Conference Co-chairs and Speakers
Ronald E. Kleinman, MD, Physician in Chief, Massachusetts General Hospital for Children; Chair, Department of Pediatrics, Massachusetts General Hospital; and Charles Wilder Professor of Pediatrics, Harvard Medical School; Frank Greer, MD, Professor Emeritus of Pediatrics, University of Wisconsin School of Medicine
Beverly J. Cowart, PhD, Monell Chemical Senses Center, Philadelphia, Pennsylvania; Marion M. Hetherington, DPhil, School of Psychology, University of Leeds, England; Susan Johnson, PhD, Professor of Pediatrics, Section of Nutrition, University of Colorado Anschutz Medical Campus, and Director, The Children’s Eating Laboratory; Kathleen L. Keller, PhD, Assistant Professor, Departments of Nutritional Sciences and Food Science, The Pennsylvania State University; David Klurfeld, PhD, National Program Leader for Human Nutrition, USDA ARS; Alanna J. Moshfegh, MS, RD, Research Leader, Beltsville Human Nutrition Research Center, USDA Agricultural Research Service; Robert Murray, MD, FAAP Professor of Human Nutrition, Department of Human Sciences, College of Education and Human Ecology, The Ohio State University; Erin Quann, PhD, RD, Director, Nutrition Research, Nestlé Infant Nutrition; Jean Welsh, PhD, MPH, Assistant Professor of Pediatrics, Emory University, and Director, Research and Evaluation Team, Strong4Life (Child Obesity Prevention) Initiative, Children’s Healthcare of Atlanta
Expert Panel Members
Johanna T. Dwyer, DSc, RD, Professor of Medicine (Nutrition) and Community Health, Tufts University School of Medicine; Adjunct Professor, Friedman School of Nutrition Science and Policy, Tufts University; and Director, Frances Stern Nutrition Center, Tufts Medical Center; Fern Gale Estrow, MS, RDN, CDN Founder, FGE Food & Nutrition Team, New York, New York; David Klurfeld, PhD, National Program Leader for Human Nutrition, USDA Agricultural Research Service; Soo-Yeun Lee, PhD, Professor, Food Science and Human Nutrition, University of Illinois at Urbana-Champaign; Madeleine Sigman-Grant, PhD, RD, Professor Emerita, Maternal and Child Health, and Nutrition Specialist, University of Nevada, Reno; Joanne Slavin, PhD, RD, Professor, Department of Food Science and Nutrition, University of Minnesota; Jennifer Weber, MPH, RD, Director, Healthy Way to Grow, American Heart Association
Sylvia Rowe, MA, SR Strategy, Washington, DC; Frances A. Coletta, PhD, RD, Coletta Consulting, Burnsville, North Carolina; Liz Marr, MS, RD, FAND, Liz Marr & Associates, Longmont, Colorado
Anne Bartholomew, MS, RD, Branch Chief, Nutrition Services, Supplemental Food Programs Division, USDA Food and Nutrition Service; Dennis M. Bier, MD, Professor of Pediatrics and Director, USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, and Editor in Chief, The American Journal of Clinical Nutrition; Lynn Parker, MS, Scholar, Food and Nutrition Board, National of Medicine; Courtney Gaine, PhD, President and CEO, The Sugar Association, Washington, DC; Cheryl Diggs, Vice President Public Policy and Education, The Sugar Association, Washington, DC
These proceedings are an outcome of a roundtable held in Washington, DC, October 29 to 30, 2015. The purposes of the roundtable were to:
- provide a forum to discuss the science and research voids related to sweet taste perception and sugar intake in young children;
- discuss the role of naturally present or added sugars (AS)a as a strategy that may help parents and other caregivers to successfully transition their older infants and toddlers from complementary infant foods to consuming nutrient-dense foods from the family table;
- generate potential research ideas and questions on this topic for future guidance on the feeding of young children, including from birth to 24 months old, which is scheduled for integration into the 2020 DGA; and
- create the impetus to extend this research to public-private partnerships with industry, academia, and the government.
The roundtable was funded by the Sugar Association and planned in part by the Department of Pediatrics Section of Nutrition, University of Colorado Anschutz Medical Campus. A small planning team, including the roundtable co-chairs, identified 3 overarching subject areas for the roundtable: (1) dietary and nutrient intakes; (2) developmental feeding, including sensory aspects; and (3) factors contributing to feeding success with nutrient-dense foods. Researchers presented both established and emerging state-of-the-art science. The presenters and an expert panel engaged in active dialog throughout the roundtable to identify research priorities, as well as potential public-private collaborations and funding sources. (Event participants and observers are listed in the sidebar.)
The US Dietary Guidelines for Americans (DGA) have traditionally focused on individuals 2 years and older. In response to a growing demand for the DGA to include infants and toddlers, the US Department of Agriculture and the US Department of Health and Human Services initiated the Birth to 24 Months Topic Identification Project (B-24 project, now known as Pregnancy and Birth to 24 Months project or P/B-24 project) to develop dietary recommendations for them, as well as their parents and other caregivers,1 and, subsequently, for pregnant women.2 As part of the project process, 4 content-specific expert work groups (WGs), composed of researchers, were established according to age, as well as maternal and caregiver influences: WG 1 (0–6 months), WG 2 (6–12 months), WG 3 (12–24 months), and WG 4 (caregivers, mothers, and others). Each WG identified nutrition topics and systematic review questions specific to the period from birth to 24 months. Although all 4 WGs identified numerous research gaps, a reoccurring theme voiced by the WG 3 “period of transitional feeding (12–24 months)” was the paucity of evidence-based strategies that will support (1) feeding success during the transition to table foods and (2) the potential for lifelong healthy eating.3
One major concern that was identified is a need for research about ways to improve acceptance of nutrient-dense foods, including vegetables.4 This issue was recognized in a 2015 American Academy of Pediatrics (AAP) policy statement, applying specifically to school-age children.5 The AAP committee cited research that infants are born with a strong innate liking for sweetness,6 hypothesizing that using small amounts of sugar with highly nutritious foods may enhance enjoyment and consumption during later infancy and early childhood.5
A Historical Look at Dietary Guidance for Infants and Toddlers
At the beginning of the 20th century, very few nutrients had established “requirements,” even in adults (and vitamins had not yet been identified). Even 30 to 40 years later, the concept that children had nutrient requirements that were distinct from those of adults was new. As the evidence base for dietary recommendations evolved and entered the published medical literature, periodic updates were made to textbooks used by clinical practitioners and healthcare organizations to reflect this growth of information.
