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

Background

Not eating enough fruit and vegetables is a considerable health burden in developed countries. Eating adequate amounts of fruit and vegetables is associated with a reduced risk of future non-communicable diseases (such as cardiovascular disease). Early childhood represents a critical period for the establishment of dietary habits that track into adulthood. Interventions to increase consumption of fruit and vegetables in early childhood may therefore be an effective strategy to reduce 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 trials. 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) of interventions aiming to increase the intake of fruit or vegetables or both by children aged five years and under that measured intake was eligible. Two review authors independently searched for and extracted information from trials. The evidence is current to August 2019.

Results

We included 78 trials with 13,746 people taking part. Forty-eight trials examined child-feeding practice interventions (e.g. repeated exposure to vegetables), 15 examined parent nutrition education interventions, 14 examined multicomponent interventions (e.g. combining preschool policy changes with parent education), two examined child nutrition education interventions and one examined a child-focused mindfulness intervention. Child-feeding practice interventions may lead to, and multicomponent interventions probably lead to, small increases in children's intake of fruit and vegetables in the short term (less than 12 months). It is uncertain whether parent nutrition education interventions are 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. Trials reporting funding support received governmental or charitable funds, except for four trials that received industry funding.

Conclusions

Child-feeding practices may increase fruit and vegetable intake by children (by 4.45 g per day), however this conclusion is based on very-low quality evidence and is very likely to change when future research is undertaken. Multicomponent interventions probably increase fruit and vegetable intake by children (by 0.36 cups per day) based on the moderate quality of the evidence, however this may also change when future research is undertaken. It is uncertain whether parent nutrition education interventions increase children's fruit and vegetable intake.

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 78 eligible trials of various intervention approaches, the evidence for how to increase children's fruit and vegetable consumption remains limited. There was very low-quality evidence that child-feeding practice may lead to, and moderate-quality evidence that multicomponent interventions probably lead to small increases in fruit and vegetable consumption in children aged five years and younger. It is uncertain whether parent nutrition education interventions are effective in increasing fruit and vegetable consumption in children aged five years and younger. Given that the quality of the evidence is very low or low, future research will likely change estimates and conclusions. Long-term follow-up of at least 12 months is required and future 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 non-communicable diseases, including cardiovascular disease. Interventions to increase consumption of fruit and vegetables, such as those focused on specific child-feeding strategies and parent nutrition education interventions in early childhood may therefore be an effective strategy in reducing this disease burden.

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 CENTRAL, MEDLINE, Embase and two clinical trials registries to identify eligible trials on 25 August 2019. We searched Proquest Dissertations and Theses in May 2019. We reviewed reference lists of included trials and handsearched three international nutrition journals. We contacted authors of included trials 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 trials; 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 78 trials with 214 trial arms and 13,746 participants. Forty-eight trials examined the impact of child-feeding practices (e.g. repeated food exposure) in increasing child vegetable intake. Fifteen trials examined the impact of parent nutrition education in increasing child fruit and vegetable intake. Fourteen trials examined the impact of multicomponent interventions (e.g. parent nutrition education and preschool policy changes) in increasing child fruit and vegetable intake. Two trials examined the effect of a nutrition education intervention delivered to children in increasing child fruit and vegetable intake. One trial examined the impact of a child-focused mindfulness intervention in increasing vegetable intake.

We judged 20 of the 78 included trials 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 for the remaining trials.

There is very low-quality evidence that child-feeding practices versus no intervention may have a small positive effect on child vegetable consumption equivalent to an increase of 4.45 g as-desired consumption of vegetables (SMD 0.42, 95% CI 0.23 to 0.60; 18 trials, 2004 participants; mean post-intervention follow-up = 8.2 weeks). Multicomponent interventions versus no intervention has a small effect on child consumption of fruit and vegetables (SMD 0.34, 95% CI 0.10 to 0.57; 9 trials, 3022 participants; moderate-quality evidence; mean post-intervention follow-up = 5.4 weeks), equivalent to an increase of 0.36 cups of fruit and vegetables per day. It is uncertain whether there are any short-term differences in child consumption of fruit and vegetables in meta-analyses of trials examining parent nutrition education versus no intervention (SMD 0.12, 95% CI −0.03 to 0.28; 11 trials, 3078 participants; very low-quality evidence; mean post-intervention follow-up = 13.2 weeks). We were unable to pool child nutrition education interventions in meta-analysis; both trials reported a positive intervention effect on child consumption of fruit and vegetables (low-quality evidence).

Very few trials reported long-term effectiveness (6 trials), cost effectiveness (1 trial) and unintended adverse consequences of interventions (2 trials), limiting their assessment. Trials reported receiving governmental or charitable funds, except for four trials reporting industry funding.

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