Epidemiological evidence suggests that regular fruit and vegetable intake helps to promote health and prevent chronic disease(Reference Hu1–Reference Joshipura, Ascherio, Manson, Stampfer, Rimm, Speizer, Hennekens, Spiegelman and Willett3). The health benefits of fruits and vegetables seen in epidemiological studies are the main reason for the recommended intake of at least 400 g of fruits and vegetables per day(4). However, large population groups, particularly in northern Europe, eat far less than the recommended amount of fruits and vegetables.
The present study is a part of the Pro Children cross-Europe survey, involving nine European countries. The survey aims to assess fruit and vegetable consumption among 11-year-old schoolchildren and their parents, and to elucidate the potential determinants of consumption at the individual, social and environmental level(Reference Klepp, Perez-Rodrigo and De Bourdeaudhuij5, Reference Rasmussen, Krolner, Klepp, Lytle, Brug, Bere and Due6). Knowing the determinants of behaviour is necessary to develop an intervention. Insight into the determinants of fruit and vegetable consumption where intake is low can possibly be used to increase intake in low-intake population groups. An intervention aimed at increasing fruit and vegetable intake among children is likely to maximize health benefits, as healthy food habits acquired in childhood tend to continue into adulthood(Reference Lien, Lytle and Klepp7) and children are more apt to change their food habits than adults(Reference Birch and Fisher8, Reference Savage, Fisher and Birch9). Parents are determinants of the environment for young children; parent’s behaviour has therefore been an obvious area for attention(Reference Savage, Fisher and Birch9–Reference Faith, Berkowitz, Stallings, Kerns, Storey and Stunkard12). There are, however, only a few studies assessing child–parent agreement of the determinants of children’s food intake, especially their fruit and vegetable intake: a Norwegian study and two Dutch studies(Reference Bere and Klepp13–Reference Reinaerts, de Nooijer and de Vries15). In the Pro Children cross-Europe survey, children and parents were asked parallel questions on the environmental determinants of fruit and vegetable intake, making it possible to study differences in perception.
The results from the Pro Children cross-Europe survey showed that fruit and vegetable intake among children was lowest in Iceland(Reference Yngve, Wolf and Poortvliet16). Sixty-four per cent of Icelandic children ate fruit less than once per day, and 61 % ate vegetables less than once per day. Fruit and vegetable intake among mothers in Iceland was low(Reference Wolf, Yngve and Elmadfa17). Determinants of fruit and vegetable intake, based on children’s self-reports, have been studied. Respectively, 31 % and 39 % of the variance in children’s fruit intake and vegetable intake was explained by the determinants studied(Reference Kristjansdottir, Thorsdottir, De Bourdeaudhuij, Due, Wind and Klepp18). The major environmental determinants were availability at home, which was positively related to both fruit and vegetable intake, as was modelling and demand family rule, while active encouragement was negatively related to intake. Self-efficacy was the strongest personal determinant of fruit intake, followed by knowledge of recommendations, attitudes, preferences and liking. For vegetable intake, preferences and liking were the strongest personal determinants, followed by knowledge of recommendations and self-efficacy.
The present study focuses on determinants in the physical and the social environment, of which the parents are part, and which in turn influence the more proximal determinants found at the personal level. The objective of the present study was to study differences between children’s self-reports and parents’ reports on the physical and social environmental determinants of fruit and vegetable intake of children in Iceland. A second objective was to examine the observed variance in fruit and vegetable intake among the children.
Methods
Sample and procedure
A cross-sectional survey was performed in Iceland (in the autumn of 2003) as part of the Pro Children cross-Europe survey. A random national sample of thirty-three primary schools was selected from a list from Statistics Iceland. Research approval was obtained from the Icelandic Data Protection Authority. Approval to contact the schools was obtained from the Reykjavik School District Head Office and Service Centre. The headmasters of the schools were approached about their willingness to participate (thirty-two schools participated), and the class teachers were asked to collect the data using standardized instructions. Children in the sixth grade (born 1992) answered a self-administered questionnaire, with instructions and help from the teacher. The children were sent home with questionnaires for their parents. A total of 1235 children, and 981 parents, returned the questionnaire. All children and their parents received written information on the project. The parent–child pairs were identified through labelling of the otherwise anonymous questionnaires. The final sample consisted of 963 child–parent couples, 480 girls and 483 boys, 819 mothers and 93 fathers; fifty-one did not answer the question on the relationship to the child, or had a different relationship to the child other than being its mother or father.
