Garden Based Nutrition Study

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RESEARCH

Review

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Impact of Garden-Based Youth NutritionIntervention Programs: A ReviewRAMONA ROBINSON-OBRIEN, PhD, RD; MARY STORY, PhD, RD; STEPHANIE HEIM, MPH

ABSTRACTGarden-based nutrition-education programs for youthare gaining in popularity and are viewed by many as apromising strategy for increasing preferences and im-proving dietary intake of fruits and vegetables. This re-view examines the scientific literature on garden-basedyouth nutrition intervention programs and the impact onnutrition-related outcomes. Studies published between1990 and 2007 were identified through a library search ofdatabases and an examination of reference lists of rele-vant publications. Studies were included if they involvedchildren and adolescents in the United States and exam-ined the impact of garden-based nutrition education onfruit and/or vegetable intake, willingness to taste fruitsand vegetables, preferences for fruits and vegetables, orother nutrition-related outcomes. Only articles published

in peer-reviewed journals in English were included in the

review. Eleven studies were reviewed. Five studies tookplace on school grounds and were integrated into the

school curriculum, three studies were conducted as partof an afterschool program, and three studies were con-ducted within the community. Studies included youthranging in age from 5 to 15 years. Findings from thisreview suggest that garden-based nutrition interventionprograms may have the potential to promote increasedfruit and vegetable intake among youth and increasedwillingness to taste fruits and vegetables among youngerchildren; however, empirical evidence in this area is rel-atively scant. Therefore, there is a need for well-designed,evidenced-based, peer-reviewed studies to determine pro-gram effectiveness and impact. Suggestions for futureresearch directions, including intervention planning,study design, evaluation, and sustainability are provided.J Am Diet Assoc. 2009;109:273-280.

Concern for the health and nutritional intake of youthin the United States remains a national priority,and food and nutrition professionals and nutrition

educators continue to seek innovative and effective ap-proaches to improving dietary intake among children andadolescents. Optimal fruit and vegetable intake is asso-ciated with good health and reduced disease risk. Re-search documents that fruit and vegetable consumptionplays a protective role in the prevention of cardiovasculardisease, certain cancers, obesity, and other chronic con-ditions (1,2). Despite the evidence in support of hea lthbenefits associated with fruit and vegetable intake (1),

national data indicate that fewer than half of boys andgirls ages 4 to 18years consume5 servings of fruits andvegetables daily (3). National efforts are currently under-way to promote increases in fruit and vegetable intakeamong youth. There is evidence indicating that school-based nutrition-education programs may produce moder-ate increases in fruit and vegetable consumption amongyouth (4). However, nutrition intervention strategies maybe moreeffective in increasing fruit rather than vegetableintake (5). Garden-based nutrition-education programsmay be an ideal venue to encourage increased intake ofvegetables as well as fruits, as they often include theopportunity for youth to plant, harvest, and prepare a

R. Robinson-OBrien is an assistant professor, NutritionDepartment, College of Saint BenedictSaint JohnsUniversity, St Joseph, MN; at the time of the study shewas a postdoctoral fellow, Adolescent Health ProtectionResearch Training Program, Division of Epidemiologyand Community Health, University of Minnesota, Min-neapolis. M. Story is a professor, Division of Epidemiol-ogy and Community Health, School of Public Health,University of Minnesota, Minneapolis. S. Heim is a clin-ical dietitian, Department of Endocrinology, MayoClinic, Rochester, MN; at the time of the study, she was

an adolescent health fellow, Division of Epidemiologyand Community Health, University of Minnesota, Min-neapolis.

Address correspondence to: Ramona Robinson-OBrien,PhD, RD, Nutrition Department, College of SaintBenedictSaint Johns University,37 South CollegeAve, St Joseph, MN 56374. E-mail: [email protected]

Manuscript accepted: August 15, 2008.Copyright 2009 by the American Dietetic

Association.0002-8223/09/10902-0007$36.00/0doi: 10.1016/j.jada.2008.10.051

2009 by the American Dietetic Association Journal of the AMERICAN DIETETIC ASSOCIATION 273
http://www.eatright.org/obchttp://www.eatright.org/obchttp://www.eatright.org/obcmailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]://www.eatright.org/obc


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vast array of vegetables and some fruits (eg, berries,melons). With multiple exposures to fruits and vegetablesthrough hands-on experiences among their peers, youthmay increase their fruit and vegetable intake (6).