In 1958, the first report of the AAP Committee on Nutrition (CON) stated that developmental maturity of the gut and neuromuscular system, growth rate, and activity level were the most appropriate indicators for determining when to introduce solid foods to infants rather than relying on age alone.7 This seminal report established the conceptual framework for the late infancy and early childhood feeding recommendations published in all of the following 7 editions of the AAP’s Pediatric Nutrition Handbook. This framework has evolved into an evidence-based model for recommendations concerning the feeding of infants, toddlers, and young children as they transition from an exclusively fluid diet of breast milk or formula to the addition of pureed infant foods and fortified cereals and ultimately to a variety of nutrient-dense foods from the family table.8
Developmental readiness, feeding practices, and age-appropriate nutrient requirements are 3 key facets of infant and child feeding recommendations.
One of the most important contributions of the AAP CON positions during the years was to integrate the 3-faceted framework into infant and child feeding recommendations by considering developmental readiness, feeding practices, and age-appropriate nutrient requirements (see Figure 1). Because the recommendations included in the DGA have been limited to individuals 2 years and older, the Pediatric Nutrition Handbooks have continued to be the only authoritative reference on dietary guidance for US infants and children younger than 2 years. This 3-faceted framework could also be used by the 2020 Dietary Guidelines Advisory Committee as it integrates the B-24 age group into its report.
Consumption Patterns Among Toddlers
Starting life with good feeding habits is important. However, sustaining and adapting healthy eating patterns through toddlerhood are imperative as the child transitions from a diet of primarily breast milk or infant formula to the foods of the family, subsequently setting the framework for increasing the chances of healthy eating in adulthood. Toddlers’ diets often mirror the dietary problems of older children and adults, which fall short on recommended intake of certain foods, including vegetables, and this is evident by the second year of life.9
This section summarizes these food and beverage consumption patterns, as well as nutrient intake, among US toddlers. This information establishes the groundwork for the following section on developmental feeding. Although not addressed at the roundtable, oral and dental health is another consideration and is detailed in the accompanying article in this supplement.10
Dietary Variety and Vegetables: Findings From the Feeding Infants and Toddlers Study
The Feeding Infants and Toddlers Study (FITS), funded by Nestlé Infant Nutrition, is the largest and most comprehensive dietary intake survey of American parents and other caregivers of young children from birth through 4 years old to date. It provides insights on the diets, eating habits, and related lifestyle factors of infants, toddlers, and preschoolers living in the United States. The FITS is a cross-sectional 24-hour dietary recall study conducted in 200211,12 and again in 2008,13 and a new study (2015–2016) is now being completed. Because the study has been repeated at multiyear intervals, FITS can be helpful in monitoring trends in dietary intakes of young children over time.
The 2008 FITS study was conducted with parents or primary caregivers of children for a total of 3273 surveys, including infants aged 0 to 11 months (n = 887), toddlers aged 12 to 23 months (n = 925), and preschoolers aged 24 to 47 months (n = 1461).13 During the roundtable, the researchers reviewed data from this survey to examine vegetable consumption patterns during the first few years of life to help better understand opportunities for improvement, and the following analysis of intake on a given day was presented at the roundtable.
Few children received complementary foods before 4 months old.14 Vegetables were among the first foods, beginning at 4 to 5 old months for approximately 25% of infants.15 This is in line with the time frame recommended for introducing complementary foods by the AAP CON.16 On any given day, consumption of vegetables (ie, vegetables not included in food mixtures such as pasta or casseroles) rose to 63% for infants between 6 and 8 months old15 and to approximately 70% for infants between 9 and 47 months old.15,17
Similar to findings with vegetables, approximately 30% of toddlers and preschoolers were not eating a discrete portion of fruit.17 On the other hand, approximately 85% of children consumed some type of sweetened beverage, dessert, sweet, or salty snack in a day.17 When looking at the contribution of foods to total calorie intake, an overall dietary pattern that was low in vegetables and fruits (7% and 4% of total energy intake, respectively) and higher in grains and sweets (32% and 15% of total energy intake, respectively) emerged at 12 months old and was fairly consistent by 24 months old, reflecting similar food choices to those reported for older children and adults.18 Parents were aware that their child’s diet quality declined after infancy19; however, most parents thought that their child’s diet contained enough fruits and vegetables (83% of parents of older infants, 84% of parents of toddlers, and 74% of parents of preschoolers).
Food, Beverage, and Nutrient Intakes of US Toddlers
An additional cross-sectional dietary intake data set is the What We Eat in America component of the 2011–2012 National Health and Nutrition Examination Survey. The What We Eat in America includes nationally representative 1-day dietary data of US toddlers 12 to 35 months old, excluding those who are breastfed (n = 469),20 which was analyzed to assess food, beverage, and nutrient intakes. The findings of this study were presented at the roundtable and are detailed in an accompanying article in this supplement.21
Similar to FITS, the proportion of toddlers in this study that did not consume any fruit on the intake day was 30%. The proportion that did not consume any vegetables on the intake day was 43%, which is somewhat higher than the FITS findings. Although intake (excluding dietary supplements) met recommendations for many nutrients, many food and beverage choices were not nutrient dense. This study found that AS provided toddlers with an average of 10% of their daily energy intake, which is in line with the 2015–2020 DGA. However, approximately 40% of toddlers had daily intakes exceeding this level.
