Select Food Group Intake of US Children Aged 2 to 4 Years by WIC Participation Status and Income

Published:November 19, 2020DOI:https://doi.org/10.1016/j.jand.2020.07.027

      Abstract

      Background

      Food group and nutrient priorities for Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) Food Package IV for children aged 2 to 4 years were described in the 2017 review of the WIC Food Package. Research has evaluated priority nutrient intake, but priority food group intake remains unknown.

      Objectives

      To compare mean intake of priority food groups/subgroups of WIC children to WIC-eligible nonparticipants and higher income children. Further, we hoped to assess differences in percent contribution of food subgroups to total food group intake by WIC participation status and income.

      Design

      Cross-sectional study conducted using data from the 2011-14 National Health and Nutrition Examination Survey.

      Participants/setting

      One thousand forty-seven children aged 2 to 4 years.

      Main outcome measures

      Mean intake reported in cup equivalents and ounce equivalents. We also looked at mean percent that food subgroups contributed to total intake within a food group. Analyses were performed for high and low priority food groups/subgroups: high = seafood, total vegetables, dark green vegetables, red/orange vegetables, whole grains, and nuts/seeds/soy; low = total starchy vegetables, other vegetables, legumes computed as vegetables, total dairy, and total protein foods.

      Statistical analyses performed

      Multivariable linear regression analysis was used evaluate the relationship between income/WIC participation and mean intake/percent food subgroups contributed to total food group intake.

      Results

      Among low-income WIC-eligible children, participation in WIC was associated with greater mean intake of red/orange vegetables (0.18 ± 0.03 vs 0.01 ± 0.06 c equivalents; P < 0.05) and legumes (0.07 ± 0.01 vs 0.01 ± 0.02 c equivalents; P < 0.01). No differences in mean intake were observed between WIC children and higher income children. Grain intake of WIC children was composed of a higher percentage of whole grains (19.1% ± 1.6% vs 13.2% ± 1.5%; P < 0.01) compared with higher income children. The percent vegetable subgroups contributed to total vegetable intake varied by income; no differences were observed for dairy or protein subgroups.

      Conclusions

      Among low-income children, participation in WIC was associated with greater intake of certain vegetables. Participation in WIC may also help close the diet quality gap between low-income and higher income children for priority foods targeted by the WIC food package. Future research should explore socioeconomic disparities in intake of nutrient-poor foods.

