Development of Food Preferences April 2014 Development of Food Preferences In Utero to Early Childhood: Implications for Healthy Diets & Obesity Prevention Basic Terminology Gustatory Sensory system for the System sensation of taste Olfactory System Sensory system for the sensation of smell Taste Results from activation of gustatory system; 5 sensations: sweet, salty, bitter, sour & umami Flavor Results from integration of gustatory & olfactory sensations; e.g. vanilla, strawberry Executive Summary Food preferences begin developing before birth, and can have a lasting effect on ones food choices, and thus, on ones health. Preference for a food is the top determinant for consumption of that food. Consumption of fruits and vegetables is inversely associated with obesity and related chronic diseases. This m akes food preferences a potential area for intervention and prevention efforts. Food preferences are not easy to change later on in life, and there is, in fact, a sensitive period during infancy and early childhood. Thus, understanding how taste and food preferences develop m ay provide useful insight. “Infancy and early childhood has been shown to be a sensitive period for food preference development” 1 Page 1 1
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Development of Food Preferences April 2014 The Power of Taste Food preferences that have developed by early childhood can have a lasting impact on food choices throughout the life cycle. How do we define “food preference”? Food preference is comprised of taste and flavor preferences, which incorporate sensory input from the 3
gustatory and olfactory systems. Texture is also an important aspect 3
of food preference. There is no set measure to assess early developmental food preferences, but general guidelines maintain that preference for a greater variety of foods predicts better health 1,3,4,5
outcomes.
Food preferences are malleable and do change throughout 1,3,
the life stages. However, there is adulthood. Food preference is the number one determinant of food 3
choice. In other words, people eat strong evidence that food preferences and the variety of foods eaten as an infant and child are consistent with food choices later in 1,2,3,4,5 life.
foods they like. This simple, and seemingly obvious fact has important implications for public health. Diet is inextricably linked to health, and we know that a poor diet is particularly tied to obesity and other related chronic diseases. Thus, promoting healthy foods during critical periods of food preference formation may be an important new angle for obesity prevention and health promotion. Importance and Potential Impact of Food Preferences Food preferences begin forming in 1,3,8
utero and continue to have lasting effects on food choices into What are infants and toddlers eating? According to the most recent d ata from the Feeding Infants and Toddlers study (2008)6: •
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Many infants (< 1 year) do not eat any fruits or vegetables on a given day The m ost commonly consumed vegetable: French fries •
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Consumption of desserts, sweets, and sweetened beverages is declining, but remains high More infants are being breastfed for longer Fewer infants are receiving complementary foods before age 6 months s2 Development of Food Preferences April 2014 Critical Periods of Development Stage Age In Utero Conception – Birth Breastfeeding 0 – 6 months, exclusively; up to 2 years Begin at 4 – 6 months Complimentary Feeding Weaning 4 – 24 months Food Neophobia 2 – 5 years In Utero Human beings first begin to discern flavors while in the womb, as the gustatory and olfactory systems 1,8
develop. The m other’s amniotic fluid contains flavor molecules from her diet, which become the baby’s 1,3,8
first taste exposures. Repeated exposure to flavors while in the womb have been shown to increase preference for those flavors during 1,8
breastfeeding and weaning. Recommendations: •
Pregnant women should eat a healthy diet with a wide variety of fruits and vegetables in order to “prime” their children for later acceptance of a variety of healthy foods Breastfeeding By the end of the gestation period, the gustatory and olfactory systems 1
are fully developed, and the newborn is ready to taste and smell. Taste molecules from the mother’s diet are also present in her breast 1
milk. The flavor of the m ilk varies as she consumes different foods, providing the infant with exposure to novel tastes. Formula, however, has a consistent taste. This denies formula-­‐fed infants that valuable exposure to new flavors. Recommendations: •
Initiate complimentary feeding 5
between 4 and 6 m onths •
Continue breastfeeding through 3
two years, or beyond Recommendations: •
Mothers should breastfeed exclusively for 6 m onths, and 1,3
continue for up to two years •
Lactating women should consume a healthy, varied diet Introducing Complementary Foods This period m arks the beginning of the transition from a breast milk diet to a diet of family foods. At this point, innate preferences that are common among infants and children become apparent. Sweet and umami flavors are positively received, while sour and bitter foods are negatively 1
received. This is attributed to an innate preference for energy-­‐dense foods, and an aversion to rotten or poisonous foods. Premature or delayed introduction of solid foods may result in a reduction of 5 acceptance of new foods later on.
