N° 19 | January 2008

Ethnic differences in one-year follow-up effect of the Dutch Schoolgruiten Project-promoting fruit and vegetable consumption among primary schoolchildren

Introduction

In many western countries, including the Netherlands, children often do not comply with dietary recommendations. Notably, fruit and vegetable (F&V) intakes are lower than national guidelines1. The Dutch recommendation for F&V intake for 10-12-year-old children is 2 pieces of fruit and 150-200 grams vegetables per day2.

In the Netherlands, the Schoolgruiten (a Dutch acronym for ‘school fruits and vegetables’) Project was developed to promote adherence to the recommendations.

The Schoolgruiten Project targeted availability and accessibility of F&V at school through a F&V scheme. The children in the intervention group received a piece of fruit or ready-to-eat vegetables for free twice a week. Furthermore, this F&V scheme was supposed to increase the children’s exposure to F&V. Repeated exposure is an important determinant of taste preferences3.

In the Netherlands, especially in the major cities in the western part of the country, a growing minority, in some cities up to 50% of the children, has a non-Western background. For example, at least one of their parents was born in Morocco, Turkey, Surinam or the Netherlands Antilles. Evidence suggests that these children have different eating patterns, including different F&V intakes than children of Dutch ethnicity4. Since some of these minority groups have higher mean F&V intake levels, it might be expected that the intervention is less effective in these groups. The aim of the present study was to evaluate the one-year follow-up effect of the Schoolgruiten Project regarding F&V intake and potential determinants of F&V intake5-9 i.e. knowledge of recommendation, taste preferences, availability and accessibility. This was done separately for children of Dutch and of non-Western ethnicity.

We hypothesized that the intervention had a significant effect on F&V intakes and that the intervention was less effective among the children of non-Western ethnicity compared to ethnic Dutch children.

Methods

The design of this study was quasi experimental, with a pre- and posttest, and an intervention and control group.

Separate questionnaires for children and their parents were developed, both based on the validated Pro Children questionnaires10. Participating schoolchildren (mean age 9.9 years at baseline) and their parents completed the questionnaires at baseline and one year later, including questions on the child’s usual F&V intake, potential determinants, and general demographics, allowing evaluation based on child as well as parent-reports. Multi-level regression analyses were used to assess differences at follow-up between the control and intervention group, adjusted for gender, child’s age, educational level of the parents, and F&V baseline values.

Reports were available for 565 (232 interventions and 333 controls) children of Dutch ethnicity and 388 children (268 interventions and 120 controls) of non-Western ethnicity, and their parents.

Results

The majority (59%) of the children were of Dutch ethnicity. At baseline, the total sample of children of Dutch ethnicity reported a fruit intake of 1.58 (SD=1.06) pieces per day and a mean vegetable intake of 97.9 (SD=44.3) gram per day. After adjustments for the potential confounders, it appeared that the intervention group had significantly higher fruit intake than the controls according to the child-reports (difference=0.23 pieces per day, 95% CI=0.07–0.39).

The total sample of children of non-Western ethnicity reported a mean fruit intake of 2.02 (SD=1.17) pieces and a mean vegetable intake of 120.6 (SD=66.3) grams per day at baseline. At follow-up the children in the intervention group reported a significantly higher adjusted vegetable intake than the children in the control group (difference=20.7 gram per day, 95%CI=7.6-33.7).

Significant positive intervention effects were also found for perceived accessibility among children of non-Western ethnicity, and for parentreported taste preference of their child among children of non-Western ethnicity and among boys of Dutch ethnicity.

Discussion and conclusion

The present study indicates that the Schoolgruiten Project had a significant effect on fruit intake of children of Dutch ethnicity and on vegetable intake of children of non-Western ethnicity, but these effects were only found in analyses based on the child-reported data. That results could not be confirmed in parent reported data might be due to power issues. In addition, parents did not observe their child during the main part of the project.

Our hypothesis that children of non-Western ethnicity would profit less from the intervention, was only supported in case of fruit intake, but not for vegetable intake. Furthermore, differences according to ethnic background could not be explained by educational levels of the parents. In conclusion, providing ready-to-eat fruit and vegetables at school seems a promising intervention strategy promoting FV intake among primary schoolchildren.

1 Yngve A, Wolf A, Poortvliet E, Elmadfa I, Brug J, Ehrenblad B et al. Fruit and
vegetable intake in a sample of 11-year-old children in 9 European countries:
the Pro Children cross-sectional survey. Ann Nutr Metab 2005; 49:236-245
2 Anonymous. Zo eet Nederland (This is how the Dutch eat). Den Haag:
Voedingscentrum; 1998.
3 Wardle J, Herrera ML, Cooke L, Gibson EL. Modifying children’s food prefe
rences: the effects of exposure and reward on acceptance of an unfamiliar vege
table. Eur J Clin Nutr 2003; 57(2):341-348.
4 te Velde SJ, Wind M, Van Lenthe FJ, Klepp KI, Brug J. Differences in fruit and
vegetable intake and determinants of intakes between children of Dutch origin
and non-Western ethnic minority children in the Netherlands – a cross sectional
study. Int J Behav Nutr Phys Act 2006; 3(31).
5 Bere E, Klepp KI. Correlates of fruit and vegetable intake among Norwegian
schoolchildren: parental and self-reports. Public Health Nutr 2004; 7:991-998.
6 Bere E, Klepp KI. Reliability of parental and self-reported determinants of fruit
and vegetable intake among 6th graders. Public Health Nutr 2004; 7:353-356.
7 Wind M, De Bourdeaudhuij I, te Velde SJ, Sandvik C, Klepp KI, Due P et al.
Correlates of fruit and vegetable consumption among 11-year-old Belgian-
Flemish and Dutch schoolchildren. J Nutr Educ Behav 2006; 38(4):211-221.
8 De Bourdeaudhuij I, te Velde SJ, Brug J, Due P, Wind M, Sandvik C et al.
Personal, social and environmental predictors of daily fruit and vegetable intake
in 11-year-old children in nine European countries. Eur J Clin Nutr 2007;advan
ce online publication 16 May 2007; doi: 10.1038/sj.ejcn.1602794.
9 Blanchette L, Brug J. Determinants of fruit and vegetable consumption among
6-12-year-old children and effective interventions to increase consumption. J
Hum Nutr Dietet 2005; 18(6):431-443.
10 Haraldsdottir J, Thorsdottir I, de Almeida MD, Maes L, Perez Rodrigo C, Elmadfa
I et al. Validity and reproducibility of a precoded questionnaire to assess fruit
and vegetable intake in European 11- to 12-year-old schoolchildren. Ann Nutr
Metab 2005; 49(4):221-227.

Return