Toddler’s Dietary Intake of Added Sugars
Although young children are known to have a preference for sweet-tasting foods and beverages, there has been little study of the role that sugars play in either promoting or compromising intake of other nutrients. National Health and Nutrition Examination Survey 2009–2010 and 2011–2012 data together with the Food Patterns Equivalents Database were analyzed to estimate daily intake of sugars in the diets of US children younger than 2 years, with an emphasis on AS consumption during the early toddler period, and to identify demographic, environmental, and dietary factors associated with this intake. The findings of this study were presented at the roundtable and are detailed in an accompanying article in this supplement.22
This research shows that most of the sugars consumed by infants and toddlers were naturally occurring sugars, most of which were dairy sugars (lactose). The prevalence of AS consumption rose from 61% among infants to 99% among toddlers. Mean daily intake of AS among toddlers was 8.4% of their total energy intake. The leading sources of AS tended to be foods and beverages that lack the nutrients important for the diets of young children.
Taken together, these cross-sectional studies show that, for toddlers, (1) consumption of AS approaches the limit recommended by the 2015–2020 DGA for the prevention of obesity and chronic disease, (2) a large percentage of them are not consuming fruits and vegetables on a given day, and (3) consumption of non–nutrient-dense foods and beverages is commonplace. It is evident that improvement in young children’s vegetable consumption is needed and that parents and other caregivers need guidance, particularly at the vulnerable time between 12 and 24 months old when children are transitioning to the family table and early dietary habits are formed.
The early years represent a critical period for the development of food acceptance and preferences. The trajectory of food acceptance represents a complex mix of biology, environmental factors, and learning. Children readily accept sweet and salty foods because of innate taste preferences and often initially reject low–energy dense foods, particularly those that are bitter and sour.23 Low acceptance and intake of vegetables in infancy and early childhood reflect these tendencies.15 Early experience also has a powerful role in food acceptance in childhood and beyond.24–26 To explore these issues, presenters addressed the development of satiety mechanisms, origin and modification of sweet taste preferences, and flavor-flavor learning (FFL) specific to vegetable feeding.
Development of Satiety Mechanisms in Toddlers
A widely accepted assumption in the child feeding literature is that humans are born with the ability to regulate energy intake,27–30 yet the data to support this assertion are minimal.
An understanding of factors influencing appetite and satiety during development is critical.
Factors in the prenatal and postnatal environment can interfere with or enhance the development of satiety mechanisms and promote subsequent excess weight gain and the development of healthy weight control. Mode of feeding (breast or bottle feeding with formula or breast milk),31 introduction of complementary foods,32 intake of juices and sugar-sweetened beverages, parental attention to children’s hunger and satiety cues, and other parental feeding practices such as pressuring children to eat33–35 have all been reported to have an impact on the development of satiety mechanisms in children. In addition, exposure to large portions of highly palatable foods may also promote excess intake.36–38 There is also evidence that children’s responsiveness to satiety cues may be a heritable trait that is expressed early in life and tracks into adulthood,39,40 To date, there have been few studies to successfully demonstrate that it is possible to teach children to self-regulate their energy needs. Additional research is needed to inform the evidence base around the factors that influence the development of self-regulation of energy intake in children.
Origin and Modification of Sweet Preferences
In examining ways to improve toddlers’ diets, a critical area of exploration is how experiential factors, specifically dietary exposures to sweet taste, modify or enhance sweet preference and subsequent consumption of sweet-tasting foods.
The gustatory system, which detects the basic taste qualities of sweet, salty, sour, bitter, umami (savory), and perhaps fat, is a primitive one. Responses to these taste stimuli are, to a large extent, hardwired in the brain.41 In particular, sweet is hedonically positive, and bitter is hedonically negative. This is generally true from the time of birth, if not in utero, until death.
Taste receptors are located primarily in the taste buds on the papillae of the tongue. Sweet, umami, and bitter tastes are encoded by G-protein–coupled receptors.42 Despite the wide array of structurally diverse compounds that can elicit sweet tastes, only a single receptor—the dimer of T1R2+T1R3 proteins—seems to be responsible for most sweet tastes.43,44 Taste receptors send messages to the brain via 3 cranial nerves, which first connect with neurons in a part of the brainstem known as the nucleus of the solitary tract. From there, communication with other brain areas seems to follow at least 2 pathways. A reflex pathway is confined to the brainstem and underlies behaviors that are automatically elicited by tastes (eg, eating and rejection reflexes such as licking and gagging) (see Figure 2). These behavioral responses occur even in infants lacking a forebrain. Other ascending pathways send taste information to higher brain areas. Notably, especially in the case of sweet, 1 site of termination is in the limbic system, including the hypothalamus and amygdala—areas associated with the recognition of reward and addiction.45,46 Taste physiology is described in further detail in this supplement.47
The unlearned preference for sweet is apparent in several convergent measures of newborn responses to sweet tastes.48 Specifically, both term and preterm infants show preference for sweet through increased relative intake of sweet solutions, enhanced sucking responses, positive facial expressions, and heightened heart rate. Moreover, in addition to being an innately preferred taste, sweetness masks unpleasant, largely bitter tastes in foods for both adults and, perhaps especially, young children, which also contributes to the preference for sweetened foods and beverages.49
That is not to say that group and individual differences in preferred levels of sweetness and/or intraindividual shifts in those levels do not occur. There is a well-documented downward shift in the level of preferred sweetness from adolescence to adulthood, paralleling the downward shift in the need for nutrient-dense foods as humans end their growth phase.50 Similarly, multiple studies have shown that African Americans, both children and adults, express higher sweet preferences than whites.51 Moreover, recent studies point to genetic factors as important determinants of an individual’s sweet taste perception, although perhaps less so in childhood than in adulthood.52–54
Finally, several studies have documented changes in preference for sweet in specific food contexts as a result of dietary experience. Studies show that infants who were routinely fed sugar water in early infancy showed, at both 6 months and 2 years old, an enhanced preference for sugar in water relative to those who were not.55,56 However, at 2 years old, preference for sweetness in a Kool-Aid beverage was identical for these 2 groups. Similarly, other research shows enhanced preference for a sweetened (or salted) novel food with repeated exposure that did not generalize beyond the particular food/flavor complex to which they were exposed24 (see further discussion of FFL hereinafter).