At every stage of growth, variety of foods and repeated exposure increase food acceptance. Weaning Here we refer to weaning as the period from the introduction of complimentary foods to the cessation of breastfeeding. The innate preferences and distastes are modifiable with repeated exposure s3 1
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Development of Food Preferences 3,4,5
to new foods or disliked foods. Studies consistently show that 8-­‐10 exposures are required before an increase in consumption and preference for a novel or disliked •
Children’s facial expressions can be misleading when tasting novel foods; instead, respond to the child’s actual intake of the 3
food 3
food is observed. However, m ost parents give up after five or fewer 3
attempts. Additionally, exposure to the food must include tasting it. Visual exposure to a novel food and information about the food do not appear to increase acceptance or 3
preference. Exposing infants and toddlers to a variety of flavors throughout weaning makes them 3,5 more likely to accept novel foods.
This acceptance does not cross food groups, however, so exposure to a variety of fruits does not increase 3
acceptance of a novel vegetable. Early and frequent exposure to a variety of textures is also associated with increased acceptance of a 3 variety of foods in later years.
Recommendations: •
Persevere and expose children to novel and previously disliked foods at least 8-­‐10 times April 2014 •
Prepare and expose child to a variety of foods in each food 3
group, in a variety of textures •
Rotate foods that are introduced at each meal or snack, rather than having one new food repeated for days, to increase 3
variety in the diet Food Neophobia Beginning around age two, toddlers begin exhibiting an aversion to novel, and even previously liked, foods.1,2,3 This is attributed to adaptive behaviors regarding food safety: w hen presented w ith numerous new foods, the child wants to eat familiar foods that are known to be safe. Unsurprisingly, food neophobia is associated with lower d iet quality and variety.3 The strongest predictors of food acceptance at this stage are sweetness and familiarity,3 which can prove challenging. However, repeated exposure can decrease neophobic behavior, with anywhere 1,2,3
from 6 to 15 exposures needed. A positive social environment during feeding has been shown to be especially effective in reducing 1
neophobic behavior. Children also seem to prefer new foods when they 3
are paired with energy-­‐dense foods. Recommendations: •
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Patience and perseverance with repeated exposures Maintain a positive environment for feeding Try pairing a novel or disliked food with an energy-­‐dense food Begin with foods in each category that are naturally sweeter (e.g. carrots) Biological, Social, and Environmental Influences Heritability of Food Preferences Research shows that food preferences are partially linked to 1,2,3
genetics. Protein foods, fruits, vegetables, and desserts are all 2
particularly heritable. Food 2
neophobia is also highly heritable. However, children of picky eaters are not doomed. Genetic expression of these traits is largely modified by social and environmental factors. Social Facilitation Parental feeding practices can have a significant effect on the eating behaviors of children. As previously mentioned, a positive environment improves food acceptance and 2
variety . On the other hand, forcing specific foods, pressuring, and offering bribes or contingencies may increase consumption of these foods in the short term, but in the long run, preference for the target food 1,2,3
decreases dramatically. These types of behavior send the wrong message to the child: the food is not worthwhile on its own. Similarly, restriction of specific foods (usually those high in salt, sugar, and fat) increases a child’s preference for 2
that food . Here, the message is that this food is highly desirable and special. In this way, adults (and peers) can be effectively used to promote children’s acceptance of novel foods by modeling and 2
facilitating beneficial behaviors. s4 4
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Development of Food Preferences Areas for Future Research •
More robust data on infant and child eating patterns •
Most favorable windows or sensitive periods for introducing different foods •
