Promoting healthy food preferences from the start: a narrative review of food preference learning from the prenatal period through early childhood

The palatable, energy‐dense foods that characterize modern environments can promote unhealthy eating habits, along with humans' predispositions to accept sweet tastes and reject those that are sour or bitter. Yet food preferences are malleable, and examining food preference learning during early life can highlight ways to promote acceptance of healthier foods. This narrative review describes research from the past 10 years focused on food preference learning from the prenatal period through early childhood (ages 2–5 years). Exposure to a variety of healthy foods from the start, including during the prenatal period, early milk‐feeding and the introduction to complementary foods and beverages, can support subsequent acceptance of those foods. Yet development is plastic, and healthier food preferences can still be promoted after infancy. In early childhood, research supports starting with the simplest strategies, such as repeated exposure and modelling, reserving other strategies for use when needed to motivate the initial tasting necessary for repeated exposure effects to begin. This review can help caregivers and practitioners to promote the development of healthy food preferences early in life. Specific implementation recommendations, the role of individual differences and next steps for research in this area are also discussed.     

Prevention of overweight and obesity in children: influences on the food environment

PURPOSE: There is an epidemic of pediatric overweight and obesity leading to type 2 diabetes in youth. The purpose of this review is to describe the multiple paths of influence on the food environment of youth and to identify diabetes education strategies focused on early prevention of overweight and obesity. METHODS: A review of relevant professional literature was conducted. RESULTS: Models of obesity prevention in youth need to address genetic factors that influence the development of food preferences in the young child, parenting influences on eating pattern development, and access and availability of foods in the physical environment of the child. CONCLUSIONS: Early intervention with parents of young children is required to prevent the development of eating patterns that lead to pediatric obesity and type 2 diabetes in youth. Diabetes educators need to be able to inform parents of the multiple paths of influence on the food environment of the child and suggest strategies to encourage the development of positive food preferences and intake.     

Childhood obesity: a societal problem to solve

In contrast to other threats to American children's health, the treatment and prevention of childhood obesity are considered the responsibility of individual children and their parents. This pressure exists in the context of the societal stigmatization of overweight children and the powerful environmental inducements aimed directly at children to eat nutritionally poor foods. Parents of overweight children are left in the difficult position of fearing the social and health consequences of their child's obesity, and fighting a losing battle against the omnipotent presence of the media and constant exposure to unhealthy foods. This paper brings together several literatures to provide a comprehensive examination of the major challenges facing obese children and their families. In particular, this paper documents the extent of stigmatization towards overweight children and reviews evidence of the conflicting advice given to parents about how to help children develop healthful eating in the face of biological and learned food preferences. We conclude with a call for a shift in thinking about the role of our society in the aetiology, treatment and prevention of childhood obesity.     

Food and activity preferences in children of lean and obese parents.

BACKGROUND: Children of obese parents have a substantially higher risk of adult obesity than children of lean parents. Adoption and twin studies have shown that this risk is largely genetic but the proximal mechanisms of the genetic risk are not known. Comparisons of energy intake or expenditure in children of obese and lean parents have produced mixed, but generally negative results. An alternative hypothesis is that the early expression of obesity risk is through food and activity preferences, which provides a basis for later weight gain. The aim of this study was therefore to compare food and activity preferences in a large sample of young children from obese and lean families using parental obesity as a marker of the obesity-risk phenotype. Because the children from the families with obese parents were not yet overweight, differences observed in the two types of families are more likely to be causes than effects of obesity. METHODS: A total of 428 children aged 4-5 y, whose parents were either obese/overweight or normal-weight/lean were selected from a population sample of families with twin births. Food and activity preferences were assessed with a combination of food intake and taste tasks, and questionnaires completed by the mother during a home visit. FINDINGS: Children from the obese/overweight families had a higher preference for fatty foods in a taste test, a lower liking for vegetables, and a more 'overeating-type' eating style. They also had a stronger preference for sedentary activities, and spent more time in sedentary pastimes. There were no differences in speed of eating or reported frequency of intake of high-fat foods. CONCLUSION: Part of the process whereby a genetic risk of obesity is transmitted to the next generation could be through differences in diet and activity preferences, which would place susceptible individuals at risk of positive energy balance in the permissive nutritional environment of industrialised countries today.     