      Keywords

      The Continuing Professional Education (CPE) quiz for this article is available for free to Academy members through the MyCDRGo app (available for iOS and Android devices) and through www.jandonline.org (click on “CPE” in the menu and then “Academy Journal CPE Articles”). Log in with your Academy of Nutrition and Dietetics or Commission on Dietetic Registration username and password, click “Journal Article Quiz” on the next page, then click the “Additional Journal CPE quizzes” button to view a list of available quizzes. Non-members may take CPE quizzes by sending a request to [email protected] . There is a fee of $45 per quiz (includes quiz and copy of article) for non-member Journal CPE. CPE quizzes are valid for 3 years after the issue date in which the articles are published.
      Research Question: How does intake of priority food groups/subgroups among Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) children aged 2 to 4 years compare to WIC-eligible nonparticipants and higher income children?
      Key Findings: Among low-income WIC-eligible children, participation in WIC was associated with greater intake of certain vegetables (red/orange and legumes). No differences in mean intake were observed between WIC children and higher income children. The percent that vegetable and grain subgroups contributed to total vegetable/grain intake varied by income.
      The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) is a federal nutrition assistance program that serves pregnant, breastfeeding, and postpartum women, infants, and children up to their fifth birthday who are at nutritional risk and live in low-income households (<185% poverty-income ratio [PIR]).
      • Oliveira V.
      • Frazao E.
      The WIC Program: Background, trends, and economic issues, 2015 edition. Economic Information Bulletin No. EIB-134.
      The program provides nutrient-dense foods/beverages, nutrition education, and referrals to social and medical services. WIC foods for children aged 2 to 4 years include cereal, other whole-grain products (eg, bread and tortillas), 100% juice, fruits and vegetables, milk or qualified milk substitutes, cheese, yogurt, or evaporated milk or buttermilk, eggs, and legumes.
      WIC Food Packages: Maximum monthly allowances.
      It is important to understand the influence of WIC foods and WIC participation on child diet quality. Research has shown that dietary intake of WIC participants has improved over time,
      • Zimmer M.C.
      • Vernarelli J.A.
      Changes in nutrient and food group intake among WIC children and women, findings from the 2005-2008 and 2011-2014 NHANES.
      and these changes may be largely due to the 2009 WIC food package revisions. The revised food package was associated with improvements in WIC participant diet quality
      • Schultz D.J.
      • Byker Shanks C.
      • Houghtaling B.
      The impact of the 2009 Special Supplemental Nutrition Program for Women, Infants, and Children Food Package Revisions on participants: A systematic review.
      ,
      • Tester J.M.
      • Leung C.W.
      • Crawford P.B.
      Revised WIC Food Package and Children’s Diet Quality.
      and lower childhood obesity rates.
      • Daepp M.I.G.
      • Gortmaker S.L.
      • Claire Wang Y.
      • Long M.W.
      • Kenney E.L.
      WIC food package changes: Trends in childhood obesity prevalence.
      The 2017 Review of the WIC Food Package identified nutrient and food group/subgroup priorities for aligning the WIC food package with current dietary guidance,
      Dietary Guidelines for Americans 2015-2020.
      and suggested potential actions for future food package revisions.
      Dietary intake of infants and toddlers younger than age 2 years has been the focus of recent WIC research due to the growing demand to address the relationship between early child nutrition and health outcomes throughout the life span,
      US Dept of Agriculture, Food and Nutrition Service. Pregnancy and birth to 24 months.
      and the expansion of the Dietary Guidelines to include recommendations for birth through age 24 months.
      Dietary Guidelines for Americans. Work under way.
      Recent WIC research has evaluated diet quality,
      • Au L.E.
      • Gurzo K.
      • Paolicelli C.
      • Whaley S.E.
      • Weinfield N.S.
      • Ritchie L.D.
      Diet quality of US infants and toddlers 7-24 months old in the WIC Infant and Toddler Feeding Practices Study-2.
      food/beverage intake,
      • Hamner H.C.
      • Paolicelli C.
      • Casavale K.O.
      • Haake M.
      • Bartholomew A.
      Food and beverage intake from 12 to 23 months by WIC status.
      and contribution of WIC foods to overall diet
      • Au L.E.
      • Paolicelli C.
      • Gurzo K.
      • et al.
      Contribution of WIC-eligible foods to the overall diet of 13- and 24-month-old toddlers in the WIC Infant and Toddler Feeding Practices Study-2.
      among infants and toddlers younger than age 24 months.
      WIC children aged 2 to 4 years are understudied, yet one-quarter of all US children aged 2 to 4 years participate in WIC.
      • Oliveira V.
      • Frazao E.
      The WIC Program: Background, trends, and economic issues, 2015 edition. Economic Information Bulletin No. EIB-134.
      Given that WIC coverage rates decline as children get older,
      WIC 2016 eligibility and coverage rates.
      it is especially important to understand dietary intake of older WIC children, and how the 2- to 4-year old food package can support dietary behaviors. One study has assessed usual intake of priority nutrients for children younger than age 4 years,
      • Jun S.
      • Catellier D.J.
      • Eldridge A.L.
      • Dwyer J.T.
      • Eicher-Miller H.A.
      • Bailey R.L.
      Usual nutrient intakes from the diets of US children by WIC participation and income: Findings from the Feeding Infants and Toddlers Study (FITS) 2016.
      but priority food group/subgroup intake of WIC children remains unknown. Therefore, this study explored priority food group/subgroup intake of US children aged 2 to 4 years by WIC participation status and income. The objectives were to compare mean intake of WIC children to WIC-eligible nonparticipants and higher income group children; and to assess differences in percent food subgroups comprised total intake within a food group by WIC participation status and income.