Youth garden education programs have been imple-mented within school and community settings throughoutthe United States. The National Gardening Association in-

dicates a proliferation of garden education programs acrossthe country (7). There have been numerous anecdotal re-ports of a variety of healthful youth development outcomesresulting from youth participation in garden programs(8);however, evidenced-based, peer-reviewed research evaluat-ing the impact of participation in garden programs on nu-tritional outcomes is limited. Garden program leaders havenoted improvements in a wide range of characteristicsamong youth, including environmental attitudes, commu-nity spirit, social skills, self-confidence, leadership skills,volunteerism, motorskills, scholastic achievement, and nu-tritional attitudes (7). In recent years, numerous local andnational initiatives have included components to teach foodand nutrition through connections with gardens. Examplesof theseinitiatives include: The Edible Schoolyard in Cali-

fornia (9), The Youth Farm and Market Program (10), Com-munity Design Center in Minnesota (11), The NationalFarm-to-School Program (12), and The National GardeningAssociation, Kids Gardening Initiative (13). Garden pro-grams have the potential to result in a range of benefitsassociated with positive youth development and offer ahands-on opportunity to develop a greater understanding offood systems through the cultivation of connections withfood, the environment, and community.

While garden-based nutrition-education programs maybe a promising strategy for improving dietary intakeamong youth, there is a need for a preliminary evaluationof existing peer-reviewed literature regarding this inter-vention approach. This review includes articles published

in peer-reviewed journals and provides an evaluation ofgarden-based nutrition intervention programs and theirimpact on youth fruit and vegetable intake, willingness totaste fruits and vegetables, preferences for fruits andvegetables, and other nutrition-related outcomes. As reg-istered dietitians and food and nutrition professionalscontinue to seek creative, innovative, and effective nutri-tion-education strategies aimed at improving youth di-etary intake, this review offers insight into the potentialeffectiveness of utilizing garden-based nutrition interven-tion programs and provides suggestions for future re-search directions.

METHODS

Articles published from 1990 through June 2007 wereidentified by searching PubMed, Argricola, ERIC, andPsychINFO databases. The following keywords weresearched singularly and in various combinations: youth,children, school gardens, community gardens, nutritioneducation, and dietary behaviors. Articles were includedin this review if they examined the impact of garden-based nutrition education on youth fruit and vegetableintake, willingness to taste fruits and vegetables, prefer-ences for fruits and vegetables, or other nutrition-relatedoutcomes. Articles were limited to those that targetedchildren and adolescents in the United States. Only arti-cles published in peer-reviewed journals in English were

included in this review. Articles were excluded if thetarget population focus was on adults, elders, or the com-munity as a whole. Eleven studies were identified thatmet the review criteria (14-24).

The review is organized by first providing an overviewof the study characteristics. Then descriptions of inter-vention methodologies and measurement tools, and sum-

maries of study outcomes are provided for two generalcategories of studies: in-school garden-based nutrition-education research and afterschool or community garden-based nutrition-education research. Implications for fu-ture research are discussed.

Overview of Study Characteristics

The 11 studies represented a variety of geographic re-gions, including year-round warm-weather climates andthose with colder-winter climates. The studies utilized avariety of intervention designs and measurement toolsranging in intensity and rigor. The studies differed inintervention design methodology and in the types of eval-uation tools utilized to evaluate outcomes. Five studieswere located on school grounds and were integratedwithin the school curriculum (14-18), three were con-ducted as part of an afterschool program (19-21), andthree were conducted within the community (22-24).Studies included youth ranging in age from 5 to 15 years,with the majority of participants in third through sixthgrade. Five of the 11 studies included intervention andcontrol or comparison groups (14-16,19,21), of whichthree studies included a comparison of garden-based nu-trition education with nutrition education alone(14,15,21), five studies used prepost tests within thesame population (17,18,20,22,24), and one study reportedthemes from focus groups (23). Investigations routinelyrelied on convenience samples and varied in intensity as

well as duration; with one study reporting 6-month fol-low-up data (15). Evaluation tools included 24-hour recallworkbooks, surveys, one-on-one interviews, and focusgroups. The majority of investigators reported attemptsto use tools with known reliabilities and/or validatedmeasures.

