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What are the effects of combining changes to the food environment and nutrition education, or either of these components alone, on children’s dietary intake-related behaviors?

Conclusion

Consistent evidence suggests that combining nutrition education with changes to the school food environment is more effective for improving children’s and adolescents’ dietary intake than making changes to the food environment alone.
 

Grade

I – Strong

 

Evidence Summary Overview

The studies included in this review provide evidence suggesting that combining changes to the school food environment with nutrition education is more effective for improving children and adolescent’s dietary intake than changing the food environment alone. All four studies comparing “nutrition education combined with changes to the school food environment” to “changes to the school food environment alone” found some evidence that combining nutrition education with changes to the school food environment improved dietary intake more than only making changes to the school food environment. It is important to note that in two of these studies, the direct comparison between the combination intervention and the food environment intervention did not differ significantly, though the combination intervention led to improvements compared to control while the food environment alone intervention did not. The study that compared “nutrition education combined with changes to the school food environment” to “nutrition education alone” found some evidence that combining nutrition education with changes to the school food environment improved dietary intake more than only providing nutrition education. However, the study had mixed results, with some differences that were based on gender.

Description of the Evidence

The literature search for studies that tested the effects of nutrition education combined with changes to the food environment identified 3,538 articles, 432 of which were selected for review (Figure 4-D.1). Of these 432 articles, three were selected for inclusion in the systematic review. In addition, two articles were identified via hand search. Therefore, this systematic review includes a total of five articles. A detailed description of literature search results, including the databases searched and the number of articles identified using each database, articles identified using hand search, a list of citations for all included articles, and a table that lists excluded studies with rationale for exclusion can be found in Appendix G.

Click Figure 4-D.1. to see Flow chart of literature search results for Studies Examining the Effects of Nutrition Education Combined with Changes to the Food Environment.

Of the five studies included in this review, three were randomized controlled trials (RCT) [Birnbaum, 2002 (positive quality); He, 2009 (neutral quality); Prell, 2005 (neutral quality)] and two were non-randomized controlled trials [Ask, 2001 (neutral quality); Horne, 2004 (positive quality)]. Three studies received a neutral quality rating and two studies received a positive quality rating.

Studies were conducted in Canada, Norway, Sweden, the United Kingdom, and the United States (US). Sample sizes of these studies ranged from 54 to 3,503. All five studies included both boys and girls. Mean subject age ranged from 12 years to 15 years; two studies did not report mean age, one of which was conducted in 7th graders and one which included subjects who were five to 11 years of age. Most of the studies did not report the race/ethnicity of subjects, though one study included a predominantly minority population (>80%), and one included a majority of white subjects (69%). Information regarding the socio-economic status of subjects was also not widely reported; one study only included schools with ≥20% of students eligible for free- or reduced-price meals, and one included schools with 46% to 67% of students eligible for free meals.

The types of modifications made to the school food environment varied between the studies. Types of environmental changes made included:

  • Free breakfast provided at school (Ask, 2006)
  • Increased availability and promotion of fruits and vegetables in the school cafeteria and vending machines (Birnbaum, 2002)
  • Free fruit and vegetable snack (He, 2009; Horne, 2004)
  • Increased choice, marketing, and improvement in the preparation and appearance of fish served in the school cafeteria (Prell, 2005).

Overall, all five studies included in this review showed that combining changes to the school food environment with nutrition education is effective for improving children and adolescent’s dietary intake, and some evidence suggested that the combination led to greater improvement than either making changes to the food environment or providing nutrition education alone.

All four of the studies that compared “nutrition education combined with changes to the school food environment” to “changes to the school food environment alone” found that combining nutrition education with changes to the school food environment improved dietary intake, and provide some evidence that this improvement was greater than when compared to only making changes to the school food environment. Two studies found that dietary intake improved more when children received the combination intervention compared to the food environment alone intervention. In the other two studies, the direct comparison between the combination intervention and the food environment intervention did not differ significantly, though the combination intervention led to improvements compared to control while the food environment alone intervention did not.

  • One study found that combining a peer leadership program with nutrition education and food environment changes improved dietary intake more, compared to nutrition education + food environment changes or food environment changes alone. Nutrition education combined with food environment changes also led to improved dietary intake compared to food environment changes alone (Birnbaum, 2002)
  • One study found that combining nutrition education with changes to the school food environment increased fruit and vegetable consumption at school compared to a control (no intervention). There were no significant differences in school fruit and vegetable consumption between the school food environment group alone and either the control or the school food environment combined with nutrition education (He, 2009)
  • One study found that combining nutrition education with changes to the school food environment led to increased lunchtime, snack time, and home consumption of fruits and vegetables compared to changes to the school food environment only (Horne, 2004)
  • One study found that combining nutrition education with changes to the school food environment led to increased fish consumption compared to a control (no intervention). Changing the school food environment alone did not significantly increase fish consumption compared to either the control group or the group that received the combination of changes to the food environment and nutrition education (Prell, 2005).

The study that compared “nutrition education combined with changes to the school food environment” to “nutrition education alone” found some evidence that combining nutrition education with changes to the school food environment improved dietary intake more than only providing nutrition education. However, the study had mixed results, with some differences that were based on gender:

  • Males who received nutrition education combined with food environment changes increased scores on a unique, author-developed “healthy eating index” compared to no change in scores among males in the nutrition education only group. There were no differences among females between the two groups (Ask, 2006).