Complementary foods and flavor experiences: setting the foundation

Increased fruit and vegetable consumption early in life may lead to life-long intake of fruits and vegetables, which in turn may be beneficial for weight control and other health outcomes in later life. Although health officials worldwide recommend delaying solid foods until 6 months of age, younger infants often receive solid food, which may affect later obesity rates. The timing of introduction to solid foods is important both nutritionally and developmentally and may affect acceptance of foods both in infancy and later in life. Infants can clearly discriminate the flavors of different fruits and vegetables. Repeated flavor experiences promote the willingness to eat a variety of foods: infants will consume more of foods that have a familiar flavor and are more accepting of novel flavors if they have experience with flavor variety. Many flavors that the mother either ingests or inhales are transmitted to her milk and/or amniotic fluid. Mothers can help the transition from a diet exclusively of milk or formula to a mixed diet by providing the infant familiar flavors in both milk or formula and solid foods. Exposure to a variety of flavors during and between meals appears to facilitate acceptance of novel foods. Providing novelty in the context of a familiar food might prove to be an optimal combination to progressively accustom infants to a diversity of novel foods. When repeatedly exposing infants to flavors of some vegetables that have bitter tastes, mothers should focus not on infants' facial expressions but on their willingness to eat the food and should continue to provide repeated opportunities to taste the food. Introducing children repeatedly to individual as well as a variety of fruits and vegetables, both within and between meals, might help them be more accepting of fruits and vegetables, which is difficult to enhance beyond toddlerhood.     

Asthma and food allergy

PURPOSE OF REVIEW: Food allergy associated clinical and social burdens have increased substantially in prevalence in the past decade. Coexisting asthma is a significant problem as food reactions tend to be more severe when they involve the lung. Food allergy also increases asthma morbidity in adults and children. RECENT FINDINGS: Especially in early infancy, food allergy can be related to the development of future asthma. For diagnosis, cut-off values are very important for both specific IgE levels and skin-prick test when interpreting food allergy. For the treatment, oral immunotherapy is showing promise for refractory patients with IgE-mediated food allergies. SUMMARY: Food allergies can be classified as IgE-mediated or non-IgE-mediated. Besides foods, some additives and preservatives can also trigger asthma in certain people. Asthma may develop in about 5% of individuals who suffer from food allergy and current asthma may be triggered by foods among 6-8% of children and 2% of adults. Because of the difficulty of confirming diagnosis of food allergy, novel approaches are currently being investigated and new therapy modalities are being sought. For total asthma control and for better quality of life, steps should be taken to avoid foods in cases of food allergy.     

Management of the Patient with Multiple Food Allergies

Food allergies affect 6% of children and 3% to 4% of adults in the United States. Although several studies have examined the prevalence of food allergy, little information is available regarding the prevalence of multiple food allergies. Estimates of prevalence of people allergic to multiple foods is difficult to ascertain because those with allergy to one food may avoid additional foods for concerns related to cross-reactivity, positive tests, or prior reactions, or they may be reluctant to introduce foods known to be common allergens. Diagnosis relies on an accurate history and selective IgE testing. It is important to understand the limitations of the available tests and the role of cross-reactivity between allergens. Allergen avoidance and readily accessible emergency medications are the cornerstones of management. In addition, a multidisciplinary approach to management of individuals with multiple food allergies may be needed, as avoidance of several food groups can have nutritional, developmental, and psychosocial consequences.     