      Materials and Methods

      Study Design

      This cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey (NHANES). NHANES participants complete physical examinations and comprehensive questionnaires at NHANES Mobile Examination Centers that travel the country according to a complex, multistage probability cluster-sampling design. NHANES, and its related nutritional component, What We Eat In America, are designed to monitor the health and nutritional status of noninstitutionalized civilians in the United States.
      • Ahluwalia N.
      • Dwyer J.
      • Terry A.
      • Moshfegh A.
      • Johnson C.
      Update on NHANES dietary data: Focus on collection, release, analytical considerations, and uses to inform public policy.
      The National Center for Health Statistics Research Ethics Review Board reviewed and approved all study protocols for NHANES. Because all NHANES data are de-identified and do not collect sensitive information, this study was exempt from further review by our institutional review board.
      Dietary information was collected during NHANES interview by trained interviewers who performed 24-hour recall assessments using the US Department of Agriculture Automated Multiple Pass Method.
      • Moshfegh A.J.
      • Rhodes D.G.
      • Baer D.J.
      • et al.
      The US Department of Agriculture Automated Multiple-Pass Method reduces bias in the collection of energy intakes.
      A parent or caretaker served as proxy respondent for children younger than age 6 years, so the present analysis represents child dietary intake reported via proxy. The NHANES collects 2 days of diet recall. The first recall is collected in-person at the mobile examination center, and the second is collected via telephone 3 to 10 days later.
      • Ahluwalia N.
      • Dwyer J.
      • Terry A.
      • Moshfegh A.
      • Johnson C.
      Update on NHANES dietary data: Focus on collection, release, analytical considerations, and uses to inform public policy.
      The first day of dietary recall was used for this study. Dietary data were processed using the US Department of Agriculture Food Patterns Equivalents Database (FPED), which converts reported food and beverage items into servings of disaggregated food pattern components (eg, total starchy vegetables and red and orange vegetables), allowing for assessment of subgroups consumed within a food group. Further information on the FPEDs can be found in the user guide.
      • Bowman S.
      • Clemens J.
      • Friday J.
      • Lynch K.
      • Moshfegh A.
      Food Patterns Equivalents Database 2013-14: Methodology and user guide.
      The What We Eat In America-linked FPED Statstical Analysis System files containing the total amounts of each of the 37 components from foods and beverages reported by respondents on Day 1 were utilized.

      Sample

      Data from two cycles (2011-12 and 2013-14) of the NHANES were combined for the present study to create a sample of the most current national dietary estimates that included information on WIC participation status and were available during the time of analysis. Children with missing/incomplete dietary data (n = 89) or with unreliable Day 1 dietary recall status (n = 34), and children who consumed breast milk (n = 15), were excluded. Children were categorized into three groups based upon WIC participation status and income. WIC children were defined as answering yes to both of the following questions: “Did [child] receive benefits from WIC; that is, the Women, Infants, and Children program, in the past 12 months?” and, “Is [child] now receiving benefits from the WIC program?” WIC-eligible nonparticipants were defined as children aged 2 to 4 years who lived in households that were income-eligible for WIC at the time of NHANES interview (≤185% PIR) but answered no to the question about receiving WIC benefits during the past 12 months. Higher income children were defined as children aged 2 to 4 years who lived in households that were not income-eligible for WIC at the time of NHANES interview (>185% PIR).

      Main Outcome Measure

      For the first study objective, the primary measure was mean intake of priority food groups/subgroups, reported in cup equivalents or ounce equivalents. For the second objective, the outcome was the relative proportion (reported as percentage value) that food subgroups contributed to total intake within a food group. For both objectives, the variables analyzed represent food group/subgroup priorities for WIC Food Package IV for children aged 2 to <5 years, as described in the National Academies of Sciences, Engineering, and Medicine (NASEM) 2017 Review of the WIC Food Package.
      High priority food groups and subgroups were defined as consumed below recommended levels in more than 75% of WIC children aged 2 to 4 years. These included total vegetables, dark green vegetables, total red and orange vegetables, whole grains, seafood, and nuts/seeds/soy.
      Lower priority food group and subgroups were those for which intake was below the recommended amount in 50% to <75% of WIC children. These included total starchy vegetables, other vegetables, total dairy, total protein foods, and beans/peas computed as vegetables.
      The food group priorities are summarized in Table 1, available at www.jandonline.org. Only the FPEDs corresponding to the priority food groups/subgroups outlined in Table 1, available at www.jandoinline.org, were analyzed.

      Statistical Analysis

      Sociodemographic characteristics (including age, sex, race/ethnicity, household income, and household size) were assessed by Wald χ2 test. Race/ethnicity, age, sex, and total energy intake were included as covariates in the multivariable linear regression model. The NHANES Day 1 dietary sample weight was also included in the regression model. The same model was used for both objectives. For objective one, mean intake was assessed for all three groups (WIC children, WIC-eligible nonparticipants, and higher income group children) and estimates for WIC children were compared with WIC-eligible nonparticipants and higher income children. For objective two, the population proportion
      • Krebs-Smith S.M.
      • Kott P.S.
      • Guenther P.M.
      Mean proportion and population proportion: Two answers to the same question?.
      that food subgroups contributed to total intake within a food group was calculated in accordance with the multistep National Center for Health Statistics Data Presentation Standards for Proportions.
      • Parker J.D.
      • Talih M.
      • Malec D.J.
      • et al.
      National Center for Health Statistics data presentation standards for proportions.
      Multivariable linear regression analysis was used to examine differences between WIC children compared with WIC-eligible nonparticipants and higher income children. All data were analyzed using SAS 9.4 survey procedures

      SAS [computer program]. Version 9.4. SAS Institute Inc, Cary, NC; 2017.

      with appropriate weighting and clustering to account for the differential probabilities of selection, nonresponse, and oversampling associated with the multistage, probability cluster-sampling design of the NHANES. Statistical significance was determined at P < 0.05.

