HD: Food Security (2011)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of the study was to determine if the provision of food stamps without nutrition education improve food intake patterns.

Inclusion Criteria:

Participants or persons enrolled in:

  • Expanded Food and Nutrition Education Program (EFNEP)
  • Adult education
  • Vocational rehabilitation
  • Department of Social Services programs.

 

Exclusion Criteria:
  • People under the age of 18 years
  • People with self-reported incomes exceeding food stamp eligibility requirements
  • People reporting no income and living with their families.
Description of Study Protocol:

Recruitment

People were recruited from existing programs during their usual operating hours.

Design

  • An "ex-post facto" design was used, where data were collected from eligible participants and then data were compared between those who received food stamps and those who did not 
  • The following data were collected from study participants
    • 24-hour diet recalls
    • Demographic data
    • Food behavior and knowledge data
    • Anthropometrics
    • Blood pressure
    • Self-reported physical activity.

Blinding used

Not applicable

Intervention

Not applicable

Statistical Analysis

  • Means ± standard deviations
  • Two-sample Student T-tests
  • Chi-square analysis.
Data Collection Summary:

Timing of Measurements

Unclear

Dependent Variables

  • Dietary intake of selected nutrients
    • 24-hour diet recalls obtained by registered dietitians (RDs) or by graduate students supervised by RD
    • Recalls were analyzed using the Food Processor Plus nutrient analysis software system and compared to Recommended Dietary Allowances and Daily Reference Intakes
  • Number of food group servings
    • Food items on 24-hour recall questionnaires were sorted into food categories developed by a team of RDs and adapted from the Food Guide Pyramid
    • High-fat snack and high-sugar snack categories were added and vegetables were divided into starchy and other vegetable categories
    • Serving sizes based on the American Diabetes Association exchange list serving sizes with the exception of meat (three ounces considered a serving) and eggs (three eggs considered a serving).

Independent Variables

Food stamp recipient status (yes/no)

Other Variables

  • Demographic data
    • Collected using EFNEP Family Record Part A-Description
  • Nutrition knowledge and food preparation techniques
    • Collected using EFNEP Family Record Part B-Food and Behavior and Nutrition Knowledge
  • Food security
    • Item on EFNEP Family Record Part B
  • Body Mass Index
    • Participants weighed and measured according to accepted standards
  • Percent body fat
    • Mean of three skinfold measurements using the Brozek formula
  • Activity level
    • Self-reported.

Control Variables

None

Description of Actual Data Sample:
  • Initial N: 208 participants
    • 151 food-stamp (FS) recipients
    • 57 not food-stamp (NFS) recipients
  • Attrition (final N): Not applicable 
  • Age, years (mean ± standard deviation): Total sample: 34±12
    • FS recipients: 33±10
    • NFS recipients: 38±16
    • (NFS recipients were significantly older than FS recipients, P≤0.001)
  • Race/Ethnicity (number/percent): Total sample
    • White: (50/33%)
    • Black: (154/66%)
    • Other: (4/1%)
    • (Not significantly different between FS/NFS groups)
  • Other relevant demographics:
    • Education (number/percent):
      • Total sample:
        • Less than high school: (125/60%)
        • High school grad: (55/26%)
        • More than high school: (27/13%)
      • FS recipients:
        • Less than high school: (97/64%)
        • High school grad: (40/26%)
        • More than high school: (13/9%)
      • NFS recipients:
        • Less than high school: (28/49%)
        • High school grad: (15/26%)
        • More than high school: (14/25%)
      • (Significantly greater proportion of FS recipients did not complete high school, P≤0.01)
    • Income (number/percent)
      • Total sample:
        • <$10,000: (175/84%)
        • $10,001-$20,000: (26/13%)
        • $20,001-$30,000: (7/3%)
      • FS recipients:
        • <$10,000: (143/95%)
        • $10,001-$20,000: (4/2.5%)
        • $20,001-$30,000: (4/2.5%)
      • NSF recipients:
        • <$10,000: (32/56%)
        • $10,001-$20,000: (22/39%)
        • $20,001-$30,000: (3/5%)
      • (Significantly greater proportion of FS recipients earned <$10,000, P≤0.001)
  • Anthropometrics: Body Mass Index, kg/m2, (mean ± standard deviation)
    • Total sample: 31.5±9.7
    • FS recipients: 32.1±10.3
    • NFS recipients: 30.0± 8.0
    • (Not significantly different between FS/NFS groups)
  • Location: South Carolina.
Summary of Results:

Key Findings

  • Mean total energy intakes for both groups fell below 100% (FS: 82%; NFS: 74%) of the RDA for women 25-50 years of age. Mean intake was not significantly different between groups, although the FS recipients tended to have a greater intake.
  • FS recipients reported a greater percent of kcal intake from fat (P<0.05) and protein (P<0.01) and lower percent of kcal intake from carbohydrate (P<0.001) than NFS recipients)
  • Food intakes reported for both groups exceeded the RDA for vitamins C, thiamin, riboflavin, niacin, and vitamin B12. Mean intake of vitamin B12 was significantly higher among FS recipients than NFS recipients.
  • Intakes of vitamins A, E, and B6 and iron were below 100% of the RDA, and mean intake of vitamin D was below two-thirds of the RDA for FS and NFS recipients. These values were not significantly different between groups.
  • NFS recipients had mean intakes less than two-thirds of the RDA for vitamin E and zinc. Mean intake of zinc was significantly lower in the NFS recipients than FS recipients (P<0.05).
  • When compared to the DRIs, intakes of calcium for FS and NFS were below two-thirds; and intakes of folate were below 50% of the recommended values. These values were not significantly different between groups.

Mean Reported Dietary Intake of Selected Nutrients

Variables

Total

(N=208)

Mean±SD

FS recipients

(N=151)

Mean±SD

NFS recipients

(N=57)

Mean±SD

Total Kcals 1,766±803 1,811±831 1,682±724
Protein (percent Kcals)** 16±6 16±6 14±5
Carbohydrate (percent Kcals)*** 49±12 47±11 53±11
Fat (percent Kcals)* 36±10 37±10 34±9
Vitamin B12 (percent RDA)** 170±166 187±182 124±101
Zinc (percent RDA)* 75±45 79±46 62±40

*P≤0.05, **P≤0.01, ***P≤0.001

  • Analysis of food intake data adapted from Food Guide Pyramid categories indicated inadequate intakes for both groups for recommended numbers of servings in all categories except meats 
  • Reported intakes of meats were significantly (P<0.01) higher in FS recipients than in NFS recipients
  • Mean intakes of starchy vegetables and fruits were significantly lower (P<0.01 and P<0.05, respectively) in FS recipients than NFS recipients
  • Reported fruit and vegetable consumption (FS: 2.24 and NFS: 2.92) for both groups was below the Healthy People 2000 objective of five fruits and vegetables per day.

Mean Number of Servings Consumed

Variables

Total

(N=208)

Mean±SD

FS recipients

(N=151)

Mean±SD

NFS recipients

(N=57)

Mean±SD

Dairy 0.93±1.1   0.93±1.1  0.92±1.1 
Grains 3.87±2.5  3.98±2.7  3.6±1.9 
Starchy vegetables** 0.63±1.0  0.52±0.9  0.93±1.1 
Other vegetables 1.04±1.3  1.1±1.2  0.89±1.3 
Fruits* 0.75±1.2  0.62±1.1  1.1±1.4 
Meats** 1.88±1.3 2.02±1.3  1.50±0.92 
Fats 1.41±1.5 1.46±1.6  1.30±1.1 
High-fat snacks 0.74±1.0  0.71±0.95  0.81±1.2 
High-sugar snacks 2.78±2.3  2.70±2.2  2.90±2.5 

*P≤0.05, **P≤0.01

Other Findings

  • Mean scores for all participants on the brief nutrition knowledge pre-test were below 50% (40±24%)
  • The FS recipients scored significantly (P<0.01) lower than the NFS recipients (37±24% and 47±25%, respectively) on the behavior and nutrition knowledge pre-test.
Author Conclusion:

Although food stamp benefits increased food purchasing power, food stamps did not appear to ensure consumption of nutritionally adequate diets. In addition, the significantly lower income and educational levels of FS recipients may have contributed to their less than optimal dietary habits. Results of the present study suggest that low-income individuals in South Carolina would benefit from nutrition education.

Funding Source:
Government: South Carolina Agriculture and Forestry System, Clemson University
Reviewer Comments:

I was unable to assign a positive rating for the following reasons: First, the statistical analysis did not control for the effects of different age and educational and income levels between groups. Although, overall, the findings supported the assumption that participating in the food stamp program alone did not improve intake, we do not know if intake might have been better among more highly educated persons receiving food stamps. 

Furthermore, it seems that a multivariate analysis may have also been able to control for the effects of food insecurity and physical activity level. Also, it is not clear from the present study if nutrition knowledge is associated with better intake. It seems these multivariate analyses could have been performed with the data collected, although the sample size might have been too small for multivariate analysis. In addition, a three-day food record would have been a better measure of dietary intake than a 24-hour recall. 

Finally, data were not collected on the length of time participants had been receiving food stamps. We do not know if study participants just received their food stamps or how long they had been on the food stamp program and whether length of time on the program might influence dietary intake.