In summary, the taste system is a potent monitor of food intake. Sweetness is an innately preferred taste that can enhance intake of foods, perhaps especially ones with a bitter taste component. Preferred levels of sweetness vary among age and racial groups and may in some cases reflect individual genetic variation. Dietary experience can also affect sweet preferences. However, experimental evidence suggests that this primarily influences the context in which sweetness is expected or preferred, not general levels of preferred sweetness.
Flavor-flavor Learning and Vegetable Feeding
Vegetable intake among children remains relatively low despite government-sponsored efforts to encourage children to eat more vegetables.25 One suggestion for this, among many, is that children do not like the taste of bitter vegetables. Because bitter tastes are avoided in early life, pairing the novel taste of a food with an existing, familiar, and well-liked food or flavor might enhance acceptance of the target food (FFL). A second possible explanation is that parents also do not eat enough vegetables and so they do not serve them to their children. Another reason might be that vegetables are low in energy density and high in water content, so providing additional energy might increase their acceptance through flavor-nutrient learning (FNL).
Two qualitative studies (England57 and France58) and 1 quantitative study (United Kingdom, France, and Denmark59) were conducted to examine how mothers introduce vegetables to their babies during complementary feeding. Mothers disclosed some interesting methods to enhance intake, including adding vegetable flavor (an actual puree or the liquid that the vegetable had been cooked in) to milk, hiding vegetables among already liked meals (vegetables by stealth), adding salt, and using sweet condiments such as apple sauce or ketchup to mask the distinctive flavor of novel vegetables.57,58
Through the EU-funded VIVA and HabEat projects, a series of experiments were conducted to test the hypothesis that FFL might enhance acceptance and intake of vegetables in early life.59,60 In 1 series of studies conducted in the United Kingdom, Denmark, and France, novel vegetable intake (an artichoke) among children aged 4 to 38 months (n = 332) was compared when given plain, with sugar (FFL), or with added energy through oil (FNL).59 Across these studies, no additional benefit of FFL or FNL was found over mere exposure.
In another randomized controlled trial, researchers exposed weaning-age infants to plain milk or vegetable puree added to milk and then to plain cereal or vegetable puree added to cereal to test whether FFL would promote vegetable acceptance at weaning.61 In this study, mothers were randomized to an intervention group (IG; n = 18, 6 breast-fed) or a control group (CG; n = 18, 6 breast-fed). The IG infants received 12 daily exposures to vegetable puree added to milk (days 1–12) and then 12 × 2 daily exposures to vegetable puree added to rice at home (days 13–24). Plain milk and rice were given to CG. Then, both received 11 daily exposures to vegetable puree. Intake was weighed, and liking was rated on days 25 to 26 and 33 to 35 after the start of complementary feeding in the laboratory, supplemented by the same data recorded at home. Vegetables were rotated daily (carrots, green beans, spinach, broccoli). Intake, liking, and pace of eating were greater for IG than CG infants. Thus, there is some evidence that, in early life, specifically during complementary feeding, pairing a familiar, sweet taste (milk or cereal) with a novel flavor food (vegetable) can enhance intake and acceptance of that food. However, more research is needed.
THE PATH FORWARD
Several roundtable presentations addressed some of the wide ranging challenges in evidence-based dietary guidance for toddlers, including (1) interpretation of guidance by practitioners and media, as well as parents and other caregivers, and (2) principles for public-private partnerships to address research gaps. In addition, proposed research was presented that would explore strategies to suppress aversive sensations from vegetables and assess whether doing so enhances caregiver persistence in offering vegetables to toddlers.
Unique Challenges of Incorporating Developmental Taste Preferences Into B-24 Nutrition Policy
The importance of the opportunity to shape early food experiences and establish sound eating habits through new dietary guidelines is obvious but also raises questions, which are explored in depth in an accompanying article in this supplement62 and summarized hereinafter.
First experiences with food are formative, and a wide array of factors influences children’s early dietary patterns. By the age of 2 years, the child’s diet will mirror that of the family, making existing family habits a significant factor in establishing and maintaining good dietary habits in the toddler.63,64
In the B-24 period, as well as for Americans 2 years and older, building a dietary pattern based on a diverse set of nutrient-dense foods from each of the 5 food groups—vegetables, fruits, (whole) grains, dairy, and protein sources—is aimed at nutrition adequacy. Limiting excess energy and specific nutrients that can undermine long-term health (such as saturated fats, sodium, and AS) targets the prevention of chronic diseases. Within the 2015 DGA, these 2 aspects are complementary, and individual food choices within healthy eating patterns are emphasized.65
Unfortunately, guidance aimed at limiting intake of certain foods or nutrients may not be helpful in practice. This advice, as filtered through the media, as well as some professionals and researchers, is at times presented as rigid, simplistic, or even nutritionally harmful directives. Such misinterpretation may already be occurring with the current renditions of the DGA for Americans 2 years and older, and the potential for such needs to be considered with any recommendations for the B-24 age group.
There are many ways to foster a young child’s exploration of new tastes, textures, and combinations of foods.66,67 These strategies are detailed in an accompanying article in this supplement.67
The 2020 Dietary Guidelines for Americans will be important for setting age-appropriate developmental expectations for parents and other caregivers, and for crafting federal programs for infants and young children.
The DGA 2020 development process will be a highly visible forum in which to set developmentally appropriate expectations for parents and other caregivers. Government feeding programs, such as those for school meals and vended foods, now are modeled on the DGA.68 Adding infant and toddler dietary guidelines would extend the influence of the DGA process to additional safety net programs, such as the Special Supplemental Feeding Program for Women Infants and Children. The clarity of future B-24 dietary guidance will be of utmost importance to its interpretation and adoption by all relevant stakeholders (parents and other caregivers, food industry, healthcare).