Parents were asked about his/her and his/her partner’s education and occupation. These answers were used as an approximate measure of the family’s socio-economic status (SES), using the higher SES for the family. These answers were coded into five categories according to a standardized protocol with national adaptation, using the occupation-status list from Statistics Iceland (ISTARF 95).
Instrument
Self-administered questionnaires were developed for children and their parents to assess fruit and vegetable intake and identify the determinants of their fruit and vegetable intake. The dietary part of the questionnaire consisted of an FFQ with four questions on usual intake of fresh fruits, salad or grated vegetables, other raw vegetables and cooked vegetables. The answer categories ranged from never to more than twice per day on an 8-point scale. This dietary assessment showed high reliability and validity. The results have been presented elsewhere(Reference Haraldsdottir, Thorsdottir, de Almeida, Maes, Perez Rodrigo, Elmadfa and Frost Andersen19, Reference Kristjansdottir, Andersen, Haraldsdottir, de Almeida and Thorsdottir20).
An overview of the variables assessed, and the children’s and parents’ questions on determinants of fruit and vegetable consumption, is presented in Table 1. The determinant parts of the questionnaires and their reliability and validity have been presented elsewhere(Reference De Bourdeaudhuij, Klepp, Due, Rodrigo, de Almeida, Wind, Krolner, Sandvik and Brug21).
Table 1 Children’s and parents’ questions on the determinants of fruit and vegetable intake, an overview of the variables assessed. Parallel questions were asked on fruits (F) and vegetables (V); the labels on the response scales were similar for children and parents
The labels on the question were as follows. 1: Yes, always; Yes, most days/often; Sometimes; Seldom; Never. 2: I fully agree; I agree somewhat; Neither agree nor disagree; I disagree somewhat; I fully disagree. 3: Yes, he/she never eats F/V unprompted; Yes, sometimes; Almost never; No, he/she eats F/V often unprompted. 4: Very many F/V; Many F/V; Not many, not few; Few F/V; Very few F/V. 5: Yes, definitely; Yes, probably; No, probably not; No, definitely not. 6: No F/V; 1–3 times/week; 4–6 times/week; 1 time/d; 2 times/d; 3 times/d; 4 times/d; 5 times or more/d (re-coded to <2 times/d (0) or 2 times or more/d (1)).
Statistical analyses
The data were analysed using the SPSS statistical software package version 11 (SPSS Inc., Chicago, IL, USA). Repeated-measures ANOVA were executed with perception (child–parent) as the within-subject factor and the gender of the child (boy–girl) as the between-subjects factor for each of the variables. The main effect of perception shows whether there are significant differences between the perceptions of the child and the parent; the main effect of gender shows whether there are differences in perceptions between boys and girls (combining responses of parents and children); and the interaction effect shows whether the differences in perceptions between children and parents depend on the gender of the child. The significance level was set at P < 0·01. The study had power to detect a difference of 0·25 points, on a 5-point scale, at 88·8 % power. Hierarchical regression analyses were performed to determine the explained variance of the children’s fruit and vegetable intake.
Results
The correlation coefficients between a child’s and its parent’s fruit and vegetable intake, based on the FFQ, were low. For fruit the correlation coefficient was 0·21 (P < 0·01), for vegetables 0·17 (P < 0·02) and for fruit and vegetables combined 0·24 (P < 0·01).
Children’s and parents’ perceptions – fruit
Differences were found between children’s and parents’ reports for most of the determinants of fruit intake (Table 2). Parents reported more positively on availability and accessibility of fruits at home than did their children. Children reported more modelling, more active encouragement, more demand and considered eating fruit every day more a habit than their parents. Girls and their parents reported more positively on availability of specific fruits than did boys and their parents. In addition, boys and their parents rated their fruit intake as lower and also reported fruit intake to be less a habit than did girls and their parents. Parents of boys reported more encouragement and demand than parents of girls, while boys and girls reported similar encouragement and demands to eat fruit from their parents.