      Results

      In NHANES 2011-14, there were 1,047 children aged 2 to 4 years with complete, reliable Day 1 dietary recall status who did not consume breast milk. Of the 1,047 children, 360 (34.4%) lived in higher income households that were not eligible for the WIC program (>185% PIR). There were 224 children (21.4%) who were WIC-eligible but not participating in the program, and 463 (44.2%) who were participating in WIC at the time of NHANES interview. Additional sample characteristics are displayed in Table 2.
      Table 2Characteristics of children aged 2 to 4 years (N = 1,047) in the 2011-14 National Health and Nutrition Examination Survey
      CharacteristicHigher income children (n = 360)WIC
      WIC = Special Supplemental Nutrition Program for Women, Infants, and Children. WIC-eligible nonparticipants were defined as children aged 2 to <5 years of age who were living in households with income <185% of the federal poverty-income ratio (PIR) but not participating in the WIC program at the time of NHANES interview.
      -eligible nonparticipants (n = 224)
      WIC children (n = 463)
      NWeighted %95% CINWeighted %95% CINWeighted %95% CI
      Sex
      Male17249.944.6-55.311052.142.6-61.623148.340.8-55.7
      Female18850.144.7-55.411447.938.4-57.423251.744.3-59.2
      Race/ethnicity
      Non-Hispanic White12169.361.5-77.05953.640.5-66.76426.7
      P < 0.001.
      16.2-37.1
      Non-Hispanic Black566.54.5-8.47417.610.3-24.815221.514.2-28.8
      Hispanic7612.37.8-16.96322.613.2-32.120243.934.2-53.7
      Other/Mixed10711.97.0-16.8286.13.4-8.9457.94.9-10.9
      Age (y)
      P < 0.05.
      214031.126.8-35.37328.320.8-35.821138.534.2-42.8
      310936.830.3-43.47136.525.7-47.313232.128.1-36.1
      411132.125.5-38.78035.225.6-44.912029.424.8-34.0
      Family Income (PIR)
      Family income reported as the PIR, which is the ratio of family income to poverty guidelines. PIR is provided in the NHANES based on self-reported income. Individuals living in households <185% PIR are income-eligible for WIC.1
      <130%0017271.563.8-79.336477.071.3-82.6
      130%-185%005228.520.7-36.26111.98.8-15.0
      >185%3601000038
      Thirty-eight WIC participants had self-reported income >185% PIR, which may be due to overestimation of income, change in income between WIC certification appointments, adjunctive eligibility (eg, participation in Medicaid), among other reasons.
      11.15.8-16.4
      a WIC = Special Supplemental Nutrition Program for Women, Infants, and Children. WIC-eligible nonparticipants were defined as children aged 2 to <5 years of age who were living in households with income <185% of the federal poverty-income ratio (PIR) but not participating in the WIC program at the time of NHANES interview.
      b Family income reported as the PIR, which is the ratio of family income to poverty guidelines. PIR is provided in the NHANES based on self-reported income. Individuals living in households <185% PIR are income-eligible for WIC.
      • Oliveira V.
      • Frazao E.
      The WIC Program: Background, trends, and economic issues, 2015 edition. Economic Information Bulletin No. EIB-134.
      d Thirty-eight WIC participants had self-reported income >185% PIR, which may be due to overestimation of income, change in income between WIC certification appointments, adjunctive eligibility (eg, participation in Medicaid), among other reasons.
      P < 0.05.
      ∗∗∗ P < 0.001.
      Table 3 displays reported intake of priority food groups/subgroups on a given day for US children aged 2 to 4 years by WIC participation status and income, shown as mean intake ± standard error. Among low-income WIC-eligible children, participation in WIC was associated with greater intake of certain vegetables. Compared with WIC-eligible nonparticipants, WIC children had significantly greater intake of red and orange vegetables (0.18 ± 0.03 vs 0.01 ± 0.06 c equivalents; P < 0.05) and legumes computed as vegetables (0.07 ± 0.01 vs 0.01 ± 0.02 c equivalents; P < 0.01). No differences in mean intake were observed between WIC children and higher income children, demonstrating comparable intake between the two groups for the priority food groups/subgroups analyzed.
