Availability of Healthy Snack Foods and Beverages in Stores Near High-Income Urban,Low-Income Urban,and Rural Elementary and Middle Schools in Oregon

Abstract

Background:

Food stores near schools are an important source of snacks for children. However, few studies have assessed availability of healthy snacks in these settings. The aim of this study was to assess availability of healthy snack foods and beverages in stores near schools and examine how availability of healthy items varied by poverty level of the school and rural-urban location.

Methods:

Food stores were selected based on their proximity to elementary/middle schools in three categories: high-income urban, low-income urban, and rural. Audits were conducted within the stores to assess the presence or absence of 48 items in single-serving sizes, including healthy beverages, healthy snacks, fresh fruits, and fresh vegetables.

Results:

Overall, availability of healthy snack foods and beverages was low in all stores. However, there was significant cross-site variability in availability of several snack and fruit items, with stores near high-income urban schools having higher availability, compared to stores near low-income urban and/or rural schools. Stores near rural schools generally had the lowest availability, although several fruits were found more often in rural stores than in urban stores. There were no significant differences in availability of healthy beverages and fresh vegetables across sites.

Conclusions:

Availability of healthy snack foods and beverages was limited in stores near schools, but these limitations were more severe in stores proximal to rural and low-income schools. Given that children frequent these stores to purchase snacks, efforts to increase the availability of healthy products, especially in stores near rural and low-income schools, should be a priority.

Introduction

Snacking has become increasingly prevalent among children in the United States. Since the 1970s, both the percent of children consuming snacks and the frequency of daily snacking occasions have increased.^1–3 Moreover, many of the snacks consumed by children are energy-dense, low-nutrient foods, such as desserts, salty snacks, candy, fruit drinks, and soda.^3,4 These trends in snacking may be contributing to the epidemic of childhood obesity.^1,3

Food stores near schools are an important source of snacks for school-aged children, including those in the elementary grades.^5,6 Studies have shown that small stores, known as corner stores or convenience stores, are concentrated around schools^7,8 and that children visit these stores frequently—often more than once per day—to purchase snack foods and beverages.⁵ For these reasons, stores near schools are increasingly viewed as potential intervention targets for promoting healthier snack choices among children.^5,9 However, few studies to date have assessed availability of healthy snacks in these settings.^10–13 Furthermore, previous studies have been limited to urban settings and only one study examined availability of healthy snacks in stores near low- versus high-income schools.¹³ Thus, little is known about whether healthy snack availability in stores varies by poverty level of the school or rural-urban location.

The aim of the present study was to compare availability of healthy snack foods and beverages in stores located within walking distance of high-income urban, low-income urban, and rural elementary and middle schools. This research was conducted in preparation for a larger intervention study aimed at improving children's snacking habits.

Methods

Sampling Strategy

Food stores were selected based on their proximity within 0.5 mile of elementary and middle schools (grades K–8) in the three study categories: high-income urban, low-income urban, and rural. Schools in the Portland (Oregon) School District comprised the urban sample. High- and low-income schools were characterized by <50% and ≥50% of students eligible for federally subsidized free or reduced-price lunch, respectively. The rural schools were those that had agreed to participate in our larger intervention study. They were located in eight remote communities with populations of 295 to 1960 residents in Union and Wallowa counties, in rural northeast Oregon. On average, 50.2% of students were eligible for free or reduced-price lunch in the rural schools combined. The rural sample was not divided by income level because the intent was to determine whether rural location alone influenced availability of healthy snack products.

To identify stores near the urban schools, a list of business licenses classified by the North American Industry Classification System was obtained from the City of Portland Bureau of Technology Services.¹⁴ Stores near the rural schools were identified using the telephone book and a database from the Oregon Employment Department.¹⁵ From these sources, stores that fell into one of the following categories were extracted: supermarket/grocery store or convenience store/food mart within a gasoline station. A supermarket was defined as a store that sold a wide range of foods and other products, such as clothing or household items. Grocery stores sold canned and dried food, as well as perishable items, such as meat and produce. Convenience stores and food marts were stores with a limited variety of foods. Using a Geographic Information System (ArcGIS 10.1; ESRI, Redlands, CA), stores that fell within a 0.5-mile radial buffer from the geometric center of each school were identified; urban stores that fell into an overlapping buffer of both high- and low-income schools were excluded. Finally, a drive-by ground-truthing procedure was used to confirm the existence of each store, identify stores that had permanently closed, and identify any additional stores in the study areas.

