Sara M. Ahern

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.

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.

Vegetables by stealth. An exploratory study investigating the introduction of vegetables in the weaning period

Few studies have examined in detail weaning practices and how mothers introduce vegetables into the diets of their infants. The current exploratory study set out to use both qualitative and quantitative methods to investigate approaches to nutrition in the weaning period and in early infancy with a particular focus on vegetables. 75 mothers of infants aged 24-72 weeks filled out a postal questionnaire regarding infant feeding during the weaning period. Mothers completed the infant feeding questionnaire (IFQ) and a food frequency questionnaire (FFQ) to measure familial fruit and vegetable intake. Mothers introduced solid food to their infants at around 20 weeks of age and those who breast-fed their infants tended to introduce solid foods later compared to formula feeding mothers (21 wks versus 17.8 wks, p<0.05). Infants were offered around 3 different types of vegetable during the first 4 weeks of weaning. 13 mothers then took part in a follow-up in-depth interview. Mothers reported that they relied upon advice from family and friends and their interpretation of cues from their infants indicating the readiness for food, rather than relying on official guidelines. Mothers demonstrated high concern about the nutrient quality of their childs diet and perceived vegetables to be an integral part of the diet. A number of strategies for promoting vegetable intake were identified by mothers, offering vegetables by stealth was one of the most commonly identified strategies.

The root of the problem: increasing root vegetable intake in preschool children by repeated exposure and flavour flavour learning.

Childrens vegetable consumption falls below current recommendations, highlighting the need to identify strategies that can successfully promote intake. The current study aimed to investigate the effectiveness of flavour-flavour learning as one such strategy for increasing vegetable intake in preschool children. Children (N = 29) aged 15 to 56 months were recruited through participating nurseries. Each received a minimum of six and maximium eight exposures to a root vegetable puree with added apple puree (flavour-flavour learning) alternating with six to eight exposures to another with nothing added (repeated exposure). A third puree acted as a control. Pre- and post-intervention intake measures of the three purees with nothing added were taken to assess change in intake. Follow-up measures took place 1 month (n = 28) and 6 months (n = 10) post-intervention. Intake increased significantly from pre- to post-intervention for all purees (~36 g), with no effect of condition. Magnitude of change was smaller in the control condition. Analysis of follow-up data showed that intake remained significantly higher than baseline 1 month (p < 0.001) and 6 months (p < 0.001) post-intervention for all conditions. Children under 24 months ate consistently more across the intervention than the older children (≥24 m) with no differences found in response to condition. This study confirms previous observations that repeated exposure increases intake of a novel vegetable in young children. Results also suggest that mere exposure (to the food, the experimenters, the procedure) can generalise to other, similar vegetables but the addition of a familiar flavour confers no added advantage above mere exposure.

Eating a rainbow. Introducing vegetables in the first years of life in 3 European countries.

Low vegetable consumption in children is a concern in many EU countries, fewer than one fifth of children in Europe consume the WHO recommended amounts. Systematic studies demonstrate that experience with a variety of vegetables early in childhood can promote later consumption as early dietary habits often track into adulthood. This study examined pre-school childrens experience with vegetables across three European countries in order to assess cultural differences, effects of age and culinary practices. Mothers of pre-school children (N=234) in the UK (N=71), Denmark (N=93) and France (N=70) completed a survey assessing parental and infant familiarity, frequency of offering and liking for 56 vegetables as well as preparation techniques for these vegetables. Analyses revealed that although children aged 25-36 months had been introduced to the greatest number of vegetables, children aged 6-12 months were offered vegetables more frequently and had a higher reported liking for these vegetables. UK childrens liking was related to frequency of maternal intake and frequency of offering. Denmark had introduced the greatest number of vegetables and offered vegetables more frequently than both the UK and France. Choice of preparation methods differed between countries while choice of seasonings was similar. Results suggest increasing variety and frequency of vegetable offering between 6 and 12 months, when children are most receptive, may promote vegetable consumption in children.

The effects of repeated exposure and variety on vegetable intake in pre-school children

Childrens vegetable consumption in the UK remains lower than national recommendations, presenting potential long-term health risks. It is known that repeated exposure promotes intake of novel vegetables and that offering children variety and choice can also encourage intake. The current study aimed to compare the impact of offering variety over simple repeated exposure as a strategy for increasing pre-school childrens vegetable consumption. Children (N = 95) aged 24-55 months were recruited through participating nurseries and assigned to receive repeated exposure (RE) to a single vegetable snack or a mixed snack consisting of five different vegetables (variety: V). A minimum of 5 (maximum 6) exposures were given for both RE and V conditions. Pre and post-intervention intake measures of both the RE and V snacks were taken for each child. Follow up measures took place 1 month post-intervention (n = 40). Vegetable intake increased significantly from pre to post intervention for snacks congruent to the condition to which children were assigned. Magnitude of change was smaller for the variety condition. Follow up data revealed that snack intake remained significantly higher than baseline 1 month post-intervention (p < 0.001). In agreement with previous work this study confirmed that repeated exposure was effective in promoting childrens vegetable intake but there was no additional benefit of variety in this context. It may be that for moderately familiar vegetables, serving them alone encourages intake and for this age group, avoids contamination fears or effects of neophobia.