Sophie Nicklaus

A prospective study of food variety seeking in childhood, adolescence and early adult life.

This prospective study of food variety seeking among children was conducted between 1982 and 1999, with a follow-up in 2001-2002. Two- to three-year-old children were given a free choice of lunch foods in a nursery canteen. Their food choices were recorded and used to calculate early variety seeking scores, globally and by food group (vegetables, animal products, dairy products, starchy foods and combined dishes). The same subjects (n=339) were contacted in 2001-2002, when they were: 17-22 (n=89), 13-16 (n=68), 8-12 (n=99) and 4-7 years of age (n=83). Follow-up variety seeking, globally and by food group, and food neophobia were evaluated using questionnaire instruments. Variety seeking at follow-up increased with early variety seeking and to a lesser extent with age, and decreased with food neophobia. Early and follow-up variety seeking scores were highly related for dairy products and vegetables. Follow-up variety seeking for animal products was higher for boys and increased with age for boys, but not for girls. For each food group, variety seeking at follow-up was related to food neophobia. This study suggests that the acquisition of food repertoire may be influenced by food exposure and food choice behaviours before the age of 4.

Development of healthy eating habits early in life. Review of recent evidence and selected guidelines.

Encouraging healthy eating habit development early in life is a way to prevent the onset of diet-related diseases. This review focuses on the period ranging from the beginning of complementary feeding until the age of 3 years. Its first objective was to review relevant themes in the most recent literature on the development of healthy eating habits in this period. Its second objective was to evaluate to what extent international and national feeding guidelines cover these themes. Analysed guidelines included WHO, European Network for Public Health Nutrition, US and two European national guidelines (UK and France). They were evaluated using a 4-pt scale and compared. Well-covered themes in current literature include the influence of exposure on later acceptance, the role of variety and parental styles. Themes that occur more rarely include the role of texture, the development of autonomy, the optimization of variety, acceptable consumption levels of sweet and salty foods, and the way to cope with food refusal. Guidelines in general cover most of the themes, but some of the national guidelines are incomplete. Finally, guidelines should give more practical tips to parents, especially to help them establish a responsive feeding behaviour.

Variety is the spice of life: strategies for promoting fruit and vegetable acceptance during infancy.

The present manuscript describes two experimental studies that were conducted to explore the effects of an 8-day exposure to a particular food or a variety of foods between and/or within meals on fruit and vegetable acceptance in 74 infants. Whether the dietary experience modified acceptance depended on the flavors of foods experienced, whether the experience occurred between or within meals or both, and whether the target food was a fruit or vegetable. In the first study, we found that 8 days of dietary exposure to pears or a variety of fruits between meals (not including pears) resulted in greater consumption of pears by the infants but this increased acceptance did not generalize to green beans. In the second study, we found that 8 days of vegetable variety both between and within meals led to increased acceptance of green beans, carrots and spinach. Those infants who experienced green beans alone or a variety of vegetables between meals also tended to eat more green beans after the exposure. These findings suggest that not only can infants clearly discriminate flavors but repeated opportunities to taste a particular or a variety of foods may promote willingness to eat fruits and vegetables, the consumption of which is generally low in the pediatric population and the acceptance of which is difficult to enhance beyond toddlerhood.

Development of food variety in children.

Eating a variety of foods is essential to achieve adequate coverage of macro- and micronutrient needs. We expose here how eating habits for a variety of foods develop in childhood, from early infancy on. Preferences for specific flavours might develop early, through milk-related flavour exposures. Breastfeeding favours the acquisition of a taste for a variety of foods. At introduction of solid foods, food preferences develop thanks to repeated exposures to a variety of foods. The persistence of these early influences is still unknown. During the third year of life, most children enter a neophobic phase during which previously liked foods are no longer accepted and introduction of new foods becomes difficult. However, habits of eating a variety of foods acquired before the neophobic phase track further on into childhood, adolescence and early adulthood. This underlines the importance of promoting the access to a variety of foods in early childhood. However, beyond the nutritional advantage of eating a varied diet, could this present any drawbacks? Providing a variety of foods generally stimulates food intake and thereby might favour obesity. More research is needed to understand the link between variety and obesity, which might be food-group dependant.

Repetition counts: repeated exposure increases intake of a novel vegetable in UK pre-school children compared to flavour-flavour and flavour-nutrient learning

Children are not consuming sufficient amounts of fruits and vegetables in their habitual diet. Methods derived from associative learning theories could be effective at promoting vegetable intake in pre-school children. The objective of the present study was to compare the effectiveness of different learning strategies in promoting the intake of a novel vegetable. Children aged between 9 and 38 months were recruited from UK nurseries. The children (n 72) were randomly assigned to one of three conditions (repeated exposure, flavour-flavour learning or flavour-nutrient learning). Each child was offered ten exposures to their respective version of a novel vegetable (artichoke). Pre- and post-intervention measures of artichoke purée and carrot purée (control vegetable) intake were taken. At pre-intervention, carrot intake was significantly higher than artichoke intake (P<0·05). Intake of both vegetables increased over time (P<0·001); however, when changes in intake were investigated, artichoke intake increased significantly more than carrot intake (P<0·001). Artichoke intake increased to the same extent in all three conditions, and this effect was persistent up to 5 weeks post-intervention. Five exposures were sufficient to increase intake compared to the first exposure (P<0·001). Repeated exposure to three variants of a novel vegetable was sufficient to increase intake of this vegetable, regardless of the addition of a familiar taste or energy. Repetition is therefore a critical factor for promoting novel vegetable intake in pre-school children.