Outcomes evaluated in this review include fruit andvegetable intake(14,17,20,22), willingness to taste fruitsand vegetables (15,16,18), and fruit and vegetable pref-erences (15-17,19,21,24). This review also includes out-comes of fruit and vegetable knowledge (16,18,19,21,24),self-efficacy to consume fruits and vegetables (19,21), andother nutrition-related outcomes. Findings from a quali-tative study with youth who participated in a summer

gardening program are also included in this review (23).

Overview of Studies

Figure 1represents the characteristics of each study re-viewed, including study location, population, design andduration, measurement tools utilized, and study out-comes. The following overview of the literature providesmore detail about study design, measurement tools andmethodologies, and the impact of youth garden-basednutrition education on fruit and vegetable intake, will-ingness to taste fruits and vegetables, fruit and vegetablepreferences, and other nutrition-related outcomes.

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In-School Garden-Based Nutrition Education Research

McAleese and Rankin (14) evaluated the impact of a12-week in-school intervention on fruit and vegetableintake among sixth-grade students from three south-east Idaho elementary schools: two intervention schools(n70) and one control school (n25). The interventionschools were divided into nutrition education alone (n25)

and nutrition education combined with food preparationand gardening activities (n45), including weeding, water-ing, and harvesting strawberries, cantaloupe, and a varietyof fall crops. Three 24-hour food recalls in the form of work-books were completed by students at baseline and again 12weeks later. Classroom teachers administered food-recallworkbooks, which included age-appropriate instructionsand portion-size illustrations. Students participating in thenutrition education combined with garden experiences in-creased significantly (P0.001) their daily intake of fruitsand vegetables from 1.9 to 4.5 servings, when compared to2.1 to 2.2 servings among students in the nutrition-educationonly group and 2.4 to 2.0 servings among stu-dents in the control group. In addition, students participat-

ing in the nutrition education combined with gardenexperiences significantly increased vitamin A, vitamin Cand fiber intake. A strength of this study design was that itevaluated whether garden participation would enhance in-take more than nutrition educationalone.

Morris and Zidenberg-Cherr (15)evaluated the impactof a 17-week, in-school intervention (delivered everyother week) on vegetable preferences, willingness to tastevegetables, and nutrition knowledge among students(n213; fourth grade) from three California elementaryschools: two intervention schools and one control school.The nutrition-education program was based on the SocialCognitive Theory. One intervention school received nu-trition-educationonly using a nine-lesson classroom-

based nutrition curriculum developed by investigators.The second intervention school received nutrition educa-tion combined with garden activities, including experi-ences with planting, maintaining, and harvesting. Studyevaluation was conducted in the fall (pretest) and spring(posttest), and included 6-month postintervention fol-low-up data. Investigators reported utilizing previouslyvalidated methodology to assess vegetable preferences(25-27). Compared to the control group, posttest preferencescores for carrots and broccoli were greater for the gardenactivities and nutrition education group and nutrition-educationonly group. Compared to the control and nutri-tion-educationonly groups, posttest preference scores forsnow peas and zucchini were greater for garden activities

and nutrition-education group. At 6 months, the gardenactivities and nutrition-education group retained greaterpreferences for broccoli, snow peas, and zucchini. No differ-ences between groups were found in willingness to tastevegetables. Nutrition knowledge was also assessed via anutrition-knowledge questionnaire, previously tested for re-liability and content validity. Compared to the controlgroup, students in the garden activities and nutrition-edu-cation group and nutrition-educationonly group had con-siderably higher posttest nutrition-knowledge scores, ad-justed for pretest scores, and improvements weremaintained at 6-month follow-up. A strength of this studywas that it evaluated whether garden participation would

enhance outcomes more than nutrition education alone andit included 6-month postintervention follow-up data.