      Table 3Mean intake among US children aged 2 to 4 years in the National Health and Examination Survey by Special Supplemental Nutrition Program in Women, Infants, and Children (WIC) Participation Status and Income, 2011-14 (N = 1,047)
      Mean intake is reported as least-square means with standard error, representing the population’s mean intake on a given day. Data are from one 24-hour recall reported for the child by a proxy. Estimates are reported in ounce equivalents and cup equivalents.
      Food group category
      Food categories represent higher and lower priority food groups/subgroups as described in Table 1, available at www.jandonline.org, and the 2017 Review of the WIC Food Package.8 Food categories appear in priority order from highest priority (largest percentage of WIC-participating children consuming less than the recommended intake) to lowest priority (smallest percentage of WIC-participating children consuming less than the recommended intake).
      Higher Income Children (n = 360)WIC-Eligible Nonparticipants (n = 224)WIC Children (n = 463)Recommended amount
      Recommendations represent Dietary Guidelines for Americans 2015-20 recommendations based on a 1,300 kcal food pattern, as presented in the 2017 Review of the WIC Food Package, Tables 5 through 10.8 Recommendations made on a per-week basis have been converted to a per-day basis, to promote comparability between recommendations and the results from this study.
      mean ± standard error
      Higher priority
      Seafood (oz eq)0.03 ± 0.07< 0.01 ± 0.100.15 ± 0.060.71 oz eq/d
      Total vegetables, excluding legumes (c eq)0.52 ± 0.080.39 ± 0.130.55 ± 0.071.5 c eq/d
      Dark green vegetables (c eq)0.01 ± 0.05< 0.01 ± 0.040.05 ± 0.030.14 c eq/d
      Whole grains (oz eq)0.53 ± 0.070.45 ± 0.090.62 ± 0.062.25 oz eq/d
      Total red and orange vegetables (c eq)0.23 ± 0.050.01 ± 0.06
      P < 0.05; indicates statistically significance difference in mean intake compared with children receiving WIC benefits (WIC children).
      0.18 ± 0.030.43 c eq/d
      Nuts, seeds, soy (c eq)0.30 ± 0.140.16 ± 0.130.17 ± 0.080.36 oz eq/d
      Lower priority
      Total starchy vegetables (c eq)0.12 ± 0.050.23 ± 0.070.19 ± 0.050.50 c eq/d
      Other vegetables (c eq)0.17 ± 0.030.08 ± 0.020.13 ± 0.020.36 c eq/d
      Total dairy (c eq)1.93 ± 0.122.1 ± 0.261.8 ± 0.102.50 c eq/d
      Total protein foods (oz eq)1.96 ± 0.162.30 ± 0.232.13 ± 0.083.50 oz eq/d
      Legumes computed as vegetables (c eq)0.03 ± 0.020.01 ± 0.02
      P < 0.01; indicates statistically significance difference in mean intake compared with children receiving WIC benefits (WIC children).
      0.07 ± 0.010.07 c eq/d
      a Mean intake is reported as least-square means with standard error, representing the population’s mean intake on a given day. Data are from one 24-hour recall reported for the child by a proxy. Estimates are reported in ounce equivalents and cup equivalents.
      b Food categories represent higher and lower priority food groups/subgroups as described in Table 1, available at www.jandonline.org, and the 2017 Review of the WIC Food Package.
      Food categories appear in priority order from highest priority (largest percentage of WIC-participating children consuming less than the recommended intake) to lowest priority (smallest percentage of WIC-participating children consuming less than the recommended intake).
      c Recommendations represent Dietary Guidelines for Americans 2015-20 recommendations based on a 1,300 kcal food pattern, as presented in the 2017 Review of the WIC Food Package, Tables 5 through 10.
      Recommendations made on a per-week basis have been converted to a per-day basis, to promote comparability between recommendations and the results from this study.
      P < 0.05; indicates statistically significance difference in mean intake compared with children receiving WIC benefits (WIC children).