The inter-generational transmission of eating disorders

A self-perpetuating cycle has been implicated between early childhood feeding problems and later eating disorders; between parental management style and eating disorders in the child; and between the way a mother was raised and her own parenting behaviour. Questionnaires were distributed to all nurseries in a discrete area of the West Midlands, to elicit information about both nursery-school children's eating behaviour, and the eating attitudes and management style of their primary caregiver. Comparisons were made between the eating behaviour of children whose caregiver showed evidence of abnormal eating attitudes, as demonstrated by their scores on BITE and EAT-26, and that of a control group drawn from the same population. Food refusal and fussiness were hypothesized to be orthogonal dimensions of eating behaviour in the child. Food refusal significantly correlated with the management style of mealtimes when there was evidence of disordered eating in the caregiver, and co-varied with the caregiver's eating attitudes. Food fussiness was seen to be relatively stable across groups, but correlated with the management style of caregivers. This supports the hypothesis that food refusal and food fussiness are distinct behaviours, rather than degrees of the same behaviour. Copyright © 1998 John Wiley & Sons, Ltd and Eating Disorders Association.     

Faim et satiété, contrôle de la prise alimentaire

Food intake is a complex periodical behaviour through which a living organism can extract vital nutrient and energy substances from the environment. Hunger and satiety are psycho-physiological states that, respectively, elicit or inhibit food intake. Homeostatic (glucostatic or lipostatic) and non-homeostatic (environmental conditions) mechanisms contribute to the periodic initiation of food intake. Once a meal has started, the stimulation to eat is progressively antagonized by the cumulative effects of the ingested foods. This satiation process brings the eating episode to an end before the ingested nutrients have been absorbed. Meal size is determined by an interaction of sensory (food quality and variety), gastro-intestinal, and neuroendocrine responses. A Pavlovian learning mechanism allows the metabolic consequences of ingesting a particular food to become associated with the sensory characteristics of the food; as a consequence, a unique repertoire of food acceptance and rejection responses is shaped for each individual eater. Satiety, the post-meal phase of inhibition of eating, depends on the nutrient composition of the meal and, mainly, on its energy density. The selection of high energy-density foods induces little satiety and favours “passive over-consumption”. In humans, culture, socio-economical status, family context, and even the physical characteristics of the environment affect food choices and energy intake. The mechanisms selected by Evolution in order to allow survival under environmental conditions of food shortage seem more efficient at correcting for energy needs than excesses. In the present context of food plethora, the obesity epidemic reflects both a biological bias and the potent stimulation from the environment.     

Update on hidden food allergens and food labeling.

This article is intended to review the current literature on "hidden" food allergens and the various ways in which sensitized individuals may be exposed to these allergens. A focus on advances in food labeling, and the Food Allergen Labeling and Consumer Protection Act (FALCPA) is also included, because it assists food-allergic consumers in the strict avoidance of specific foods. Article information was gathered primarily through a computer search of relevant data relating to human subjects. Our findings indicate that sensitized individuals can unknowingly be exposed to allergenic proteins in foods through cross-contact, food containing allergenic nonfood products, food additives, and cross-reactivity. Furthermore, food packaging and formulation errors, ingredient switching, and foods not covered under the FALCPA were also found to be sources of hidden food allergens. There are many ways in which hypersensitive individuals can be exposed to potentially dangerous allergens despite careful avoidance. Furthermore, health care providers should consider various sources of hidden allergens in food-allergic individuals with an unclear etiology. Food hypersensitivity has been identified as a significant medical dilemma in our society. Recent efforts to increase public awareness and strides made in labeling of food products are encouraging.     

Effects of a high-protein meal (meat) and a high-carbohydrate meal (vegetarian) on satiety measured by automated computerized monitoring of subsequent food intake, motivation to eat and food preferences

We have examined the effects on satiety of equicaloric meals with different protein and carbohydrate content. Twenty normal weight healthy women were served cooked lunch meals made of commonly used natural food items with either a high-protein (43 energy %) (a meat casserole) or a high-carbohydrate (69 energy %) (a vegetarian casserole) content in a counterbalanced repeated measures design. The subsequent ad libitum evening meal intake (4 h after lunch) was measured by a 'universal eating monitor' and subjective feelings of motivation to eat and food preferences were assessed repeatedly. At the subsequent evening meal subjects ate 12 per cent less (P less than 0.05) after the high-protein meal compared to the high-carbohydrate meal. There was no difference in motivation to eat between meals. This could partly be explained by a difference in palatability between the meals. The food-preference lists showed that before lunch there was relative preference for high-protein foods in favour of high-carbohydrate foods. After lunch either meal produced instead a relative 'aversion' for high-protein foods. This 'aversion' was greater after the high-protein lunch meal than after the high-carbohydrate lunch meal.     