Long-­‐term impact of weaning practices •
Racial, ethnic, socioeconomic, and other population differences The Food Environment Cyclical Impact In addition to defining the social context that surrounds eating, parents also control the food 2
environment of the child. Parents decide the kinds of foods that are available in the home, and determine how much is served to the child. Logically, the foods that parents eat strongly predict the foods that their 4
children eat. Researchers have specifically documented a resemblance in fruit and vegetable intake between mothers and their 2
children . The directionality of this relationship is unclear, though: Does the child eat what the mother buys, or does the m other buy what the child likes? The tightly interwoven relationship between parental food preferences and eating habits and those of their children needs further research. As children reach school age, they begin spending m ore time outside the home. Other social and From the research, we can uncover a potential cycle of low food preferences that can trap families and communities in poor health. During the sensitive period for food preference development, children are almost solely exposed to foods that their parents eat. If the parents have minimal or unhealthy food preferences, they are likely to transfer them to their children. These genetic traits will be reinforced by the social and environmental factors. When that child grows up and chooses the foods their children will be exposed to, the cycle of minimal variety or food neophobia may continue. As we have said, poor dietary variety is associated with poorer health outcomes, including obesity. environmental become increasingly important, such as peer modeling 1,2
and the school environment. These social and environmental factors can reinforce or augment the earlier preferences. Recommendations: Research Challenges •
Targeting the whole family, not just child at risk for developing poor food preferences •
Many studies are observational, due to ethical concerns •
Identifying differences among specific foods can be costly and time-­‐consuming April 2014 •
Parents should m aintain a positive eating atmosphere •
Parents m odel appropriate behaviors (e.g. consuming a variety of fruits and vegetables) •
Make healthy food available, visible, and accessible (e.g. out on the counter, cut into bite-­‐
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size pieces) Current US dietary and breastfeeding guidelines align with the recommendations listed in this publication. Beyond these, there are not currently any policies that specifically support the development of food preferences. Due to the personal, familial, and cultural nature of the development of food preferences, it is difficult to design an appropriate intervention. However, public health officials and health care practitioners must continue to educate new parents about this important developmental process, and the accompanying implications for their child and their family’s health. The recommendations in this publication are an excellent tool for dissemination of this information. s5 Development of Food Preferences April 2014 References 1. Ventura AK, Worobey J. Early influences on the development of food preferences. Current Biology. 2013;23(9):R401-­‐R408. 2. Kral TVE, Rauh EM. Eating behaviors of children in the context of their family environment. Physiol. Behav. 2010;100:567-­‐573. 3. Nicklaus S. Children’s acceptance of new foods at weaning. Role of practices of weaning and of food sensory properties. Appetite. 2011;57:812-­‐815. 4. Mennella JA, Ventura AK. Early feeding: setting the stage for healthy eating habits. Nestle Nutr Inst Workshop Ser Pediatr Program. 2011;68:152-­‐168. 5. Mennella JA, Trabulsi JC. Complementary foods and flavor experiences: setting the foundation. Ann Nutr Meab. 2012;60(suppl2):40-­‐50. 6. Siega-­‐Riz AM, Deming DM, Reidy KC, Fox MK, Condon E, Briefel RR: Food consumption patterns of infants and toddlers: where are we now? J Am Diet Assoc. 2010;110:S38– S51. 7. Trabulsi JC, Mennella JA. Diet, sensitive periods in flavor learning, and growth. International Review of Psychiatry. June 2012; 24(3): 219–230. 8. Trout KK, Wetzel-­‐Effinger L. Flavor learning in utero and its implications for future obesity and diabetes. Curr Diab Rep. 2012;12:60-­‐66. s7