Evidence Summary Paragraphs

Ask et al, 2006 (neutral quality) conducted a non-randomized controlled trial in Norway to evaluate the effects of providing nutrition education with or without free breakfast on dietary intake among adolescents. Two classrooms were assigned to one of two conditions for four months: (1) Intervention: Received nutrition education and a free breakfast at the beginning of each school day (nutrition education + changes to the school food environment), and (2) Comparison: Received nutrition education on the importance of healthy eating (nutrition education alone). Dietary intake-related outcomes were assessed using a non-validated 27-item FFQ, and eleven food items from the FFQ were used to calculate an author-created “healthy eating index” score. The final sample included 54 subjects (mean age=15 years). Results showed that males in the intervention group had a significant increase in their healthy eating index score (P<0.001), while there was no change among males in the comparison group. There were no changes in the healthy eating index scores of females in either the intervention or the comparison group.

Birnbaum et al, 2002 (positive quality) conducted an RCT in the US to evaluate the effects of school-based, multi-component nutrition interventions on dietary intake among adolescents. Schools were randomly assigned to one of four conditions for two years: (1) Intervention 1: Received a peer leadership component plus classroom nutrition education plus an environmental intervention (increased availability and promotion of fruits and vegetables in the school cafeteria and vending machines) (nutrition education + changes to the school food environment), (2) Intervention 2: Received classroom nutrition education plus the school environment intervention (nutrition education + changes to the school food environment), (3) Intervention 3: Received the school environment intervention only (changes to the school food environment only), (4) Control: Did not receive any intervention. Dietary intake-related outcomes (average number of daily fruit and vegetable servings) were measured using a validated modified version of the Behavioral Risk Factor Surveillance System (BRFSS) survey. The final sample included 3,503 students (7th grade at baseline, 9th grade at follow-up). The peer leaders + nutrition education + food environment group significantly increased fruit and vegetable intake (+1.0 serving; P<0.05) and fruit intake (+0.5 serving; P=0.01), with a borderline significant increase in vegetable intake (+0.4 servings; P=0.059). The nutrition education + food environment group had a borderline significant increase in fruit and vegetable intake (+0.5 servings; P=0.056) and fruit intake (+0.25 servings; P=0.052). There were no significant changes in fruit and/or vegetable intake in either the food environment alone or control groups.

He et al, 2009 (neutral quality) conducted an RCT in Canada to measure the influence of the Northern Fruit and Vegetable Pilot Program on children’s fruit and vegetable consumption. Schools were randomly assigned to one of three groups for the 21-week intervention: (1) Intervention 1: Received a free fruit and vegetable snack (three times per week) and enhanced classroom nutrition education (nutrition education + changes to the school food environment), (2) Intervention 2: Received a free fruit and vegetable snack (three times per week) (changes to the school food environment only), and (3) Control: Did not receive any intervention. Dietary intake-related outcomes (fruit and vegetable servings as defined by Canada’s Food Guide to Healthy Eating) were measured using a 24-hour fruit and vegetable recall questionnaire. The final sample included 1,277 students (mean age=12 years). Children in the nutrition education + changes to the school food environment group consumed more fruits and vegetables at school compared to control (0.49 serving/d; P<0.05). There were no significant differences in school fruit and vegetable consumption between the school food environment group and the control group. There were no significant differences between any of the groups in fruit and vegetable intake at home or total fruit and vegetable intake.

Horne et al, 2004 (positive quality) conducted a non-randomized controlled trial in the United Kingdom to evaluate a peer-modeling and rewards-based intervention designed to increase children's fruit and vegetable consumption. Schools were assigned to one of two groups for 16 days (followed by a four-month maintenance phase): (1) Intervention: Received fruit at snack time, rewards for consuming the fruit (“Food Dude” school supplies), and peer-modeling nutrition education videos (nutrition education + changes to the school food environment), (2) Comparison: Received fruit at snack time and rewards for consuming the fruit (changes to the school food environment only). Dietary intake-related outcomes were measured after the intervention and during the maintenance phase using visual estimation by trained observers (fruit and vegetable consumption at lunch) weighed intake (fruit and vegetable consumption at snack), and a 24-hour recall completed by parents after the intervention (fruit and vegetable consumption at home). The final sample included 749 children (ages five to 11 years). Lunchtime consumption of fruits and vegetables in the nutrition education + changes to the school food environment group was significantly higher immediately after the intervention and after the maintenance phase than baseline (P<0.001), while snack time consumption was higher immediately after the intervention than baseline (P<0.001) compared to changing to the school food environment only, but not after the maintenance phase. There were also significant increases in fruit and vegetable consumption at home immediately after the intervention (P<0.05).

Prell et al, 2005 (neutral quality) conducted an RCT in Sweden to examine the effects of school-based interventions on fish consumption among adolescents. Schools were randomly assigned to one of three groups for five weeks: (1) Intervention 1: Received changes to the school cafeteria (increased choice, marketing, and improved preparation/appearance of fish) and home economics nutrition education (nutrition education + changes to the school food environment), (2) Intervention 2: Received changes to the school cafeteria (changes to the school food environment only), or (3) Control: Did not receive any intervention. Dietary intake-related outcomes (fish consumption) were measured using structured observations in the school cafeteria once a week when fish was served. The final sample included 228 subjects (mean age=14 years). The nutrition education + changes to the school food environment group significantly increased fish consumption following the intervention, compared to the control group (P<0.01). The school food environment only group did not significantly increase fish consumption, compared to either the control group or the group that received changes to the school food environment only.


Click Table 4-D.1. to see Overview Table on Studies Examining the Effects of Nutrition Education Combined with Changes to the Food Environment.




Research Design and Implementation
For a summary of the Research Design and Implementation results, click here.