Public-Private Partnerships: Principles
At the meeting, roundtable participants considered the funding challenges for nutrition research. The Interagency Committee on Human Nutrition Research is a federal group that includes all 20 government agencies with an interest in nutrition and is co-chaired by representatives from the US Department of Agriculture and the Department of Health and Human Services. A subcommittee of the Interagency Committee on Human Nutrition Research was established to focus on the collaborative process that would foster the establishment of public-private partnerships to combine the expertise and resources of government, academia, and industry to answer nutrition research questions beyond what any individual sector could do on its own. A stakeholder meeting held in December 2014 resulted in 12 final consensus principles detailed in an article published in the American Journal of Clinical Nutrition.69 The principles were subsequently endorsed by the American Society for Nutrition, the Academy of Nutrition and Dietetics, the American Gastroenterological Association, the Institute of Food Technologists, the International Association for Food Protection, and the International Life Sciences Institute North America, collectively representing approximately 113 000 professionals. The application of the guiding principles for nutrition research is aimed at enhancing public confidence in the transparency, structure, and results derived from such activities.
Developmental Feeding and Proposed Research for Building Evidence-Based Guidelines for Young Children
During the meeting, roundtable participants considered proposed research that would explore the use of minimal amounts of AS to reduce children’s initial rejection of bitter vegetables and the potential impact on parents and other caregivers’ willingness to persevere. Limited evidence indicates that the timing of exposure to vegetables during the first 2 years of life is critically important for subsequent acceptance. Both early (<6 months old) and later (>9 months old) vegetable exposures have been observed to have negative associations with food acceptance in childhood.70,71 Exposure that is consistent and persistent has been repeatedly observed to improve children’s food acceptance.72 Critically, parents and other caregivers—typically mothers—do not persist in offering foods that they perceive their children do not like or to which they react strongly.73 No study has investigated how to improve maternal persistence in offering a vegetable that she perceives her young child to dislike.
Individual characteristics, such as genetically based responses to bitter taste, have been associated with children’s food acceptance and vegetable intake. A key feature of many vegetables, especially green vegetables, is bitterness arising from a number of components (eg, phenols, flavonoids, isoflavones, terpenes, and glucosinolates).74 Studies that aim to overcome children’s initial rejection of vegetables have done so through repeated exposure paradigms and by FFL (eg, providing a familiar dip to eat with vegetables or sweetening vegetables).75,76 The effects of FFL—over and above repeated exposure—may be partially ascribed to reducing negative sensory effects (ie, masking bitterness centrally with concomitant sweetness). Notably, such studies have focused almost exclusively on children’s reports of liking and intake of the target vegetable.
The literature reports that mothers attend to the amounts that their children consume to make decisions about their child’s acceptance.77,78 However, they also report being sensitive to when their child finds a food to be distasteful or when food is wasted because of food rejection.79 Mothers report that negative feeding interactions are extremely stressful and unpleasant. Research focused on suppressing aversive sensations, as well as improving caregiver persistence in offering foods that are initially less preferred, is needed to enhance interventions to improve children’s diets. These strategies are detailed in an another article in this supplement,67 as well as the following section on research priorities.
PRIORITIES FOR RESEARCH
Before the roundtable, the following research questions were circulated. Can low levels of sugar in foods help
- Promote success in the caregiver-child feeding experiences of nutrient-dense foods?
- Encourage toddlers to accept and consume vegetables with a bitter taste profile? And, once bitter profiles are reduced by the addition of small amounts of sugars, can acceptance of these foods be sustained when the addition of sugars is withdrawn?
- Promote acceptance and enjoyment of a variety of nutrient-dense foods but without a concomitant increase in a desire for sweet foods in later childhood?
- Set the stage for lifelong healthy eating?
Throughout the roundtable, participants discussed research gaps and related strategies for achieving a nutrient-dense diet for toddlers aged 12 to 24 months as they transition to table foods. Using the framework of the key questions posed previously, posed before the workshop, additional research questions posed by participants during the conference were categorized under the following 5 areas representing research gaps:
- Caregiver-Child Feeding Experience
- • Can low levels of sugars in foods help:
- o Promote a positive mother-child feeding relationship?
- o Provide more positive feeding experiences for “picky eaters”?
- o Lead to more enjoyable family mealtimes (promote family meals rather than being fed before the family eats)?
- o Improve knowledge of developmental norms and their impact on caregiver’s perception, stress, and persistence for reoffering rejected foods?
- • Can parents and other caregivers be trained to use routine feeding times as an opportunity to engage in back-and-forth communication with their child that enhances the child’s willingness to try novel feeding experiences?
- • Can low levels of sugar in foods encourage toddlers to accept and consume vegetables with a bitter taste profile and maintain acceptance when AS is withdrawn?
- • Which vegetables are being defined as nutrient dense, and which nutrients do they supply?
- • What would be the minimal level of sugar to add to various bitter-flavored vegetables that would result in high food acceptance?
- • Are there critical windows in time during which the child learns that certain foods should be sweet versus not sweet, that is, context-specific learning?
- • Do nutrient-dense bitter-tasting vegetables have the potential to contribute enough nutrients to the toddler diet to warrant targeting for AS?
- • In practice, would the use of low levels of sugars as a feeding strategy to encourage acceptance of bitter vegetables among toddlers be potentially misinterpreted or misapplied by mothers?
Lifelong Healthy Eating
- • If research shows a minimal level of AS results in an increased intake of bitter vegetables, can this feeding strategy also be used to increase intake of other poorly accepted nutrient-dense foods (eg, whole grains)?
- o Would different amounts of sugar or other caloric sweeteners be needed for improving the consumption of different kinds of poorly accepted nutrient-dense foods?
- • Can knowledge of individuals’ taste receptor polymorphisms (sweet, bitter, etc) be used to develop personalized nutrition products?