Morris and colleagues (16)evaluated the impact of an8-month in-school, feasibility/pilot study on vegetablepreferences, willingness to taste vegetables, and nutri-tion knowledge among students (n97; first grade) fromtwo California elementary schools: one control school and

one intervention school. The nutrition-education programwas guided by Social Cognitive Theory. The interventionschool included nutrition-education curriculum and gardenactivities, including planting, maintaining, and harvestingfall and spring gardens growing spinach, carrots, peas, andbroccoli. The control school received no formal nutritioneducation or garden opportunities. Vegetable preferencesand willingness to taste vegetables were assessed via one-on-one interviews with trained interviewers in fall (pretest)and spring (posttest). Investigators reported using previ-ously validated methodology for the vegetable tasting as-sessment (25). Posttest preferences for vegetables were notsubstantially improved in the intervention or control group,averaging1.25, on a scale of 0 to 2. At posttest, interven-tion students were more willing than control students totaste spinach, carrots, peas, broccoli, zucchini, and red bellpepper (P0.005). Authors speculated that the limitednumber of taste-testing opportunities may have influencedtheir preference results, although it is unclear how manytaste-testing opportunities children received. Nutritionknowledge, within the intervention group indicated sub-stantial improvements in the ability to identify food groups,but no change in ability to correctly identify vegetables. Astrength of this study was that it provided informationabout young childrens willingness to taste vegetablesgrown in the garden.

Lineberger and Zajicek (17)evaluated the impact of a10-unit, 1 year, in-school intervention on fruit and vege-table intake and fruit and vegetable preferences among

students (n111; third to fifth grade) from five Texaselementary schools. All students were exposed to theintervention, including nutrition education combinedwith garden and food preparation activities. Teachersintroduced information from each of the 10 units in thecurriculum, but were allowed to adapt materials to ac-commodate classroom schedules. Fruit and vegetable in-take and fruit and vegetable preferences were assessed inthe spring (pretest) and again the following spring (post-test). Fruit and vegetable intake was assessed via 24-hour food-recall workbooks. No improvements in fruitand vegetable intake were found. Fruit and vegetablepreferences were assessed via a previously developedfruit and vegetable preference questionnaire (28). Stu-

dents showed improvements in vegetable preferences andpreferences for fruits and vegetables over another snackitem; however, no changes in fruit preferences were de-tected. A strength of this study was that it includedstudents from five different schools.

Cason (18)evaluated the impact of an in-school inter-vention on willingness to taste fruits and vegetables andfruit and vegetable identification among kindergartenstudents from three classes at one elementary school inSouth Carolina. This study was not presented as a re-search article, but rather as a description of an innovativeapproach to nutrition education. AKinderGarden com-mittee, consisting of teachers, school administrators, par-



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ents, business and industry volunteers, and extensioneducators were involved with planning and implementa-tion of the intervention. All students were exposed tonutrition education and garden activities. Nutrition edu-cation was integrated into existing language arts andscience curriculum, delivered for 30 minutes each week,and included food preparation and tasting activities. Gar-

den exposure included 30 minutes per week (working ingroups of 10) in the school garden. Pre- and postdataindicated a 69% increase in willingness to taste fruits andvegetables. In addition, the percentage of students able tocorrectly identify fruits increased from 52% to 94% andvegetables increased from 43% to 86%. A strength of thisstudy was that it included the use of a committee todevelop and implement the intervention.

