastfeeding [19].

Parents’ Role in Complementary Feeding

Although there is wide variation in the introduction of solid foods, parents are advised to introduce solid foods at around 6 months of age. During this new stage of feeding, interactions between the infant and the parent become increasingly inter dependent and bidirectional. Healthy feeding practices during this period have positive short- and long-term effects on body composition and growth, neurodevelopment, and the development of healthy preferences for healthy foods [20]. During complementary feeding, parents continue to play a powerful role in shaping children’s flavor preferences by determining which foods are available, and how they will be prepared and flavored. Through these early experiences, children learn about the sensory properties of foods and develop schemas about how an acceptable food should look, taste, and smell. As will be reviewed, laboratory- based studies have identified several strategies for promoting infants’ and toddlers’ preferences for vegetables.

Parents’ Role in Providing Sensory Exposures during Complementary Feeding

During complementary feeding, continued and repeated exposure to the flavors
of healthful foods promotes familiarization with their sensory properties and, in turn, enhances acceptance of these foods. It is important to note that the process of familiarizing children with healthful foods may require patience. Although children will easily accept energy-dense foods and beverages that are high in sugar and salt upon initial presentation, less palatable foods typically require more presentations before they are readily accepted. In a recent study, after 5 exposures to an artichoke purée, toddlers consumed more of this vegetable and continued to accept it when tested 5 weeks after the intervention [21]. This study also assessed the role of associative learning by comparing the effectiveness of repeated exposure to plain artichoke purée to that of a purée with calories (flavor- nutrient learning) or a sweet taste (flavor-flavor learning). Results indicated that flavor-nutrient and flavor-flavor pairings increased children’s acceptance of the artichoke purée to the same extent as repeated exposure to the plain version [21]. Overall, studies that have compared effects of associative conditioning with repeated exposure during infancy have yielded mixed findings, with several studies suggesting that repeated exposure is just as effective as associative conditioning at increasing children’s consumption of vegetables.

There is significant variation between cultures with respect to the timing of
introducing vegetables. Recent research suggests that the order in which parents
introduce fruits and vegetables may be important for long-term vegetable acceptance.
In one example, infants were exclusively fed either vegetables or fruits during the first 2 weeks of complementary feeding. Several months later, when the infants were 12 months old, vegetable intake was 38% higher in those who were initially exposed to vegetables relative to those initially exposed to fruits [22]. These results, in combination with those from other studies, suggest that exposing children to vegetables early during complementary feeding may be an effective approach to increase later vegetable acceptance. There is growing evidence that exposing infants and toddlers to a variety of vegetables is another effective method for increasing vegetable acceptance. A
recent study showed that this approach may be especially effective for children who are weaned at around 6 months of age [23]. Infants who were either weaned between 4 and 5 months and those who were weaned between 5.5 and 6 months were exposed to 1 vegetable (carrots) or to a variety of vegetables (i.e., courgette, parsnip, or sweet potato) over 9 days. When infants were fed a novel vegetable (peas) in the test phase, those weaned after 5 months consumed significantly more after exposure to a variety of vegetables than those who were exposed to only 1 type of vegetable. In contrast, infants who were weaned earlier showed similar acceptance of the peas regardless of whether they had been fed a variety of vegetables or a single vegetable.

In combination, studies focused on complementary feeding suggest that to increase children’s vegetable acceptance, mothers should introduce their infants to a wide range of vegetables and continue to offer those that are not initially accepted. Timing is also important, with evidence supporting early rather than later exposure to vegetables. Despite this scientific evidence, there is a wide range of attitudes and beliefs about solid food introduction across the world. For example, although vegetables are commonly the first food offered in many European countries, the types of vegetables offered are typically root vegetables, such as potatoes and carrots, rather than bitter green vegetables. In North America and Australia, more than half of children are initially fed infant cereals rather than vegetables [24]. Moreover, in North America, the commercial foods that are available for infants and toddlers may not promote the development of preferences for bitter green vegetables. A recent analysis of infant and toddler foods available in US supermarkets indicated that most single ingredient vegetables were red and orange vegetables. A minority of foods contained bitter green vegetables, such as spinach. In these foods, small quantities of green vegetables were
mixed with more palatable vegetables or fruit [25].

Parents’ Role in Socially Facilitating Flavor Preferences during Complementary Feeding

Although infants are relatively accepting of new foods soon after weaning, during the second year of life, they begin to become hesitant to accept new foods. This phenomenon, known as food neophobia, is associated with reduced fruit and vegetable acceptance and causes great frustration in parents. The feeding environment that parents create at this time sets the stage for the development of healthy flavor and food preferences that may eventually overcome neophobic responses [for a review, see ref. 26]. Parents can encourage children’s healthy eating habits by employing an authoritative feeding style in which they take responsibility for their child’s nutritional
choices while providing a positive feeding environment that is supportive and responsive to the child’s needs. In contrast, authoritarian feeding styles that involve
coercive feeding practices are associated with more food refusals [27]. Infants and
toddlers may also learn to associate foods with emotional tone of social interactions
during feeding. For example, research with 3- to 4-year-old children has shown that
repeated opportunities to taste a vegetable in a positive context where a parent
praises the child for trying it increased its acceptance relative to repeated exposure
alone [28]. Parental dietary habits also play an important role in encouraging acceptance of healthy foods. Ideally, if parents have a healthy diet themselves they will
not only feed some of these foods to their toddlers, they will also model their own healthy eating habits. Children will try new foods more quickly and like healthful foods better when a parent models the consumption of those foods [29].

Environmental Limitations That Reduce Infants’ and Toddlers’ Access to Healthful Foods

One important factor that affects children’s exposure to healthful foods in the home is the socioeconomic status of the family. Underprivileged families often have difficulty accessing and feeding healthy foods to their children because they live in areas that have limited access to nutritious foods, or they cannot afford to buy these foods. This issue combined with the short shelf life of fresh products or a lack of resources (such as a stove) to prepare the foods make it difficult to prepare meals that contain vegetables. To help mitigate some of these problems, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in the USA provides healthful foods and support services to low-income pregnant and postpartum women and their children up to 5 years of age. Although this program does not address all of the challenges listed above, WIC participation has been shown to increase children’s consumption of green vegetables and lentils and decrease consumption of saturated fats over the first 2
years of life [30]. Moving forward, it will be important to develop and assess the
effectiveness of additional interventions that involve tailored guidance and education
about healthy eating to families.

Final Thoughts
From an early age, children learn how and what to eat, and develop expectations about how foods should look, taste, and smell. This learning occurs as a result of the interplay between children’s biological predispositions, the food environment provided by their parents, and the community and culture in which they live. Mothers who consume an array of healthful foods throughout pregnancy and lactation – and who subsequently feed their children these foods during the complementary feeding period – can promote healthful eating habits in their children. However, due to a variety of social, economic, and cultural factors, parents vary dramatically in the food environment that they provide. Developing effective strategies that empower parents from all backgrounds to provide
children with exposure to healthful foods in a supportive feeding environment is critical for promoting healthy dietary habits.

Conflict of Interest Statement
The author has no conflicts of interest to disclose related to the preparation of this article.

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