Assessment of Healthy Snack Availability

The goal for assessment was to identify food products that were recommended or were healthier alternatives to the energy-dense snacks and beverages commonly consumed by children. To accomplish this, a checklist was developed for use by a trained surveyor.¹⁶ The checklist included 48 items in four categories: 6 beverages, 18 processed snacks, 17 fresh fruits, and 7 fresh vegetables. A “healthy” snack food or beverage was defined as a single-serving product that met the Institute of Medicine Tier 1 nutrition standards for competitive foods and beverages sold in schools for total calories, total calories from fat and saturated fat, trans fat, total sugars, and sodium.¹⁷ A single serving for beverages was 8 ounces for milk, 4 ounces for juice, and any “grab and go” bottle of plain water. For processed snacks, a single-serving package contained one serving as listed on the nutrition facts label, unless all contents of the package were ≤200 calories. For fruits and vegetables, a single serving was a ready-to-eat product sold as a single item (e.g., an apple) or in a pint-size or smaller container (e.g., cut-up melon or baby carrots).

Data Collection

Stores were surveyed between August and October 2012 by a graduate student who had completed 5 hours of training (classroom and field work) and had achieved 90% agreement, as compared to the trainer (a coinvestigator who was also a registered dietician), on each section of the checklist in two test stores outside of the study area. Procedures for completing the checklist have been described elsewhere.¹⁶

Before data collection, each store owner or manager was contacted by a mailed letter for permission to survey their store. The letter described the study and explained that the surveyor would self-identify upon entering the store, that store customers would not be interviewed, and that the survey would be conducted in a manner that would not interfere with the store's regular service to customers. These procedures were approved by the institutional review board at Oregon Health & Science University (Portland, OR).

Statistical Analysis

Frequency distributions were computed for individual food and beverage items, and chi-squared tests of pair-wise differences were conducted to evaluate the relationship between percentage of each item available and location effect (i.e., high-income urban, low-income urban, or rural). As a secondary analysis, sum scores were calculated for each store consisting of the number of healthy items present within each food category and for all foods and beverages combined, scores were averaged to produce a set of mean sum scores for each location, and t-tests of the mean sum scores across locations were conducted. A p value of ≤0.05 was considered statistically significant. Analyses were completed using Stata software (version 11; StataCorp LP, College Station, TX).

Results

Eighty-eight stores were identified in the three study locations combined. Three store managers declined to participate, resulting in a final sample of 85 stores. Table 1 shows the number and percentage of stores by type (i.e., supermarket/grocery store or convenience store/food mart) in each location. Of note, although a greater percentage of the stores in the rural site were classified as a supermarket or grocery store than in the urban sites, these were small independently owned and operated stores and not chain supermarkets.

Table 1.

Number and Percentage of Stores Surveyed by Type and Study Location, Oregon, 2012

	Stores near high-income urban schools n (%)	Stores near low-income urban schools n (%)	Stores near rural schools n (%)
Supermarket/grocery store	12 (29.3)	6 (20.0)	5 (35.7)
Convenience store/food mart	29 (70.7)	24 (80.0)	9 (64.3)
Total	41	30	14