- • Are there differences in sweet preferences among different ethnicities (black, Hispanic, Asian, Native American, etc) at ages 12 to 24 months that could be determined by experimental evidence from populations across the globe?
- • Can parents and other caregivers be encouraged to alter early cuisine rules to promote dietary variety?
- • Does preference for sweetness track in individuals over time, for example, from infancy throughout the life course?
- • Would adding sugar contribute to appetite stimulation and/or excess calorie consumption, and would there be different outcomes for toddlers at risk for overweight?
- • Would the feeding strategy of adding a small amount of sugar to poorly accepted nutrient-dense foods impact dental health in toddlers?
General Research Questions
- Given the reality that funding for behavior change research is limited, what is needed to encourage a larger funding stream?
- Are randomized controlled trials the only research design for evidence-based feeding recommendations for infants and toddlers?
- Can recommendations for toddler feeding be made more evidence based by targeted research?
- Can different parenting styles in early childhood with respect to imbuing a preference or aversion to sweet taste, as well as various related attitudes and beliefs, be linked to future health outcomes, including body weight?
In summary, the roundtable concluded the following:
- Infant and toddler feeding recommendations are best considered using a 3-faceted framework that considers developmental readiness, feeding practices, and age-appropriate nutrient requirements.
- Children readily accept sweet and salty foods because of their innate taste preferences and often initially reject foods, particularly those that are bitter and sour. However, research is needed to understand whether the inborn taste preference for sweetness can be used strategically to improve acceptance of foods that are important sources of nutrients required for health, growth, and development, while potentially supporting the development of lifelong healthy eating patterns. A particular focus is needed for vegetables, which are underconsumed during the toddler years and thereafter.
- Further research is also needed to understand the role of the caregiver, in particular, their persistence, in offering vegetables during late infancy and toddler years and how that relates to the development of food preferences and eating patterns in childhood and beyond.
1. Raiten DJ, Raghavan R, Porter A, Obbagy JE, Spahn JM. Executive summary: evaluating the evidence base to support the inclusion of infants and children from birth to 24 mo of age in the Dietary Guidelines for Americans—“the B-24 Project.”. Am J Clin Nutr
3. Atkinson S. Evidence and research gaps on toddlerhood: period of transitional feeding (12–24 months). In: Raiten D, Hubbard V, eds. The B-24 Project: Evaluating the Evidence to Support the Inclusion of Infants and Children up to 24 Months of Age in the Dietary Guidelines for Americans
. Presented during the scientific session at the 2013 American Society of Nutrition, Experimental Biology; April 20, 2013. Accessed January 7, 2017.
4. Birch LL, Doub AE. Learning to eat: birth to age 2 y. Am J Clin Nutr
5. American Academy of Pediatrics, Committee on Nutrition, Council on School Health. Snacks, sweetened beverages, added sugars, and schools. Pediatrics
6. Mennella JA, Ventura AK. Early feeding: setting the stage for healthy eating habits. Nestle Nutr Workshop Ser Pediatr Program
7. American Academy of Pediatrics Committee on Nutrition. On the feeding of solid foods to infants. Pediatrics
8. American Academy of Pediatrics Committee on Nutrition. Pediatric Nutrition Handbook
. 1–7 ed. Evanston, IL: American Academy of Pediatrics; 1979–2014.
9. Johnson SL. Developmental and environmental influences on young children’s vegetable preferences and consumption. Adv Nutr
10. Palmer CA. Oral and dental health considerations in feeding toddlers. Nutr Today
. 2017;52(2 Suppl):S69–S75.
11. Dwyer JT, Suitor CW, eds. Feeding Infants and Toddlers Study 2002. J Am Diet Assoc
12. Monsen ER. Feeding Infants and Toddlers Study 2002. J Am Diet Assoc
13. Briefel RR. The Feeding Infants and Toddlers Study 2008. J Am Diet Assoc
14. Dwyer JT, Butte NF, Deming DM, Siega-Riz, Reidy KC. Feeding Infants and Toddlers Study 2008: progress, continuing concerns, and implications. J Am Diet Assoc
15. Siega-Riz AM, Deming DM, Reidy KC, Fox MK, Condin E, Briefel RR. Food consumptions patterns of infants and toddler: where are we now? J Am Diet Assoc
16. American Academy of Pediatrics Committee on Nutrition. Pediatric Nutrition Handbook
. 7th ed. Evanston, IL: American Academy of Pediatrics; 2014.
17. Fox MK, Condon E, Briefel RR, Reidy KC, Deming DM. Food consumption patterns: are they starting off on the right path: J Am Diet Assoc
. 2010;110(12 suppl):S52–S59.
18. Reidy K, Deming D, Fox MK, Briefel R. Development of dietary patterns in very young children: food sources of energy. FASEB J
19. Briefel RR, Deming DM, Reidy KC. Parents’ perceptions and adherence to children’s diet and activity recommendations: the 2008 Feeding Infants and Toddlers Study. Prev Chronic Dis
20. Centers for Disease Control and Prevention. National Health and Nutrition Examination Survey: 2011–2012 data documentation, codebook, and frequencies. Centers for Disease Control and Prevention National Center for Health Statistics Web site. http://wwwn.cdc.gov/nchs/nhanes/2011–2012/DR1IFF_G.htm
. Accessed October 5, 2015.
21. Moshfegh AJ, Rhodes DG, Goldman JD, Clemens JC. Characterizing the dietary landscape of children, 12 to 35 months old. Nutr Today
. 2017;52(2 Suppl):S52–S59.
22. Welsh AJ, Figueroa J. Intake of added sugars during the early toddler period. Nutr Today
. 2017;52(2 Suppl):S60–S68.