      ∗∗ P < 0.01; indicates statistically significance difference in mean intake compared with children receiving WIC benefits (WIC children).
      Table 4 displays the percentage that food subgroups contributed to total intake within a food group. No differences were observed between WIC children and WIC-eligible nonparticipants. WIC children and higher income children differed in the percentage that vegetable subgroups contributed to total vegetable intake. Compared with higher income children, total vegetable intake of WIC children was composed of a lower percentage of red and orange vegetables (34.5 ± 3.2 vs 49.1 ± 3.5%; P < 0.05), larger percentage of total starchy vegetables (34.4 ± 3.5 vs 18.2 ± 3.8%; P < 0.05), and smaller percentage of other vegetables (24.8% ± 1.8% vs 30.5% ± 2.4%, P < 0.05). Differences were also observed for grain subgroups. Compared with higher income children, total grain intake of WIC children was composed of a higher percentage of whole grains (19.1% ± 1.6% vs 13.2% ± 1.5%; P < 0.01) and lower percentage of refined grains (81.0% ± 1.6% vs 86.9% ± 1.6%; P < 0.01). The percent contributions of dairy subgroups to total dairy intake, and the percent contributions of priority protein subgroups (seafood, nuts/seeds/soy) to total protein intake, were similar by WIC participation status and income.
      Table 4Percent food subgroups contribution to total food group intake among US Children aged 2 to 4 years in the National Health and Examination Survey by Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) participation status and income, 2011-14 (N = 1,047)
      Food group category
      Food categories represent higher and lower priority food groups/subgroups as described in Table 1, available online at www.jandonline.org, and the 2017 Review of the WIC Food Package.8
      Higher Income Children (n = 360)WIC-Eligible Nonparticipants (n = 224)WIC Children (n = 463)
      mean % ± standard error
      Least-square means are presented with standard error, representing the mean percent selected food subgroups contribute to total food group intake. Data are from one 24-hour recall reported for the child by a proxy.
      Vegetable intake
      Dark green3.3 ± 3.47.7 ± 5.46.4 ± 1.9
      Total red and orange49.1 ± 3.5
      P < 0.05; indicates statistically significance difference compared to children receiving WIC benefits (WIC children).
      35.8 ± 5.634.5 ± 3.2
      Total starchy18.2 ± 3.8
      P < 0.05; indicates statistically significance difference compared to children receiving WIC benefits (WIC children).
      37.5 ± 5.534.4 ± 3.5
      Other vegetables30.5 ± 2.4
      P < 0.05; indicates statistically significance difference compared to children receiving WIC benefits (WIC children).
      18.7 ± 4.224.8 ± 1.8
      Dairy intake
      Milk68.1 ± 3.570.4 ± 5.272.7 ± 2.2
      Yogurt8.1 ± 1.66.6 ± 2.15.1 ± 1.0
      Cheese22.5 ± 3.021.8 ± 4.920.1 ± 1.5
      Grain intake
      Whole grains13.2 ± 1.5
      P < 0.01; indicates statistically significance difference compared to children receiving WIC benefits (WIC children).
      14.6 ± 1.819.1 ± 1.6
      Refined grains86.9 ± 1.6
      P < 0.01; indicates statistically significance difference compared to children receiving WIC benefits (WIC children).
      85.4 ± 1.881.0 ± 1.6
      Protein foods
      Seafood1.9 ± 1.32.6 ± 2.43.5 ± 1.2
      Nuts, seeds, soy14.8 ± 2.89.8 ± 2.58.9 ± 1.5
      a Food categories represent higher and lower priority food groups/subgroups as described in Table 1, available online at www.jandonline.org, and the 2017 Review of the WIC Food Package.
      b Least-square means are presented with standard error, representing the mean percent selected food subgroups contribute to total food group intake. Data are from one 24-hour recall reported for the child by a proxy.
      P < 0.05; indicates statistically significance difference compared to children receiving WIC benefits (WIC children).
      ∗∗ P < 0.01; indicates statistically significance difference compared to children receiving WIC benefits (WIC children).