Table 2 presents findings regarding availability of individual food and beverage items. Stores near high-income urban schools had the broadest range of healthy items within each food category, whereas stores near rural schools had the most limited range. For example, all seven vegetables assessed were found in at least some stores near high-income urban schools, but only one (“other ready-to-eat and single-portion fresh vegetables,” which, in this case, were snap peas) was found in stores near rural schools. Similarly, for most individual food and beverage items, stores near high-income urban schools were more likely to have the item available than stores in the other sites. Products found significantly more often in stores near high-income urban schools than in stores near low-income urban and/or rural schools included healthier versions of chips, yogurt, applesauce, canned/bottled fruit, and dried fruit, as well as fresh cherries, cut-up melon, cut-up pineapple, mixed fresh fruit, and “other ready-to-eat and single-portion fresh fruit.” Stores near rural schools tended to have the lowest availability of individual items. However, some items—notably, 12 of the 17 fresh fruits—were found in a higher percentage of rural stores than in stores near low-income urban, or low- and high-income urban, schools. Three of the fruits (grapefruits, oranges, and pears) were found in significantly more rural stores than in stores near low-income urban schools.

Table 2.

Availability of Healthy Snack Foods and Beverages in Stores Near High-Income Urban, Low-Income Urban, and Rural Elementary and Middle Schools, Oregon, 2012

	Percent of stores with product available (n)			P value (across locations)^a
	High-income urban (n=41)	Low-income urban (n=30)	Rural (n=14)	High-income urban vs. low-income urban	High-income urban vs. rural	Low-income urban vs. rural
Healthy beverages
Water without flavoring, additives, carbonation, or caffeine	90.2 (37)	96.7 (29)	100 (14)	0.30	0.22	0.49
Low-fat (1%) milk, 8-oz portion	12.2 (5)	3.3 (1)	0	0.18	0.17	0.49
Nonfat milk, 8-oz portion	2.4 (1)	0	0	0.39	0.56	N/A
1% or nonfat flavored milk, 8-oz portion	12.2 (5)	3.3 (1)	0	0.18	0.17	0.49
Beverages not found in any location included 100% fruit juice in 4-ounce portions and soy milk in 8-ounce portions.
Healthy snacks^b
Chips	24.4 (10)	13.3 (4)	0	0.25	0.04	0.15
Crackers	2.4 (1)	0	0	0.39	0.56	N/A
Nuts and seeds	75.6 (31)	76.7 (23)	92.9 (13)	0.92	0.16	0.19
Graham/animal crackers	0	6.7 (2)	0	0.09	N/A	0.32
Granola bars	75.6 (31)	63.3 (19)	64.3 (9)	0.26	0.41	0.95
Yogurt	56.1 (23)	23.3 (7)	42.9 (6)	0.006	0.39	0.19
Applesauce, unsweetened	12.2 (5)	0	7.1 (1)	0.05	0.60	0.14
Other canned/bottled fruit	46.3 (19)	20.0 (6)	0	0.02	0.002	0.07
Dried fruit with no added sugar	43.9 (18)	13.3 (4)	0	0.006	0.003	0.15
Snacks not found in any location included chex mix, pretzels, rice cakes, popcorn, trail mix, cookies, bagels, muffins, and popsicles/other frozen desserts.
Fresh fruits
Apple	48.8 (20)	36.7 (11)	64.3 (9)	0.31	0.32	0.09
Apricot	12.2 (5)	10.0 (3)	0	0.77	0.17	0.22
Banana	43.9 (18)	40.0 (12)	21.4 (3)	0.74	0.14	0.23
Blueberries	17.1 (7)	6.7 (2)	21.4 (3)	0.19	0.72	0.15
Cherries	12.2 (5)	0	0	0.05	0.17	N/A
Grapefruit	22.0 (9)	6.7 (2)	28.6 (4)	0.08	0.61	0.05
Grapes	4.9 (2)	3.3 (1)	14.3 (2)	0.75	0.24	0.18
Cut-up melon	34.2 (14)	10.0 (3)	0	0.02	0.01	0.22
Nectarine	22.0 (9)	10.0 (3)	14.3 (2)	0.18	0.54	0.68
Orange	39.0 (16)	23.3 (7)	64.3 (9)	0.16	0.10	0.009
Peach	22.0 (9)	13.3 (4)	14.3 (2)	0.35	0.54	0.93
Pear	22.0 (9)	6.7 (2)	35.7 (5)	0.08	0.31	0.01
Cut-up pineapple	24.4 (10)	3.3 (1)	7.1 (1)	0.02	0.16	0.57
Plum	24.4 (10)	10.0 (3)	21.4 (3)	0.12	0.82	0.30
Strawberries	7.3 (3)	3.3 (1)	7.1 (1)	0.47	0.98	0.57
Mixed fresh fruit (i.e., fruit salad)	41.5 (17)	10.0 (3)	0	0.004	0.004	0.22
Other ready-to-eat and single-portion fresh fruit (e.g., kiwi, figs)	34.2 (14)	13.3 (4)	35.7 (5)	0.05	0.92	0.09
Fresh vegetables
Broccoli florets	4.9 (2)	0	0	0.22	0.40	N/A
Carrots (baby)	12.2 (5)	6.7 (2)	0	0.44	0.17	0.32
Cauliflower florets	2.4 (1)	0	0	0.39	0.56	N/A
Celery sticks	7.3 (3)	0	0	0.13	0.30	N/A
Cherry tomatoes	22.0 (9)	16.7 (5)	0	0.58	0.06	0.10
Mixed fresh vegetables	12.2 (5)	6.7 (2)	0	0.44	0.17	0.32
Other ready-to-eat and single-portion fresh vegetables (e.g., snap peas)	12.2 (5)	6.7 (2)	14.3 (2)	0.44	0.84	0.41