Variability of human saliva composition: Possible relationships with fat perception and liking

Saliva is the medium that bathes the taste receptors in the oral cavity and in which aroma and taste compounds are released when food is eaten. Moreover saliva contains enzymes and molecules that can interact with food. To date, little research has been devoted to the intra- and inter-individual variabilities of these components and their inter-relationships. The first aim of this work was to study intra- and inter-individual variabilities over time in the composition of molecules likely to interact with food in the mouth, with particular focus on molecules that might interact with fat. The second aim was to try to relate this composition to a liking for fat and its perception. Stimulated and unstimulated saliva from 13 subjects was collected in the morning and afternoon on three occasions at 4-month intervals. Saliva characteristics such as flow, protein concentration, lipolysis, proteolysis, amylolysis, lipocalin concentration, lysozyme activity, total antioxidant status and uric acid concentrations were measured, as well as the liking for and perceived fattiness of a fat solution. The results showed that for most of the measured characteristics, intra-subject variability in saliva composition was smaller than inter-subject variability, with remarkable stability over time (8 months) in terms of flow, lypolysis, proteolysis and total antioxidant status. Relationships were found between some of these characteristics (lipolysis, lipocalin and flow) and fat-liking or perception, showing that the composition of saliva may play an important role in fat perception and liking.

Learning to Eat Vegetables in Early Life: The Role of Timing, Age and Individual Eating Traits

Vegetable intake is generally low among children, who appear to be especially fussy during the pre-school years. Repeated exposure is known to enhance intake of a novel vegetable in early life but individual differences in response to familiarisation have emerged from recent studies. In order to understand the factors which predict different responses to repeated exposure, data from the same experiment conducted in three groups of children from three countries (n = 332) aged 4–38 m (18.9±9.9 m) were combined and modelled. During the intervention period each child was given between 5 and 10 exposures to a novel vegetable (artichoke puree) in one of three versions (basic, sweet or added energy). Intake of basic artichoke puree was measured both before and after the exposure period. Overall, younger children consumed more artichoke than older children. Four distinct patterns of eating behaviour during the exposure period were defined. Most children were “learners” (40%) who increased intake over time. 21% consumed more than 75% of what was offered each time and were labelled “plate-clearers”. 16% were considered “non-eaters” eating less than 10 g by the 5th exposure and the remainder were classified as “others” (23%) since their pattern was highly variable. Age was a significant predictor of eating pattern, with older pre-school children more likely to be non-eaters. Plate-clearers had higher enjoyment of food and lower satiety responsiveness than non-eaters who scored highest on food fussiness. Children in the added energy condition showed the smallest change in intake over time, compared to those in the basic or sweetened artichoke condition. Clearly whilst repeated exposure familiarises children with a novel food, alternative strategies that focus on encouraging initial tastes of the target food might be needed for the fussier and older pre-school children.

Food choices at lunch during the third year of life: high selection of animal and starchy foods but avoidance of vegetables.

AIM The objective was to show patterns of food selection by 2- to 3-y-old children for a wide variety of foods in a self-service cafeteria and to assess the effect of individual variables (gender, BMI, mode of feeding after birth and rank in sibship). METHODS In a nursery self-service canteen, food choices at lunch made by children (n=418, 24-36 mo; 109 observations per child on average) were recorded by trained assistants who monitored portion size. An offer of eight dishes (animal products, starchy foods, combination dishes, vegetables and dairy products), excluding dessert-type foods, was proposed. Choice level was calculated for each food. Analysis of variance was used to compare choices for the various foods and to assess the effect of the individual variables. RESULTS The choice of a food largely depended upon its nature: animal products, starchy foods and their combinations were widely chosen, whereas vegetables were not often selected; the choice for dairy products depended upon the type. The mode of preparation of the food influenced its choice. Segmenting products were identified; however, except for cheeses, a given child did not refuse an entire food category. Childrens characteristics did not explain the choice variability. CONCLUSION At the age of 2 to 3 y, children preferentially choose animal products and starchy foods and avoid vegetables; the high individual variability of their food choices could be related to previous food experiences.

Children's acceptance of new foods at weaning. Role of practices of weaning and of food sensory properties.

Weaning (i.e. introduction of complementary foods) is a transitional process between the consumption of a unique food, milk, and family foods. This review of existing literature regarding factors favouring the development of food acceptance at the beginning of weaning underlines in particular the roles of repeated exposure, of introduction of a variety of foods, of timing of introduction of weaning foods, and of food sensory properties (texture, taste and flavours). All factors appear to play a role in the acceptance of weaning foods. The efficiency, most favourable windows and long-term impact of each of these factors is not known accurately.

Determination and gustatory properties of taste-active compounds in tomato juice

The water-soluble compounds of a tomato juice selected for its high taste intensity and quality, have been investigated by both physico-chemical and sensory analyses. The physico-chemical assessment of the crude juice led to the construction of a synthetic model juice. Although 97% of the material contained in the crude juice has been identified and quantified, significant sensory differences between the crude and model juice have been found concerning bitterness and sharpness, showing that the components responsible for these gustatory descriptors have not yet been identified in the juice. For the other descriptors: sweetness, saltiness, sourness, umami and astringency, no significant differences were found between these two solutions. Using the model juice, omission tests were performed to explain the three main tastes of the juice: saltiness, sweetness and sourness. Sweetness was mainly attributable to sugars while the non-dissociated and dissociated forms of the organic acids, with potassium as counterion, seemed mainly responsible for sourness and saltiness. Moreover, several masking effects were observed between taste-active components. The contribution of the taste-active compounds to the main tastes were quantified by stepwise multiple linear regressions. The model explained up to 95, 89.9 and 85.8% of sourness, saltiness and sweetness, respectively.