Nutrition to Grow On

According to the Dietary Guidelines for Americans 2005, good nutrition is essential for the healthy growth and development of children and adolescents.  People who consume more fruits and vegetables as part of a healthful diet are likely to lower their risk of cancers in certain sites (oral cavity and pharynx, larynx, lung, esophagus, stomach, and colon-rectum) and chronic diseases (type 2 diabetes and cerebral vascular disease), compared with people who consume small amounts of fruits and vegetables.  The 2010 Dietary Guidelines Advisory Committee recommends shifting food intake patterns to a more plant-based diet that emphasizes vegetables, cooked dry beans and peas, fruits, whole grains, nuts, and seeds, while consuming only moderate amounts of lean meats, poultry, and eggs. 

Nutrition to Grow On is a nutrition education curriculum for 4th-grade students that uses gardening to teach children healthy eating habits as they learn how to plant and harvest their own vegetables. The curriculum consists of nine nutrition lessons: plant parts, nutrients, Food Guide Pyramid, serving sizes, food labels, physical activity, goal-setting, consumerism, and snack preparation. These lessons are complemented with gardening activity according to the following topics: indoor seed planting, worm bottles, outdoor seed planting, weed identification, bug boxes, garden fertilization, seed dispersal, butterflies, and crop harvest.

Each lesson in the curriculum includes objectives, material lists, a nutrition lesson plan, a gardening lesson plan, background information for teachers, additional activities, all necessary handouts, and a family newsletter that can be sent home to provide information and activities for the family to enjoy together.  Students plant seeds in mini-greenhouses and study the growing process as a unique enhancement to the nutrition education lessons.  The gardening activities meet certain California state math, science, and English-language arts and academic content standards for 4th through 6th grades.  The curriculum manual includes recommendations on how to teach many of the gardening activities in a classroom setting for teachers who have limited or no garden space available.  An initial letter is sent home to parents to introduce the program and solicit parental support, along with a family newsletter that goes home with students following each lesson. The newsletter reinforces concepts taught in class, educates the students' families about what is being learned in class, and promotes family discussion about healthful eating choices since there is evidence that parental involvement is necessary for the success of any educational program. 

The individual lessons in the Nutrition to Grow On curriculum are designed to be delivered biweekly over a 17-week period.  Each nutrition lesson is intended to last approximately 1 hour, and the hands-on gardening activity may be taught in about 30 minutes. Most activities can be modified to increase or decrease lesson duration as needed. The nutrition and gardening activities are meant to be complementary and are usually taught within a day of each other, although the associated gardening activity may follow the nutrition lesson by as much as a week.  Some advance preparation time (variable) is required the day before to assemble and prepare each in-class nutrition lesson and gardening activity.

The intervention targets 4th-grade elementary school students.

The intervention is suitable for implementation in elementary schools.

-- Nutrition to Grow On manual
    (Complete manual available at http://www.cde.ca.gov/ls/nu/he/documents/ntrtogrow.pdf)

A quasi-experimental study evaluated the effects of a garden-enhanced nutrition education curriculum on 4th-grade students. Three 4th-grade classrooms in each of three schools matched on students' demographic profiles were assigned to one of three conditions for 17 weeks: the target nine-lesson, garden-enhanced nutrition education curriculum; a nine-lesson nutrition education curriculum (with no gardening activities); and a no nutrition education/no garden control. A total of 213 fourth-graders (aged 9-10 years) across the three school sites participated in the study with parental consent. There were 81 students in the school receiving the in-class nutrition lessons and hands-on gardening activities, 71 students in the school receiving only the in-class nutrition lessons, and 61 students in the school designated as the control site (receiving no formal nutrition education or gardening activities). The student sample was 66.5% White, 17.2% Hispanic, 8.4% African American, and 3.0% Asian American, with 25% of the students qualifying for free and reduced-price lunches.

All participating students completed a nutrition knowledge questionnaire that was read aloud to each class and a vegetable preference survey at baseline (October-November), at post-curriculum (March-April), and at a 6-month post-curriculum follow-up at the beginning of 5th grade (the following September and October) when students were aged 10-11 years.  The nutrition knowledge questionnaire was a 30-item multiple-choice instrument based on the objectives of each of the nine nutrition lessons with a maximum possible score of 30. The vegetable preference survey asked students to taste and rate their preference for six different vegetables (carrots, broccoli, spinach, snow peas, zucchini, and jicama). Students were presented with a tray of vegetables in whole and cut-up form and asked if they wanted to taste the vegetable. Those students choosing to taste were asked to indicate their preference for each vegetable according to a 5-point scale that varied from "5 = really liked it a lot" to "1= really did not like it."  There were no differences in students' willingness to taste the raw vegetables across the three school condition sites.  The follow-up rate at the post-curriculum assessment was 96.2% (205 students) and 90.1% (192 students) at the 6-month post-curriculum follow-up.

• Post-curriculum preference ratings by 4th-graders in the garden-enhanced and the nutrition education only schools were higher than preference ratings by 4th-graders in the control school for carrots (4.7 and 4.7 versus 4.4, adjusted for baseline ratings, p<.005) and broccoli (3.8 and 3.8 versus 3.2, adjusted for baseline ratings, p<.01). Post-curriculum preference ratings by 4th-graders in the garden-enhanced nutrition education school were higher than preference ratings by 4th-graders in the nutrition education only and control schools for snow peas (3.8 versus 3.1 and 2.9, adjusted for baseline ratings, p<.005) and zucchini (4.0 versus 3.2 and 3.1, adjusted for baseline ratings, p<.0005).

• At the 6-month follow-up, preference ratings by 4th-graders in the garden-enhanced nutrition education school were higher than preference ratings by 4th-graders in the nutrition education only and control schools for broccoli (4.0 versus 3.7 and 3.5, adjusted for baseline ratings, p<.05), snow peas (3.7 versus 3.0 and 3.0, adjusted for baseline ratings, p<.05), and zucchini (4.0 versus 3.4 and 3.2, adjusted for baseline ratings, p<.05).
   
• Post-curriculum nutrition knowledge scores for 4th-graders in the garden-enhanced and nutrition education only schools were higher than knowledge scores for 4th-graders in the control school (20.8 and 20.5 versus 17.1, adjusted for baseline scores, p<.0005). The increase in nutrition knowledge by 4th-graders in the garden-enhanced and nutrition only schools over 4th-graders in the control school was maintained at 6-month follow-up (20.8 and 21.2 versus 18.0, adjusted for baseline scores, p<.0005).