Food Intolerances and Eosinophilic Esophagitis in Childhood

Food intolerance is an adverse reaction to a particular food or ingredient that may or may not be related to the immune system. A deficiency in digestive enzymes can also cause some types of food intolerances like lactose and gluten intolerance. Food intolerances may cause unpleasant symptoms, including nausea, bloating, abdominal pain, and diarrhea, which usually begin about half an hour after eating or drinking the food in question, but sometimes symptoms may delayed up to 48 h. There is also a strong genetic pattern to food intolerances. Intolerance reactions to food chemicals are mostly dose-related, but also some people are more sensitive than others. Diagnosis can include elimination and challenge testing. Food intolerance can be managed simply by avoiding the particular food from entering the diet. Babies or younger children with lactose intolerance can be given soy milk or hypoallergenic milk formula instead of cow’s milk. Adults may be able to tolerate small amounts of troublesome foods, so may need to experiment. Eosinophilic esophagitis (EE) is defined as isolated eosinophilic infiltration in patients with reflux-like symptoms and normal pH studies and whose symptoms are refractory to acid-inhibition therapy. Food allergy, abnormal immunologic response, and autoimmune mechanisms are suggested as possible etiological factors for EE. This article is intended to review the current literature and to present a practical approach for managing food intolerances and EE in childhood.     

Development and modification of child food preferences and eating patterns: behavior genetics strategies

Behavioral genetics (BG) designs can offer useful strategies for studying the development of child food preferences and eating patterns. This review summarizes BG designs that tested familial influences on child eating behavior and implicated both genetic and home environmental factors. A range of BG strategies, including family and pseudo-family designs, classic twins designs, discordant sibling designs, cotwin control designs, and high-risk designs, have provided information on child development that could not have been obtained from the analysis of singletons. BG designs can provide can powerful tools for testing environmental theories of child nutrition and, potentially, for better understanding between-child variability in response to dietary interventions for overweight. The term BG may misleadingly imply only the classic twin design or just heritability estimation; BG strategies can be adapted creatively to address a range of questions concerning the development of child appetite and eating regulation.     

Energetic consequences of thermal and nonthermal food processing

Processing food extensively by thermal and nonthermal techniques is a unique and universal human practice. Food processing increases palatability and edibility and has been argued to increase energy gain. Although energy gain is a well-known effect from cooking starch-rich foods, the idea that cooking meat increases energy gain has never been tested. Moreover, the relative energetic advantages of cooking and nonthermal processing have not been assessed, whether for meat or starch-rich foods. Here, we describe a system for characterizing the energetic effects of cooking and nonthermal food processing. Using mice as a model, we show that cooking substantially increases the energy gained from meat, leading to elevations in body mass that are not attributable to differences in food intake or activity levels. The positive energetic effects of cooking were found to be superior to the effects of pounding in both meat and starch-rich tubers, a conclusion further supported by food preferences in fasted animals. Our results indicate significant contributions from cooking to both modern and ancestral human energy budgets. They also illuminate a weakness in current food labeling practices, which systematically overestimate the caloric potential of poorly processed foods.     