23. Mennella JA. Ontogeny of taste preferences: basic biology and implications for health. Am J Clin Nutr
24. Sullivan SA, Birch LL. Pass the sugar, pass the salt: experience dictates preference. Dev Psychol
25. Johnson SL, Bellows L, Beckstrom L, Anderson J. Evaluation of a social marketing campaign targeting preschool children. Am J Health Behav
26. Caton SJ, Ahern SM, Remy E, Nicklaus S, Blundell P, Hetherington MM. Repetition counts: repeated exposure increases intake of a novel vegetable in UK pre-school children compared to flavour-flavour and flavour-nutrient learning. Br J Nutr
27. Fomon SJ, Filmer LJ Jr, Thomas LN, Anderson TA, Nelson SE. Influence of formula concentration on caloric intake and growth of normal infants. Acta Paediatr Scand
28. Birch LL, Deysher M. Conditioned and unconditioned caloric compensation: evidence for self-regulation of food intake in young children. Learn Motiv
29. Lumeng JC, Patil N, Blass EM. Social influences on formula intake via suckling in 7- to 14-week-old-infants. Dev Psychobiol
30. Birch LL, Johnson SL, Andersen G, Peters JC, Schulte MC. The variability of young children’s energy intake. N Engl J Med
31. Li R, Scanlon KS, May A, Rose C, Birch LL. Bottle-feeding practices during early infancy and eating behaviors at 6 years of age. Pediatrics
32. Brown A, Lee MD. Early influences on child satiety-responsiveness: the role of weaning style. Ped Obes
33. Johnson SL, Birch LL. Parents’ and children’s adiposity and eating style. Pediatrics
34. Rhee KE, Lumeng JC, Appugliese DP, Kaciroti N, Bradley RH. Parenting styles and overweight status in first grade. Pediatrics
35. Rodgers RF, Paxton SJ, Massey R, et al. Maternal feeding practices predict weight gain and obesogenic eating behaviors in young children: a prospective study. Int J Behav Nutr Phys Act
36. Fisher JO, Liu Y, Birch LL, Rolls BJ. Effects of portion size and energy density on young children’s intake at a meal. Am J Clin Nutr
37. Fisher JO, Kral TV. Super-size me: portion size effects on young children’s eating. Physiol Behav
38. Kling SM, Roe LS, Keller KL, Rolls BJ. Double trouble: portion size and energy density combine to increase preschool children’s lunch intake. Physiol Behav
39. Llewellyn CH, van Jaarsveld CH, Johnson L, Carnell S, Wardle J. Nature and nurture in infant appetite: analysis of the Gemini twin birth cohort. Am J Clin Nutr
40. Llewellyn CH, Trzaskowski M, van Jaarsveld CH, Plomin R, Wardle J. Satiety mechanisms in genetic risk of obesity. JAMA Pediatr
42. Kinnamon SC. Taste receptor signaling—from tongues to lungs. Acta Physiol
43. Nelson G, Hoon MA, Chandrashekar J, Zhang Y, Ryba NJ, Zuker CS. Mammalian sweet taste receptors. Cell
44. Li X, Staszewski L, Xu H, Durick K, Zoller M, Adler E. Human receptors for sweet and umami taste. Proc Natl Acad Sci U S A
45. Sugita M, Shiba Y. Genetic tracing shows segregation of taste neuronal circuitries for bitter and sweet. Science
46. Small DM. Individual differences in the neurophysiology of reward and the obesity epidemic. Int J Obes (Lond)
. 2009;33(suppl 2):S44–S48.
47. Hayes JE, Johnson SL. Sensory aspects of bitter and sweet tastes during early childhood. Nutr Today
. 2017;52(2 Suppl):S41–S51.
48. Cowart BJ. Development of taste perception in humans: sensitivity and preference throughout the life span. Psychol Bull
49. Mennella JA, Reed DR, Mathew PS, Roberts KM, Mansfield CJ. “A spoonful of sugar helps the medicine go down”: bitter masking by sucrose among children and adults. Chem Senses
50. Mennella JA, Bobowski NK. The sweetness and bitterness of childhood: insights from basic research on taste preferences. Physiol Behav
. 2015;152(pt B):502–507.
51. Mennella JA, Lukasewycz LD, Griffith JW, Beauchamp GK. Evaluation of the Monell forced-choice, paired-comparison tracking procedure for determining sweet taste preferences across the lifespan. Chem Senses
52. Fushan AA, Simons CT, Slack JP, Manichaikul A, Drayna D. Allelic polymorphism within the TAS1R3 promoter is associated with human taste sensitivity to sucrose. Curr Biol
53. Mennella JA, Finkbeiner S, Lipchock SV, Hwang LD, Reed DR. Preferences for salty and sweet tastes are elevated and related to each other during childhood. PLoS One
54. Hwang LD, Zhu G, Breslin PA, Reed DR, Martin NG, Wright MJ. A common genetic influence on human intensity ratings of sugars and high-potency sweeteners. Twin Res Hum Genet
55. Beauchamp GK, Moran M. Dietary experience and sweet taste preference in human infants. Appetite
56. Beauchamp GK, Moran M. Acceptance of sweet and salty tastes in 2-year-old children. Appetite
57. Caton SJ, Ahern SM, Hetherington MM. Vegetables by stealth. An exploratory study investigating the introduction of vegetables in the weaning period. Appetite
58. Schwartz C, Madrelle J, Vereijken CM, Weenen H, Nicklaus S, Hetherington MM. Complementary feeding and “donner les bases du goût” (providing the foundation of taste). A qualitative approach to understand weaning practices, attitudes and experiences by French mothers. Appetite
59. Caton SJ, Blundell P, Ahern SM, et al. Learning to eat vegetables in early life: the role of timing, age and individual eating traits. PLoS One
60. Remy E, Issanchou S, Chabanet C, Nicklaus S. Repeated exposure of infants at complementary feeding to a vegetable puree increases acceptance as effectively as flavor-flavor learning and more effectively than flavor-nutrient learning. J Nutr
61. Hetherington MM, Schwartz C, Madrelle J, et al. A step-by-step introduction to vegetables at the beginning of complementary feeding. The effects of early and repeated exposure. Appetite
62. Murray RD. Influences on the initial dietary pattern among children from birth to 24 months. Nutr Today
. 2017;52(2 Suppl):S25–S29.