Table 2 Children’s and parents’ perceptions of the determinants of fruit intake (947 child–parent couples), potential range, mean values with their standard errors, and results of repeated-measure ANOVA detailing the difference between the perception of the child and the parent, the difference between boys and girls and the interaction between the child’s perception and gender: Pro Children cross-Europe survey among 11-year-old children and their parents, Iceland, 2003
Children’s and parents’ perceptions – vegetables
Differences between children’s and their parents’ reports were found for most of the determinants of vegetable intake (Table 3). Children reported more positively on availability of specific vegetables than their parents. Children reported more active encouragement and more demands to eat vegetables than did their parents; children rated their vegetable intake as greater and reported the recommendation more accurately than their parents. Parents reported more positively that their children were allowed to eat vegetables as much as they liked. Girls and their parents rated their intake greater than did boys and their parents. Girls reported eating vegetables more often with their family than did boys, girls also reported more allowing rules, while the parents of girls and boys reported similarly on these determinants. Mothers of boys reported more encouragement than mothers of girls, while girls and boys reported similar encouragement.
Table 3 Children’s and parents’ perceptions of the determinants of vegetable intake (942 child–parent couples), potential range, mean values and their standard errors, and results of repeated-measure ANOVA detailing the difference between the perception of the child and the parent, the difference between boys and girls and the interaction between the child’s perception and gender: Pro Children cross-Europe survey among 11-year-old children and their parents, Iceland, 2003
Hierarchical regression model – fruit
Parents’ reports of the assessed determinants did not explain the variance in children’s fruit intake as strongly as the children’s own reports, 9 % and 18 %, respectively (Tables 4 and 5). When looking at the parents’ reports, availability at home and accessibility were positively related to children’s fruit intake but became non-significant in later steps of the model. Active encouragement was negatively related to intake. When looking at the children’s reports, gender was significant but became non-significant in later steps of the model. The availability at home reported by the children was positively related to fruit intake. Modelling of fathers (i.e. father eats fruit every day) and demanding family rule were both positively related to fruit intake. Children’s knowledge of recommendations was also positively related to fruit intake.
Table 4 Hierarchical regression model explaining the variance in children’s fruit intake, parents’ questionnaire (n 697): Pro Children cross-Europe survey among 11-year-old children and their parents, Iceland, 2003
SES, socio-economic status.
Table 5 Hierarchical regression model explaining the variance in children’s fruit intake, child’s questionnaire (n 745): Pro Children cross-Europe survey among 11-year-old children and their parents, Iceland, 2003
SES, socio-economic status.
Hierarchical regression model – vegetables
In general, the model explained more variance in vegetable than fruit intake, as with fruit intake more variance was explained by the children’s own reports than the parent’s. The variables assessed among parents explained 16 % of the variance of children’s vegetable intake (Table 6). The effect of gender and SES of the family were significant, with girls eating more vegetables than boys and children in families of high SES eating more vegetables than children in families of lower SES. Accessibility was positively related to children’s vegetable intake but became non-significant in later steps of the model. Active encouragement was negatively related to intake. When looking at the children’s reports, the regression model explained 37 % of children’s vegetable intake (Table 7). The effect of gender and SES of the family were significant, with girls eating more vegetables than boys and children in families of high SES eating more vegetables than children in families of low SES. The availability at home was positively related to vegetable intake. Eating vegetables together and demanding family rule were both positively related to vegetable intake. Children’s knowledge of recommendations was also positively related to vegetable intake.
Table 6 Hierarchical regression model explaining the variance in children’s vegetable intake, parents’ questionnaire (n 664): Pro Children cross-Europe survey among 11-year-old children and their parents, Iceland, 2003
SES, socio-economic status.
Table 7 Hierarchical regression model explaining the variance in children’s vegetable intake, child’s questionnaire (n 770): Pro Children cross-Europe survey among 11-year-old children and their parents, Iceland, 2003
SES, socio-economic status.
Discussion
Differences were found between children’s self-reports and parents’ reports on the environmental determinants of fruit and vegetable intake of the children in the Icelandic part of the Pro Children survey. A larger proportion of the observed variance in children’s fruit and vegetable intake could be explained by the children’s reports than by the parent’s. The strongest determinants for fruit and vegetable intake according to the children’s reports were availability at home, modelling, demanding family rule and knowledge of recommendations. The strongest modelling determinant for fruit was the father’s fruit intake while for vegetables it was eating vegetables together with the family. The background variables, gender and SES, seemed to be more important determinants of vegetable intake than of fruit intake.