Bold typeface denotes p value ≤0.05, indicating statistical significance.

p values were determined using chi-squared tests.

A “healthy” snack was defined as meeting the following Institute of Medicine nutrition standards: ≤200 calories per portion as packaged with ≤35% of total calories from fat; <10% of total calories from saturated fats, zero trans fat, and ≤35% of calories from total sugars (except for yogurt with ≤30 g of total sugars per 8-oz portion); and ≤200 mg sodium.¹⁷

oz, ounce; N/A, not applicable.

It is important to note, however, that overall availability of healthy items was low in all locations. Healthy beverages and fresh vegetables were especially limited. With the exception of plain bottled water, healthy beverages were observed in only 0–12.2% of stores, and fresh vegetables were found in 0–22.0% of stores. Healthier processed snacks and fresh fruits were somewhat more common. However, 9 of 18 snacks assessed were not found in any store and, other than apples and oranges, fresh fruits were observed in ≤43.9% of stores.

Table 3 shows the mean sum scores by food category and for all food and beverage items combined for each location and comparisons across locations. Stores near high-income urban schools had significantly higher scores for healthier processed snacks, fresh fruits, and all items combined than stores near low-income urban schools, as well as significantly higher scores for fresh vegetables (and scores that trended toward being significantly higher for processed snacks and all items combined) than stores near rural schools. There were no significant differences in scores between stores in low-income urban and rural sites nor were there any significant differences in scores for healthy beverages across the three locations.

Table 3.

Mean Number of Healthy Items Per Food Category and for All Foods/Beverages Combined Across Stores Near High-Income Urban, Low-Income Urban, and Rural Elementary and Middle Schools, Oregon, 2012

	Beverages	Snacks	Fresh fruits	Fresh vegetables	All foods/ beverages
Possible range	0–6	0–18	0–17	0–7	0–48
Mean for all stores within each location
High-income urban (n=41)	1.17	2.34	5.34	0.73	9.59
Low-income urban (n=30)	1.03	1.83	2.4	0.37	5.63
Rural (n=14)	1.0	2.0	3.57	0.14	6.71
p value (across locations)^a
High-income urban vs. low-income urban	0.31	0.04	0.009	0.16	0.009
High-income urban vs. rural	0.13	0.10	0.28	0.01	0.08
Low-income urban vs. rural	0.66	0.39	0.33	0.21	0.47

Bold typeface denotes p value ≤0.05, indicating statistical significance.

p values were determined using t-tests.