Afterschool and Community Garden-Based Nutrition-EducationResearch

Guided by Social Cognitive Theory, OBrien and Shoe-maker (19)evaluated the impact of a 10-week (weekly, 80minutes), afterschool intervention on fruit and vegetable

preferences, nutrition knowledge, and self-efficacy to con-sume fruits and vegetables among children (n38; fourthgrade) from two similar Kansas elementary schools: onecontrol group (n21) and one intervention group (n17)of participants in an afterschool gardening club. Eachweek, children in the intervention group received nutri-tion lessons, gardened for 30 minutes and consumed ahealthful snack. Fruit and vegetable preferences, nutri-tion knowledge, and self-efficacy to eat fruits and vegeta-bles were assessed. Fruit and vegetable preference (28)and self-efficacy (27)questions were based on previouslyvalidated measures. There were no significant improve-ments in fruit and vegetable preferences or nutritionknowledge; however, investigators noted that thesescores were high at the beginning and end of the inter-

vention. Self-efficacy to consume fruits and vegetablesincreased among the intervention group participants, butinvestigators did not report whether or not this increasewas statistically significant.

Hermann and colleagues (20) evaluated the impact ofan afterschool intervention facilitated through OklahomaCooperative Extensive Services (1 day per week, for 90minutes) on vegetable intake among youth (n43; thirdto eighth grade). The intervention utilized existing cur-ricula and the garden embraced the three sisters gar-den (corn, beans, and squash) of the Native Americanculture. Native American youth comprised nearly 75% ofthe sample. Youth planted, maintained, and harvested adozen vegetables in the garden. Youth received nutrition

education and prepared healthful meals and snacks withthe harvested produce. Vegetable intake was assessedwith a single question at baseline and follow-up. Thepercent of youth who reported, I eat vegetables everyday, significantly increased (P0.02) from 22% at base-line to 44% at follow-up. Strengths of this study includedthe use of diverse hands-on activities as well as the in-volvement of community members and parents who as-sisted with garden activities and local businesses whodonated supplies. Furthermore, schoolteachers utilizedthe garden with their classes, which resulted in theschool seeking and receiving financial resources to pur-chase a greenhouse.

With Social Cognitive Theory as a framework, Postonand colleagues (21)evaluated the impact of an interven-tion on fruit and vegetable preferences, knowledge, andself-efficacy to consume fruits and vegetables among chil-dren (n29; third to fifth grade) recruited from a Boysand Girls Club in Kansas. Eighteen children participatedin an 8-week (20 to 60 minutes/lesson) Junior Master

Gardeners program, while 11 participated in a five-les-son (30 to 60 minutes/lesson) nutrition-educationonlyprogram. The program was implemented in the fall andsummer with one intervention each time and one com-parison group in the summer. Children in the interven-tion group consumed a healthful snack, completed thelesson, and gardened for 10 to 15 minutes. Fruit andvegetable preference (28)and self-efficacy (27)questionswere based on previously validated measures. There wereno increases in fruit and vegetable preferences, nutritionknowledge, or self-efficacy to consume fruits and vegeta-bles in either group. Investigators suggested that thesmall sample size, limited program length, and limitedgarden time may have influenced outcomes.

Lautenschlager and Smith (22)evaluated the impact ofa 10-week community-based intervention (3 days a weekfor 10 weeks) on fruit and vegetable intake among youth(n96 baseline, n66 follow-up; ages 8 to 15 years) inMinneapolis/St Paul, MN. Participants were exposed tonutrition, cooking, and gardening lessons in the summer.Fruit and vegetable intake was determined by a combi-nation of measurement tools, survey questions, and recalldata. Responses to survey questions How many pieces offruit did you eat yesterday? and How many vegetablesdid you eat yesterday? were averaged with fruit andvegetable intake data derived from 24-hour recalls. Boysfruit and vegetable intake significantly increased frombaseline to follow-up, whereas girls intake did not

change. Boys intake of fruit increased from 2.0 to 3.0servings (P0.029) and vegetables increased from 2.0 to3.4 (P0.007). Lautenschlager and Smith (23) also con-ducted six focus groups with two populations of inner-cityyouth: those involved in the garden program (threegroups, n26) and those with no exposure to the program(three groups, n14). Investigators determined thatwhen compared to the nongarden participants, youth gar-den participants were more willing to eat nutritious food,try ethnic and unfamiliar food, expressed a greater ap-preciation for individuals and cultures, and were morelikely to cook and garden.