63. Altman J, Spahn J, Stoody EE, Rihane C, Casavale KO, Olson R. Laying the foundation for expanding the Dietary Guidelines for Americans to address children from birth to 24 months and women who are pregnant. J Acad Nutr Diet
64. Butte NF, Fox MK, Briefel RR, et al. Nutrient intakes of US infants, toddlers, and preschoolers meet or exceed dietary reference intakes. J Am Diet Assoc
. 2010;110(12 suppl):S27–S37.
65. US Department of Health and Human Services and US Department of Agriculture. 2015–2020 Dietary Guidelines for Americans
. 8th ed. 2015:13–36.
66. Rollins BY, Savage JS, Fisher JO, Birch LL. Alternatives to restrictive feeding practices to promote self-regulation in childhood: a developmental perspective. Pediatr Obes
67. Johnson SL, Hayes JE. Developmental readiness, caregiver and child feeding behaviors, and sensory science as a framework for feeding young children. Nutr Today
. 2017;52(2 Suppl):S30–S40.
68. Yaktine AL, Murphy SP. Aligning nutrition assistance programs with the Dietary Guidelines for Americans. Nutr Rev
69. Alexander N, Rowe S, Brackett RE, et al. Achieving a transparent, actionable framework for public-private partnerships for food and nutrition research. Am J Clin Nutr
70. Mennella JA, Nicklaus S, Jagolino AL, Yourshaw LM. Variety is the spice of life: strategies for promoting fruit and vegetable acceptance during infancy. Physiol Behav
71. Blissett J, Fogel A. Intrinsic and extrinsic influences on children’s acceptance of new foods. Physiol Behav
72. Skinner JD, Carruth BR, Bounds W, Ziegler P, Reidy K. Do food-related experiences in the first 2 years of life predict dietary variety in school-aged children? J Nutr Educ Behav
73. Goodell LS, Johnson SL, Antono AC, Power TG, Hughes SO. Strategies low-income parents use to overcome their children’s food refusal. Matern Child Health J
74. Tepper BJ. Nutritional implications of genetic taste variation: the role of PROP sensitivity and other taste phenotypes. Annu Rev Nutr
75. Keller KL. The use of repeated exposure and associative conditioning to increase vegetable acceptance in children: explaining the variability across studies. J Acad Nutr Diet
76. Bouhlal S, Issanchou S, Chabanet C, Nicklaus S. “Just a pinch of salt.” An experimental comparison of the effect of repeated exposure and flavor-flavor learning with salt or spice on vegetable acceptance in toddlers. Appetite
77. Mennella JA, Nicklaus S, Jagolino AL, Yourshaw LM. Variety is the spice of life: strategies for promoting fruit and vegetable acceptance during infancy. Physiol Behav
78. Forestell CA, Mennella JA. Early determinants of fruit and vegetable acceptance. Pediatrics
79. Johnson SL, Goodell LS, Williams K, Power TG, Hughes SO. Getting my child to eat the right amount. Mothers’ considerations when deciding how much food to offer their child at a meal. Appetite
aRelated to this age group and roundtable, sugars can be defined as sugars from a variety of sources, including those inherent in, as well as those added to, food, such as sucrose during the feeding or cooking process.
Appendix. Complete Author Disclosures
Drs. Cowart, Hetherington, Keller, Murray, and Welsh received travel expenses and honoraria from The Sugar Association for their participation in the conference and in the preparation of this article. Dr Coletta and Ms Marr received travel expenses and payment from the association for their participation in this conference and in the preparation of this article. Dr Kleinman received payment for travel expense and an honorarium from the association for his participation in the conference, but did not receive an honorarium for the preparation of this article. Dr Greer received payment for some travel expenses but did not receive an honorarium from the association for his participation in the conference or for the preparation of this article. Drs Johnson and Klurfeld, and Ms. Moshfegh did not receive travel expenses or honoraria from the association for their participation in this conference or in the preparation of this article.
Dr Kleinman receives support from the American Academy of Pediatrics as Editor of the AAP publication, Pediatric Nutrition, and compensation for serving on a scientific advisory board for General Mills and as an advisor to Sesame Street. He has received support from Mead Johnson Nutritionals, the Alliance for Potato Research and Education and Beechnut Hero in the past. Dr Greer has received financial support from the AAP as an editor of Pediatric Nutrition. The Sugar Association has been a sponsor of Monell Chemical Senses Center, Dr Cowart’s employer, in the past 36 months, contributing unrestricted funds. She had also received a grant from ILSI North America in the past. Dr Hetherington is currently an ad hoc teacher at the University of St Andrews and was an examiner with the University College of London. She has also received occasional honoraria from universities (as above), European government agencies for reviewing, and from Elsevier as an editor. Dr Johnson has received a grant from the National Institutes of Health, USDA, and The Sugar Association. She had also received support from the Health and Human Services, National Dairy Council, Alliance for Potato Research & Education, The Bel Group, The Institute of Medicine, and the Society for Nutrition Education and Behavior. Dr Keller has received a grant from McCormick Science Institute. Dr Klurfeld serves as a nutrition consultant on formulations and problems customers might have for Dyets, Inc. which manufactures diets for laboratory animals. Dr Murray serves as a consultant for the Sabra Dipping Company, the Egg Nutrition Council, and the Haas Avocado Board. He is also a consultant and speaker for the National Dairy Council, Dannon Company, and Abbott Nutrition. Dr Coletta serves as a consultant to the American Beverage Association and The Sugar Association, and was previously a consultant to the Alliance for Potato Research and Education. She has received support from Hero/Beechnut in the past. Ms Marr serves as a consultant to the Produce for Better Health Foundation, The Sugar Association, and was previously a consultant to Foodservice Solutions, The J.M. Smucker Company, and USDA. Ms Moshfegh and Dr Welsh do not have any conflicts of interest to disclose.