      Discussion

      Discussion of a social gradient in diet and health dates back to the Great Depression era,
      • Boyd J.
      Food, Health and Income: Report on a Survey of Adequacy of Diet in Relation to Income.
      and persists in the public health nutrition literature today. Socioeconomic inequalities in dietary intake are well documented,
      • Hiza H.A.B.
      • Casavale K.O.
      • Guenther P.M.
      • Davis C.A.
      Diet quality of Americans differs by age, sex, race/ethnicity, income, and education level.
      although research continues to emerge demonstrating the positive role the WIC program plays in supporting diet quality of low-income children. Previous research has shown that, among WIC participants aged 24 months, continued participation in WIC is positively associated with Healthy Eating Index scores, including a higher component score for total vegetables.
      • Weinfield N.S.
      • Borger C.
      • Au L.E.
      • Whaley S.E.
      • Berman D.
      • Ritchie L.D.
      Longer Participation in WIC Is Associated with Better Diet Quality in 24-Month-Old Children.
      The findings from the present study demonstrate that, among low-income WIC-eligible children aged 2 to 4 years, participation in the WIC program was positively associated with intake of certain vegetables (red/orange and legumes). Therefore, participation in WIC may support vegetable intake among older (aged 2 to 4 years) children as well, although additional research should be done to determine the relationship between length of WIC participation and intake.
      Participation in WIC may also help close the diet quality gap between low income and higher income children. In this study, no differences were observed in mean intake between WIC children and higher income children, suggesting that participation in WIC may help neutralize socioeconomic disparities in intake of the priority food group/subgroups targeted by the WIC food package. Previous research
      • Jun S.
      • Catellier D.J.
      • Eldridge A.L.
      • Dwyer J.T.
      • Eicher-Miller H.A.
      • Bailey R.L.
      Usual nutrient intakes from the diets of US children by WIC participation and income: Findings from the Feeding Infants and Toddlers Study (FITS) 2016.
      that explored the relationship between priority nutrient intake and WIC participation showed similar results. Among children aged 24 to 47.9 months, no differences were observed between WIC children and higher income nonparticipants for percent compliance with dietary guidelines for priority nutrients to increase (iron, vitamin D, fiber, potassium, calcium, and zinc).
      • Jun S.
      • Catellier D.J.
      • Eldridge A.L.
      • Dwyer J.T.
      • Eicher-Miller H.A.
      • Bailey R.L.
      Usual nutrient intakes from the diets of US children by WIC participation and income: Findings from the Feeding Infants and Toddlers Study (FITS) 2016.
      However, WIC children had lower compliance with guidelines for certain nutrients to limit (added sugar and sodium) compared with higher income children.
      • Jun S.
      • Catellier D.J.
      • Eldridge A.L.
      • Dwyer J.T.
      • Eicher-Miller H.A.
      • Bailey R.L.
      Usual nutrient intakes from the diets of US children by WIC participation and income: Findings from the Feeding Infants and Toddlers Study (FITS) 2016.
      It may be that participation in WIC is associated with greater intake of certain nutrient-dense foods, like vegetables, which translates to greater compliance with dietary guidance for nutrients to increase. Further research should explore the relationship between WIC participation status and intake of nonpriority food subgroups to better understand consumption of nutrient-poor foods not targeted by the WIC program. Such information would provide insight into how to neutralize differences between low and higher income children’s compliance with dietary guidelines for nutrients to limit.
      WIC benefits for produce are administered via cash value benefits (CVB), offering participants flexibility in fruit and vegetable selection. The fruit and vegetable CVB was introduced with the comprehensive 2009 WIC food package revisions, and was associated with increased fruit and vegetable purchases.
      • Andreyeva T.
      • Luedicke J.
      Incentivizing fruit and vegetable purchases among participants in the Special Supplemental Nutrition Program for Women, Infants, and Children.
      The NASEM’s 2017 Review of the WIC Food Package recommended increasing the CVB again, making it important to understand the produce varieties commonly acquired using the CVB. Although barriers to CVB redemption have been identified,
      • Bertmann F.M.W.
      • Barroso C.
      • Ohri-Vachaspati P.
      • Hampl J.S.
      • Sell K.
      • Wharton C.M.
      Women, Infants, and Children Cash Value Voucher (CVV) use in Arizona: A qualitative exploration of barriers and strategies related to fruit and vegetable purchases.
      it is unknown how this translates to produce intake. This study evaluated differences in the percent contributions various vegetable types/subgroups make to total vegetable intake, and found differences between WIC children and higher income children. However, no differences between WIC children and WIC-eligible children were observed, suggesting that although WIC children have greater intake of certain types of vegetables (red/orange and legumes), the proportions of vegetable subgroups relative to total vegetable intake are comparable.
      The NASEM report also recommended increasing the WIC whole-grain allowance or adding more whole-grain options.
      When additional whole-grain products were added to the WIC food package in 2009, WIC households’ purchase of whole grains increased,
      • Andreyeva T.
      • Luedicke J.
      Federal food package revisions: Effects on purchases of whole-grain products.
      as did intake of whole grains and related nutrients like fiber among children aged 2 to 4 years of age.
      • Zimmer M.C.
      • Vernarelli J.A.
      Changes in nutrient and food group intake among WIC children and women, findings from the 2005-2008 and 2011-2014 NHANES.
      In this study, although no differences in mean whole-grain intake were observed, total grain intake of WIC children was composed of a greater percentage of whole grains, and lower percentage of refined grains, compared with higher income children. Increases to WIC whole-grain benefits may further support intake of whole grains and priority nutrients like fiber.