Koch and colleagues (24)evaluated the impact of a com-munity-based intervention on fruit and vegetable prefer-

ences, consumption of a healthful snack, and knowledge ofthe benefits of fruits and vegetables among youth (n56;second to fifth grade) in four Texas counties. Interventiondelivery was determined by each county agent and rangedfrom a 1-week summer camp format to once per week for 12weeks. All participants were exposed to the intervention,which included nutrition education and garden activities.Fruit and vegetable preferences were assessed via a previ-ously developed questionnaire(28). Following the interven-tion there were no improvements in fruit and vegetablepreferences; however, improvements in healthful snack con-sumption and knowledge about the benefits of eating fruitsand vegetables were reported.

February 2009 Journal of the AMERICAN DIETETIC ASSOCIATION 277


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Summary of Outcomes

Outcomes investigated in this review included four stud-ies evaluating changes in fruit and/or vegetable intake(14,17,20,22), six studies evaluating changes in fruitand/or vegetable preferences (15-17,19,21,24), and threestudies evaluating changes in willingness to taste fruitand/or vegetables (15,16,18). Three studies reported that

exposure to garden-based nutrition education was asso-ciated with increased fruit and vegetable intake (14,22) orvegetable intake (20) among youth, one study reportedthat significant increases in fruit and vegetable intakewere only seen in boys (22). One study reported no im-provements in fruit and vegetable intake (17). Two stud-ies reported that exposure to garden-based nutrition ed-ucation was associated with increased preference forvegetables (15,17), whereas four studies reported no im-provements in preferences for fruits (17,19,21,24)or veg-etables (16,19,21,24). One study found that children re-ported an increase in fruit and vegetable snack preferenceupon exposure to garden-based nutrition education (17).Two studies with younger children in kindergarten and firstgrade reported that exposure to garden-based nutrition pro-grams resulted in increased willingness to taste fruits andvegetables (18)or vegetables (spinach, carrots, peas, broc-coli) (16); while one study with fourth graders reported noimprovements in willingness to taste vegetables (15). Thisincreased willingness to taste fruits and vegetables amongthe youngest children in kindergarten(18)and first grade(16) is encouraging, as it could potentially lead to developingincreased fruit and vegetable preferences and fruit and veg-etable intake as they grow older (29).

While the primary outcomes of interest in this reviewwere fruit and vegetable intake, willingness to tastefruits and vegetables, and fruit and vegetable prefer-ences, other nutrition-related outcomes are worth noting.Many of the studies also assessed changes in nutrition

knowledge. Four studies reported that exposure to gar-den-based nutrition education was associated with in-creased nutrition knowledge (15,16,18,24), whereas twostudies did not report improvements in nutrition knowl-edge following intervention programming (19,21). Mea-surement of knowledge ranged from the ability to identifyfood groups among younger children to the ability torecognize the benefits of fruits and vegetables and gen-eral nutrition knowledge among older children. While onestudy reported no increase (21)in self-efficacy to consumefruits and vegetables, another study reported improve-ments, but not whether these improvements were statis-tically significant (19). Other outcomes associated withexposure to garden-based nutrition education included

increased intake of vitamin A, vitamin C, and fiber (14);increased likelihood to cook (23); and increased appreci-ation for other individuals and cultures (23).

Collectively, results from the studies in the currentreview provide some important insight into the feasibilityand effectiveness of garden-based nutrition education;however, most involve limitations in evaluation method-ology and study design. Investigators utilized differentevaluation tools to measure fruit and vegetable intake,which may have influenced outcomes. One study utilizeda single item question to assess vegetable intake, anotherused a combination of survey questions and 24-hour re-call data, and two other studies reported the use of a

validated 24-hour recall workbook to measure intake;however, the 24-hour recall validation process has notbeen published in a peer-reviewed journal. Studies were

limited by small sample sizes, lack of long-term follow-updata, and lack of process survey data. In addition, some ofthe study descriptions would have been more completewith additional details about intervention design andinformation regarding the successes and challenges ofstudy implementation. It is important that future studiesinclude systematic process evaluation reports to informfuture research interventions.