Parents are very likely the most important models for their children; however, there was a low correlation between parent’s and child’s fruit and vegetable intake. This has been found in other studies, e.g. in a Norwegian study of children of similar age range where the correlation between the children’s and their parents’ fruit and vegetable intake was 0·23(Reference Bere and Klepp13). The low correlations that have been found between food preferences of parents and children have been referred to as the ‘family paradox’(Reference Rozin22, Reference Eertmans, Baeyens and Van den Bergh23). It may indicate that other determinants are stronger than parents’ intake or preference. A type of family influence that has received increasing research attention in recent years is the influence that parents may have on their children’s dietary behaviour through food-related parenting practices(Reference Wardle, Carnell and Cooke11, Reference Birch and Fisher24). Children may perceive some of the determinants differently from the parents and data obtained both from children and parents make it possible to obtain these ‘perceptional biases’.
The Icelandic parents reported greater availability and accessibility of fruits at home than their children. This is consistent with previous studies such as the Norwegian study by Bere and Klepp(Reference Bere and Klepp13) and the Dutch study by Reinaerts et al.(Reference Reinaerts, de Nooijer and de Vries15), where parents reported the availability or accessibility of fruits and vegetables as much greater than did their 10–12-year-old children. Reports of children and parents were more in agreement for vegetables, maybe because they are more often eaten as part of meals served by parents. Availability is one of the determinants most consistently related to intake(Reference Rasmussen, Krolner, Klepp, Lytle, Brug, Bere and Due6, Reference Blanchette and Brug25). In the present study, availability of different kinds of fruits and vegetables at home, as reported by the children, was a significant determinant of intake. Availability may be a more significant determinant of intake where intake is low. A comparison of the nine countries in the Pro Children survey showed that the availability of vegetables was significant for vegetable intake of the Icelandic children, while it was non-significant in the other countries where the intake was higher(Reference De Bourdeaudhuij, Te Velde and Brug26). Comparison of the nine countries in the Pro Children survey showed almost no country differences in the proportion of children reporting fruit to be available at home, except for Icelandic boys, who reported fruit availability to be lower(Reference Sandvik, De Bourdeaudhuij and Due27). The same tendency, although not significant, was seen for the availability at home of vegetables. Availability at school of both fruit and vegetables was also very low in Iceland. Making fruits and vegetables more easily available to the children might increase their intake, as has been seen in a Norwegian free fruit school programme(Reference Bere, Veierod and Klepp28–Reference Bere, Veierod, Skare and Klepp30).
Children rated their fruit and vegetable intake to be higher than did their parents, and they also reported more often than their parents that eating fruit was a habit for them. This is in line with the Dutch study of 9- to 10-year-old children and their parents by Tak et al.(Reference Tak, te Velde, de Vries and Brug14), who too found that children reported significantly higher intake levels of fruits and vegetables than their parents. The Dutch study by Reinaerts et al.(Reference Reinaerts, de Nooijer and de Vries15) also found that children reported higher vegetable intake than their parents; however, fruit intake was similarly reported. Parents of children at that age may not know very well what their children eat as they are at school for a large part of the day, or at clubs, or at friends’ houses, and also eat when parents do not see it. From this perspective children’s reports of fruit and vegetable intake could be considered more accurate than their parents’ reports. The higher intake levels reported by children than by parents in the present study are in contrast with the tentative idea that parents may express more social desirability than children in general. Some previous family studies have found that parents have higher social desirability than children because they may want to demonstrate ‘good’ parenting resulting in ‘healthy’ children(Reference De Bourdeaudhuij and Van Oost31). This pattern of social desirability biases in the responses between parents and children was not found in either the present study or the Dutch studies above(Reference Tak, te Velde, de Vries and Brug14, Reference Reinaerts, de Nooijer and de Vries15).