      Limitations

      Although this study was able to identify associations between income/WIC participation status and mean intake/food group percentages, the cross-sectional design precludes causal inferences. Reasons why income- and age-eligible children do not participate in WIC, and when previous WIC recipients stopped participating, are not captured in the NHANES dataset and remain unknown. Although 24-hour recalls are the standard protocol for collection of individual dietary data, there are known limitations, such as recall bias and social desirability bias.
      • Subar A.F.
      • Freedman L.S.
      • Tooze J.A.
      • et al.
      Addressing current criticism regarding the value of self-report dietary data.
      Because the target sample for this analysis included children aged 2 to 4 years, recall data depended on the accuracy of reporting by a proxy respondent,
      • Ahluwalia N.
      • Dwyer J.
      • Terry A.
      • Moshfegh A.
      • Johnson C.
      Update on NHANES dietary data: Focus on collection, release, analytical considerations, and uses to inform public policy.
      and may be especially prone to recall bias. The results reported here represent population mean intake on a given day, and are therefore not an estimation of long-term usual intake.

      Conclusions

      Among low-income WIC-eligible children, participation in WIC was associated with greater intake of certain vegetables (red/orange and legumes). No differences in intake of priority food groups/subgroups were observed between WIC children and higher income children, suggesting that participation in WIC may help neutralize socioeconomic disparities in intake of the priority food groups/subgroups targeted by the WIC food package. WIC children and higher income children differed in the percentage that vegetable subgroups contributed to total vegetable intake, though percentages were similar between WIC children and WIC-eligible children. Also, total grain intake of WIC children was composed of a greater percentage of whole grains and lower percentage of refined grains compared with higher income children.

      Supplementary Materials

      Table 1Food Group Priorities and Preliminary Actions for Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) Food Package IV for children aged 2 to <5 years from the 2017 National Academies of Sciences, Engineering, and Medicine (NASEM) Review of the WIC Food Package
      The information in this table is adapted from Tables 5 through 10 in the NASEM 2017 Review of the WIC Food Package.8
      Food group% of WIC-participating children consuming less than the recommended intakePotential action
      Higher priority
      The NASEM report defined higher priority food group and subgroups as those for which intake was below the recommended amount in 75% or more of children aged 2 to <5 years.8
      Seafood100Consider adding canned fish
      Total vegetables99Consider increasing the CVV
      CVV = cash value voucher.
      Dark green vegetables94Consider increasing the CVV
      Whole grains93Consider increasing the whole-grain allowance or adding grain options
      Total red and orange vegetables90Consider increasing the CVV
      Nuts, seeds, soy77Consider reducing the amount in the food package because it is more than supplemental
      Lower priority
      The NASEM report defined lower priority food group and subgroups as those for which intake was below the recommended amount in 50% to <75% of children aged 2 to <5 years.8
      Total starchy vegetables73Consider increasing the CVV
      Other vegetables73Consider increasing the CVV
      Total dairy73Consider increasing the yogurt substitution; enhance nutrition education or use behavioral approaches to promote intake of milk already provided in the food package
      Total protein foods68Consider adding canned fish
      Beans and peas computed as vegetables59Consider reducing amount in the food package because it is more than supplemental and providing canned option to promote intake of legumes
      a The information in this table is adapted from Tables 5 through 10 in the NASEM 2017 Review of the WIC Food Package.
      b The NASEM report defined higher priority food group and subgroups as those for which intake was below the recommended amount in 75% or more of children aged 2 to <5 years.
      c CVV = cash value voucher.
      d The NASEM report defined lower priority food group and subgroups as those for which intake was below the recommended amount in 50% to <75% of children aged 2 to <5 years.

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      Biography

      M. C. Zimmer is a student, Department of Public Health, The University of Tennessee, Knoxville.
      J. A. Venarelli is an assistant professor, Department of Public Health, Sacred Heart University, Fairfield, CT.