Interventions for increasing eating of fruit and vegetables in children aged five years and under

Background

Consuming not enough fruit and vegetables is a considerable health burden in developed countries. Eating fruit and vegetables is associated with a reduced risk of future chronic disease. Early childhood represents a critical period for the establishment of dietary habits. Interventions to increase consumption of fruit and vegetables in early childhood may therefore be an effective strategy in reducing this disease burden.

Review question

To assess the impact of interventions designed to increase eating of fruit or vegetables or both among children aged five years and under.

Methods

We searched various electronic databases and relevant journals to find studies. We contacted authors of included trials for additional potentially relevant trials. Any randomised trial (participants have the same chance of being assigned to treatment or control) was eligible of interventions aiming to increase the intake of fruit or vegetables or both by children aged five years and under that measured intake. Two review authors independently searched for and extracted information from studies. The evidence is current to September 2016.

Results

We include 50 trials with 10,267 people taking part. Thirty examined child-feeding interventions, 11 examined parent nutrition education interventions, eight examined multicomponent interventions and one examined a child nutrition education intervention. Child-feeding interventions (e.g. repeated exposure to vegetables) were effective in increasing children's intake of vegetables in the short term (less than 12 months). Parent nutrition education and multicomponent interventions (e.g. combining preschool policy changes with parent education) were not effective in increasing children's eating of fruit and vegetables. There was not enough information to assess long-term effectiveness, cost effectiveness and unintended harms. Studies reporting funding support received governmental or charitable funds, except for two studies that received industry funding.

Conclusions

The evidence for effective interventions to increase eating of fruit and vegetables by children aged five and under remains sparse. Child-feeding interventions appear to increase the eating of vegetables by children (by 4.03 grams), but this conclusion is based on very low-quality evidence and is very likely to change when future research is undertaken.

This is a living systematic review. Living systematic reviews offer a new approach to review updating, in which the review is continually updated, incorporating relevant new evidence as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Authors' conclusions: 

Despite identifying 50 eligible trials of various intervention approaches, the evidence for how to increase fruit and vegetable consumption of children remains sparse. There was very low-quality evidence child-feeding practice interventions are effective in increasing vegetable consumption of children aged five years and younger, however the effect size was very small and long-term follow-up is required. There was very low-quality evidence that parent nutrition education and multicomponent interventions are not effective in increasing fruit and vegetable consumption of children aged five years and younger. All findings should be considered with caution, given most included trials could not be combined in meta-analyses. Given the very low-quality evidence, future research will very likely change estimates and conclusions. Such research should adopt more rigorous methods to advance the field.

This is a living systematic review. Living systematic reviews offer a new approach to review updating, in which the review is continually updated, incorporating relevant new evidence as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Read the full abstract...
Background: 

Insufficient consumption of fruits and vegetables in childhood increases the risk of future chronic diseases, including cardiovascular disease.

Objectives: 

To assess the effectiveness, cost effectiveness and associated adverse events of interventions designed to increase the consumption of fruit, vegetables or both amongst children aged five years and under.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE, Embase Classic and Embase to identify eligible trials on 30 September 2016. We searched CINAHL and PsycINFO in July 2016, Proquest Dissertations and Theses in November 2016 and three clinical trial registers in November 2016 and June 2017. We reviewed reference lists of included trials and handsearched three international nutrition journals. We contacted authors of included studies to identify further potentially relevant trials.

Selection criteria: 

We included randomised controlled trials, including cluster-randomised controlled trials and cross-over trials, of any intervention primarily targeting consumption of fruit, vegetables or both among children aged five years and under, and incorporating a dietary or biochemical assessment of fruit or vegetable consumption. Two review authors independently screened titles and abstracts of identified papers; a third review author resolved disagreements.

Data collection and analysis: 

Two review authors independently extracted data and assessed the risks of bias of included studies; a third review author resolved disagreements. Due to unexplained heterogeneity, we used random-effects models in meta-analyses for the primary review outcomes where we identified sufficient trials. We calculated standardised mean differences (SMDs) to account for the heterogeneity of fruit and vegetable consumption measures.We conducted assessments of risks of bias and evaluated the quality of evidence (GRADE approach) using Cochrane procedures.

Main results: 

We included 50 trials with 137 trial arms and 10,267 participants. Thirty trials examined the impact of child-feeding practices (e.g. repeated food exposure) in increasing child vegetable intake. Eleven trials examined the impact of parent nutrition education in increasing child fruit and vegetable intake. Eight studies examined the impact of multicomponent interventions (e.g. parent nutrition education and preschool policy changes) in increasing child fruit and vegetable intake. One study examined the effect of a nutrition intervention delivered to children in increasing child fruit and vegetable intake.

Thirteen of the 50 included trials were judged as free from high risks of bias across all domains; performance, detection and attrition bias were the most common domains judged at high risk of bias of remaining studies.

Meta-analysis of trials examining child-feeding practices versus no intervention revealed a positive effect on child vegetable consumption (SMD 0.38, 95% CI 0.15 to 0.61; n = 1509; 11 studies; very low-quality evidence), equivalent to a mean difference of 4.03 grams of vegetables. There were no short-term differences in child consumption of fruit and vegetables in meta-analyses of trials examining parent nutrition education versus no intervention (SMD 0.11, 95% CI -0.05 to 0.28; n = 3023; 10 studies; very low-quality evidence) or multicomponent interventions versus no intervention (SMD 0.28, 95% CI -0.06 to 0.63; n = 1861; 4 studies; very low-quality evidence).

Insufficient data were available to assess long-term effectiveness, cost effectiveness and unintended adverse consequences of interventions.Studies reported receiving governmental or charitable funds, except for two studies reporting industry funding.

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