Our results on fruit and vegetable intake as well as on the determinants of the intake suggest that self-reports from 11-year-old children should be preferred above reports from their parents. It is necessary to take into account the ability of children of particular ages to report themselves. The development of an instrument has to take children’s abilities into account. As Livingstone and Robson argue, from the age of 8 years there is a rapid increase in the ability of children to self-report food intake(Reference Livingstone and Robson32). The accuracy of self-reports in young age groups is highly dependent on the complexity of the instrument used. The instrument used in the present study was developed so that it could be used by 11-year-old children to report themselves without parental assistance(Reference Haraldsdottir, Thorsdottir, de Almeida, Maes, Perez Rodrigo, Elmadfa and Frost Andersen19, Reference De Bourdeaudhuij, Klepp, Due, Rodrigo, de Almeida, Wind, Krolner, Sandvik and Brug21). The reliability of the 100-item questionnaire was highly acceptable for the Icelandic 11-year-olds, but clearly it might be demanding for younger children(Reference Haraldsdottir, Thorsdottir, de Almeida, Maes, Perez Rodrigo, Elmadfa and Frost Andersen19, Reference De Bourdeaudhuij, Klepp, Due, Rodrigo, de Almeida, Wind, Krolner, Sandvik and Brug21). As Livingstone and Robson suggest, future research should focus on refining dietary survey methods to make them more sensitive to different ages and to look for techniques that are able to identify misreporters(Reference Livingstone and Robson32).
Clear gender differences in fruit and vegetable intake were found, with girls’ intake being more frequent than boys’. This is consistent with other European studies(Reference Rasmussen, Krolner, Klepp, Lytle, Brug, Bere and Due6). Girls also rated their fruit and vegetable intake higher, and they reported more often that eating fruit was a habit for them than did boys. This indicates that the perception children have of their own intake is fairly realistic, as more objective methods also show that girls’ intake tends to be higher than that of boys of the same age(Reference Glynn, Emmett and Rogers33).
Fathers seem to have stronger modelling effects on their children’s fruit intake than mothers. Fathers’ fruit intake reported by children was positively related to their fruit intake while the mothers’ fruit intake, as reported by their children, was non-significant. Studies (mainly answered by mothers) have shown a positive relationship between parents’ and children’s intake of fruits and vegetables(Reference Rasmussen, Krolner, Klepp, Lytle, Brug, Bere and Due6). There are few studies on the relationship between fathers’ fruit intake and their children’s. In an Icelandic study of 6-year-old children and their parents, vitamin C in blood showed an even stronger correlation between the children and fathers than between the children and mothers(Reference Thorsdottir, Gunnarsdottir, Ingolfsdottir and Palson34). It may also be that children eat fruits more often with their father than with their mother and it may therefore be related to eating together. Eating vegetables together as reported by the child was positively related to the child’s intake in the present study. Seeing others consume a food may produce a form of modelling or ‘exposure by proxy’ which could reduce rejection and increase acceptance(Reference Wardle, Herrera, Cooke and Gibson35).
Children reported more active encouragement and demanding rules from their parents to eat fruit and vegetables daily than did their parents. This may partly be because of a phrasing difference between the child and parent questions. Demand is a strong word, at least in Icelandic, and parents may hesitate to use it. This difference could, however, be partly explained by differences in perception; i.e. the parents do not see themselves as encouraging or demanding as their children do. Active encouragement as reported by parents was negatively related to both fruit and vegetable intake. The parent was asked ‘Do you have to persuade your child to eat fruits/vegetables?’ and it is probable that the parents of children with low fruit and vegetable intake are more likely to answer this question positively. Parents of boys reported more encouragement than parents of girls, which seems logical as boys have lower intake levels, and children’s low intake might evoke parental encouragement. However, girls and boys reported similar encouragement from their parents. Active encouragement reported by the child was non-significantly related to their fruit and vegetable intake. It is unclear whether active encouragement is an effective way to increase the intake. Children who have low vegetable intake may always have been difficult to feed and, despite a parent’s best intention, a child may act with the least desired response from the parent’s perspective when it is pressured to eat(Reference Wardle, Carnell and Cooke11, Reference Galloway, Fiorito, Francis and Birch36). Demanding family rule (reported by a child but not by the parent) seems to be a more effective way to increase intake, as it was positively related to both fruit and vegetable intake. In the cross-Europe survey the association between vegetable intake and demanding family rule was strongest in Iceland and in Norway (OR = 2·1)(Reference De Bourdeaudhuij, Te Velde and Brug26). The parents were asked further about the rules regarding vegetables, i.e. if their children were supposed to eat all/part/some of the vegetable with the meal, but none of these was significantly related to children’s vegetable intake. Presenting a child with vegetables to taste could be the most promising approach, so that the child tastes vegetables without pressure on how much is eaten. Studies have shown that mere exposure to food increases liking, but attempts to control intake reduce the strength of the exposure effect(Reference Galloway, Fiorito, Francis and Birch36). Wardle et al. suggested that repeatedly inviting children to eat small amounts of rejected or disliked food, without great emphasis on how much the child eats, is a good strategy for promoting the liking of vegetables(Reference Wardle, Cooke, Gibson, Sapochnik, Sheiham and Lawson37).