Dietary differences between centenarians residing in communities and in skilled nursing facilities: the Georgia Centenarian Study

The purpose of this study was to examine the dietary habits among centenarians residing in community settings (n=105) and in skilled nursing facilities (n=139). The sample was a population-based multi-ethnic sample of adults aged 98 years and older (N=244) from northern Georgia in the US. Compared to centenarians in skilled nursing facilities, those residing in the community were more than twice as likely to be able to eat without help and to receive most of their nourishment from typical foods, but they had a lower frequency of intake of all of the food groups examined, including dairy, meat, poultry and fish, eggs, green vegetables, orange/yellow vegetables, citrus fruit or juice, non-citrus fruit or juice, and oral liquid supplements. A food summary score was created (the sum of the meeting recommendations for five food groups). In multiple regression analyses, the food summary scores were positively associated with residing in a nursing facility and negatively associated with eating without help and receiving most nourishment from typical foods. These data suggest that centenarians residing in communities may have limited access to foods that are known to provide nutrients essential to health and well-being. Also, centenarians who are able to eat without help and/or who eat mainly typical foods may have inadequate intakes of recommended food groups. Given the essential role of foods and nutrition to health and well-being throughout life, these findings require further exploration through the detailed dietary analyses of centenarians living in various settings. Additional authors include S. M. Jazwinski, R. C. Green, M. Gearing, W. R. Markesbery, J. L. Woodard, J. S. Tenover, I. C. Siegler, P. Martin, M. MacDonald, C. Rott, W. L. Rodgers, and J. Arnold.     

Food allergies and food intolerances

Adverse reactions to foods, aside from those considered toxic, are caused by a particular individual intolerance towards commonly tolerated foods. Intolerance derived from an immunological mechanism is referred to as Food Allergy, the non-immunological form is called Food Intolerance. IgE-mediated food allergy is the most common and dangerous type of adverse food reaction. It is initiated by an impairment of normal Oral Tolerance to food in predisposed individuals (atopic). Food allergy produces respiratory, gastrointestinal, cutaneous and cardiovascular symptoms but often generalized, life-threatening symptoms manifest at a rapid rate-anaphylactic shock. Diagnosis is made using medical history and cutaneous and serological tests but to obtain final confirmation a Double Blind Controlled Food Challenge must be performed. Food intolerances are principally caused by enzymatic defects in the digestive system, as is the case with lactose intolerance, but may also result from pharmacological effects of vasoactive amines present in foods (e.g. Histamine). Prevention and treatment are based on the avoidance of the culprit food.     

Soul foods for some older Americans.

The elderly person brings with him a lifetime of food preferences. For him, nutritional adequacy is dependent upon continuation of similar underlying influences and the varying conditions which determine the food intake of any group. The significance of individuality cannot be minimized in assessing nutritional well-being and in developing a plan of action. Among the factors affecting food acceptance and health status are foods which are foods which are considered "soul" by some persons. Recognition of, and respect for, individual food preferences can be invaluable to members of the health professions in providing services to aging Americans.     

Eating behaviour in obese and normal weight 11-year-old children.

The eating behaviour of 23 normal weight and 20 obese 11-year-old children was measured by the computerized eating monitor VIKTOR. The total intake of food, duration of consumption, rate of consumption and the relative rate of consumption were measured during two lunch meals. Subjective motivation to eat and food preferences were also measured. The obese children ate faster (P less than 0.05) and did not slow down their eating rate towards the end of the meal (P less than 0.05) as much as normal weight children. The obese children also described themselves as having less motivation to eat before lunch than normal weight children (P less than 0.05). A deficient satiety signal or an impared response to such signals in obese subjects could possibly explain these differences found.     

Classification of Food Allergens and Cross-Reactivity

Patients with specific food allergies are commonly sensitized to related foods, for example, shrimp with other shellfish and peanut with other legumes. In some instances, this represents a true allergy to the related food, defined as cross-reactivity, while in other instances, it represents a positive skin or IgE test only, in a patient who can eat the related food without difficulty. This is defined as cross-sensitization. It is extremely important that the clinician recognize these patterns of cross-sensitization and cross-reactivity, both to counsel patients on foods that should be avoided and to make sure that foods are not unnecessarily restricted from the diet. In fact, it is very common for patients to be instructed to avoid entire food groups based just on positive tests, which leads to unnecessary dietary restrictions with effects on food choices, nutrition, and quality of life.