Discussion

There are two principal findings from this study. First, availability of healthy snack foods and beverages was limited in stores near schools in all three locations. Similar to earlier research, most of the items assessed were either not available or were found in only a small percentage of stores.^10–13 However, the second principal finding was that these limitations were more severe in stores proximal to low-income urban and rural schools. This result is consistent with a previous study that found fewer healthy foods and beverages in stores near low-income schools than in stores near high-income schools.¹³

Overall, stores near rural schools had the lowest availability of healthy snack foods and beverages. In particular, the range of healthy items available within each food category was notably less in the rural stores than in stores in either urban location. Also, availability of individual items was generally lowest in the rural stores. However, an exception to this pattern was in regard to fresh fruits, most of which were found more often in the rural stores than in stores near low-income urban, and even some high-income urban, schools. One explanation for this finding might be that, compared to the urban sites, a higher percentage of stores in the rural location were grocery stores. Also, the convenience stores in the rural sample were often the only food stores in their communities and may have carried more fruits in order to meet the needs of their customers who did not have easy access to larger food stores. However, if this was true, it is unclear why other healthy products, such as fresh vegetables, were not also more available in rural stores. Further studies are needed to better understand the differences in healthy food availability across rural and urban locations.

To our knowledge, this is the first study to compare availability of healthy snack foods and beverages in stores proximal to high-income urban, low-income urban, and rural schools. As such, it makes an important contribution to the sparse literature on food environments relevant to children. One strength of this study was the use of direct measurement to assess food availability in the stores. This approach has only infrequently been used because it is time and labor intensive.^10,18 However, this study also has several limitations. The sample size of stores was fairly small, especially in the rural site. Also, the percent of students eligible for free or reduced-price lunch in Portland schools was not a precise indicator of neighborhood socioeconomic status because, at the time the data were collected, children in this city were not required to attend their neighborhood school. Both of these limitations may have reduced our ability to detect significant differences across locations. Also, the timing of data collection may have influenced the results. For example, data were collected over a period of 3 months (August through October) and seasonality could have affected availability of some foods, especially fresh produce. However, the rural stores were surveyed last and yet had higher availability of several fresh fruits. Likewise, the Portland stores were surveyed in August before schools were in session, which may have affected their food inventories. In addition, data were not collected on product pricing or placement nor on product promotion within the store, factors that may influence a child's purchasing decisions.^19–21 Finally, the sample was limited to stores in Portland and two rural counties in Oregon and may not be representative of stores in other areas.

A primary barrier for store owners to stocking healthier foods is lack of customer demand for these products.^22,23 Thus, interventions that target both access to healthy foods (supply) and selection of these foods (demand) are needed.²⁴ One strategy that could improve the supply of and demand for healthier snack food and beverages in stores near schools is to engage youth in working with store owners to select and market these products. Through their participation, youth can help to ensure that selected items and their associated marketing will appeal to young customers, which, in turn, may increase the likelihood that changes in the store's inventory will be profitable and sustainable.²⁵ Youth can also promote the healthy products outside of the store to their peers and families, which may further increase the popularity of these items. In addition, when youth are involved in activities to improve the healthfulness of their food environment, they may also improve their own eating habits and encourage their friends and families to make healthier choices. Furthermore, store owners may be more receptive to making changes in their stores if the youth themselves request these. However, store owners may also need assistance in procuring healthy foods, such as fresh produce, in appealing, single-serving packages, as well as subsidized loans or financial incentives for equipment or store modification. Such strategies may be particularly important for stores in rural and low-income settings.

Conclusions

The results of this study suggest that efforts to promote healthier snack choices among children, especially those who attend rural or low-income urban schools, may be hindered by the lack of healthy foods and beverages in stores near schools. Given that children frequent these stores to purchase snacks, efforts to increase the availability of healthy products and market these to children should be a priority.

Footnotes

Acknowledgments

This study was supported with a grant from the Betty Gray Rural Health Development Fund at Oregon Health & Science University School of Nursing (Portland, OR).

Author Disclosure Statement

No competing financial interests exist.

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