Children’s knowledge of national recommendations was positively related to their fruit and vegetable intake. The simple strategy of teaching these recommendations in elementary schools may be important to make daily intake more likely(Reference De Bourdeaudhuij, Te Velde and Brug26). Parents’ knowledge of recommendations was, however, non-significant, suggesting that parents’ knowledge is not enough although it could be the first step, and parents’ eating habits and feeding practices are more important determinants of their children’s fruit and vegetable intake.
The strength of the present study is the large and representative sample, with a high participation rate. The limitations of the study were that determinants were measured by one item only; however, some of the determinants support each other, e.g. self-rated intake and habit. There may also be a phrasing or semantic difference between the child and parent questions; e.g. in the question on demanding family rule, the parent’s question may be more authoritarian than the child’s questions. The data are self-reported; therefore, all measures are perceived measures, but thorough validity and reliability studies have shown that the measures were valid and reliable(Reference Haraldsdottir, Thorsdottir, de Almeida, Maes, Perez Rodrigo, Elmadfa and Frost Andersen19, Reference De Bourdeaudhuij, Klepp, Due, Rodrigo, de Almeida, Wind, Krolner, Sandvik and Brug21). As this was a cross-sectional study, it cannot express causality between the determinants and frequency of fruit and vegetable intake.
Conclusion
The present study shows that children and parents have different perceptions of the determinants of fruit and vegetable intake in a child population with low consumption. Children’s perceptions explain more of the variance in intake. Children rather than their parents should be asked what determines their fruit and vegetable intake. However, children reported determinants in the physical and social environment, of which the parents are part, as an important determinant for their intake. Interventions aiming to increase fruit and vegetable intake among children must therefore target the parents. Such interventions ought to focus on practical guidance on how parents can promote healthy food habits.
Acknowledgements
The authors have no competing interest. All authors are responsible for the reported research. A.G.K. worked on the statistical analysis, wrote the first draft of the manuscript and made the greatest contribution to the paper. K.-I.K. and I.D.B. participated in designing the study and project planning. I.D.B. participated in the data analysis. I.T. was the local project leader and participated in all parts of the work. All authors provided critical revision of the paper, and read and approved the final manuscript. The study was carried out with financial support from the Commission of the European Communities, specifically the RTD programme ‘Quality of Life and Management of Living Resources’, QLK1-2001-00547 ‘Promoting and Sustaining Health through Increased Vegetable and Fruit Consumption among European Schoolchildren’ (Pro Children). It does not necessarily reflect the views of the RTD programme and in no way anticipates the Commission’s future policy in this area. The Pro Children consortium consists of the following partners: Knut-Inge Klepp (Coordinator), Department of Nutrition, University of Oslo, Norway; Carmen Perez Rodrigo, Unidad de Nutricion Comunitaria, Bilbao, Spain; Inga Thorsdottir, Unit for Nutrition Research, Landspitali University Hospital, Reykjavik, Iceland; Pernille Due, Department of Social Medicine, University of Copenhagen, Denmark; Maria Daniel Vaz de Almeida, Faculdade de Ciências da Nutrição e Alimentação da Universidade do Porto, Portugal; Ibrahim Elmadfa, Institute of Nutrition, University of Vienna, Austria; Jóhanna Haraldsdóttir, Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Copenhagen, Denmark; Johannes Brug, Erasmus Medical Center Rotterdam, Department of Public Health, The Netherlands; Michael Sjöström, Unit for Preventive Nutrition, Karolinska Institutet, Stockholm, Sweden; Ilse De Bourdeaudhuij, Department of Movement and Sport Sciences, Ghent University, Belgium.