With regard to study design, investigators routinelyrelied on convenience samples involving youth who mayor may not have had a prior interest in nutrition orgardening, thus biasing the results and limiting theirgeneralizability. In addition, while studies provided pre-

Intervention Planning Include a formal needs assessment prior to implementing

intervention Involve a variety of stakeholders (including youth) in the

intervention planning process Use theory-based quantitative and qualitative investigation

methods to guide intervention planning Consider principles in Community-Based Participatory

ResearchStudy Design and Evaluation Methodology

Convene a workgroup to determine research design andevaluation recommendations for school and communitygarden-based nutrition-education interventions

Use previously validated tools, or pilot test and validateassessment tools prior to use

Include sample sizes large enough to evaluate independentimpacts of sex, age, and cultural group

Evaluate independent effects of garden-based nutritioneducation and traditional nutrition education

Evaluate which aspects of intervention design are mostcritical: program time, gardening time, gardening method,

and season Use control groups and if resources allow, consider group

randomized trials with a minimum of six groups percondition

Conduct longitudinal research to track whether changes inintake and attitudes alter over time

Outcome Measures Evaluate changes in dietary intake among youth and their

families as well as other physical and health-relatedoutcomes

Examine which aspects of the garden-based nutritioneducation are most critical: participation in garden planning,planting, maintenance, and harvest; food preparation;tasting; nutrition-education lessons

Program Sustainability Evaluate the facilitators and barriers to long-term

sustainability of programming Include process survey data in evaluation, in a effort to

inform future interventions Link school subjects and learning objectives to garden-

based education and assess/monitor the outcomes

Figure 2. Considerations when implementing and evaluating garden-based youth nutrition-education programs.



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and postintervention data, some did not include a controlcondition and most of the studies that included controland comparison groups assigned only one group per con-dition, which may have compromised the statistical out-comes due to possible clustering. Ignoring the clusteringof observations within intact social groups (ie, studentswithin one school) leads to underestimated standard er-

rors, and thus the test of treatment differences is toosensitive giving P values that are too small. To ensurestatistical rigor, future research may include quasi-ex-perimental interventions with a minimum of six groupsper condition in order to estimate appropriate standarderrors (30). With the growing national interest in garden-based nutrition education, the need for well-designedstudies is critical. It would be beneficial to convene aworkgroup to address concerns inherent in these types ofcommunity-based projects and make recommendationsfor effective study designs and evaluation methodologies.Research considerations for implementing and evaluat-ing garden-based youth nutrition-education programs areprovided inFigure 2.

CONCLUSIONS AND IMPLICATIONS FOR FUTURE PRACTICE

AND RESEARCH

There is a growing movement among educators to includegardens as a teaching tool within schools and communi-ties, as evidenced by the number of youth participating ingarden education programs(7,8). Schools throughout thecountry may consider integrating garden-based educa-tion into the curriculum as part of the school wellnesspolicies required by the Child Nutrition ReauthorizationAct of 2004, as research suggests garden-based educationmay lead to improved academic achievement (31-35). In

addition, cooperative partnerships linking school, after-school, and community garden programs could allow forcontinuity of programming and enhanced learning oppor-tunities for youth, families, and community membersthroughout the year.

Based on the review of relevant but relatively limitedliterature, the evidence for the effectiveness of garden-based nutrition education is promising. Garden-based nu-trition-education programs may have the potential to leadto improvements in fruit and vegetable intake, willingnessto taste fruits and vegetables, and increased preferencesamong youth whose current preferences for fruits and veg-etables are low. However, it is difficult to make conclusionsbased on the limited number of well-designed, methodolog-

ically peer-reviewed research studies available. Future re-search is needed to investigate whether garden-based nu-trition-education programs positively impact dietaryoutcomes among youth. With high obesity rates amongyouth in the United States (36), it is imperative to investi-gate creative and effective healthful eating initiatives.

This article was supported by the Adolescent Health Pro-tection Program grant number T01-DP000112 from theCenters for Disease Control and Prevention (CDC). Itscontents are solely the responsibility of the authors anddo not necessarily represent the official views of the CDC.

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Documents

Garden Based Nutrition Study