Journal Issue: Children and Poverty Volume 7 Number 2 Summer/Fall 1997
The Special Supplemental Food Program for Women, Infants, and Children (WIC)
The Special Supplemental Food Program for Women, Infants, and Children (WIC) started as a two-year pilot program in 1972 in response to growing concern about evidence of malnutrition and related health problems among low-income pregnant women and children. Over the years, WIC has expanded and now serves almost seven million women and children per month. WIC focuses on the special nutritional needs of low-income pregnant women, infants, and children, based on the assumption that insufficient nutrition during these critical development periods may result in adverse health outcomes.
WIC participants must satisfy the eligibility conditions listed in Table 1. The WIC program provides three main benefits to participants: (1) vouchers for specific supplemental foods; (2) nutrition education; and (3) referrals to health care and social service providers. The foods target specific nutrients—protein, vitamins A and C, calcium, and iron. Nutrition education in the WIC program focuses on the relationship between nutrition and health, assists participants to make positive changes in eating habits, and considers ethnic, cultural, and geographic food preferences. WIC providers also advise clients about types of health care, accessible locations of health care, and the utility of health care; however, WIC funds cannot be used directly to provide health care to participants.
Like the FSP, WIC is a food and nutrition assistance program for low-income individuals that attempts to raise the nutrition of participants. However, WIC is expected to be only supplemental to the FSP and is not an entitlement program. Participation in WIC is limited by federal funding levels, which have never been adequate to serve all eligible applicants. Federal regulations specify that a waiting list of eligible applicants be maintained. As program openings become available, a priority system, which gives priority to pregnant and breast-feeding women and infants over children, fills these openings from the waiting list.Program Coverage
Evidence concerning WIC's success in serving eligible individuals indicates almost full coverage (100% participation) of eligible infants but substantially less coverage (57% participation) of eligible children one to four years of age.9 Because WIC is not an entitlement program, estimated coverage rates reflect both the ability of WIC to serve all applicants with available funds and the decision of eligible individuals to apply for and receive WIC benefits. The extremely high infant participation presumably reflects WIC's system of giving priority to infants over children and the strong incentive of receiving free infant formula as an important motivator for eligible mothers.Achievement of Program Goals
Most large-scale evaluation studies of WIC have not used random assignment and, instead, compare the outcomes of WIC participants with those of a comparison group, with adequate statistical controls. The most comprehensive WIC program evaluation was the National WIC Evaluation (NWE), conducted during the early 1980s. The NWE compared outcomes for preschool children enrolled in WIC in 1983 with outcomes for preschool children previously enrolled in WIC and with those for children never enrolled in WIC, with controls for age, sex, and a vast array of socioeconomic characteristics.
Findings from the NWE indicate that participation in the WIC program is associated with increased intakes of some of but not all the nutrients targeted by WIC food packages. WIC participation is associated with higher intakes of iron and vitamin C for both infants and children, lower intakes of calcium and protein for infants, and no significant differences in vitamin A intakes for either infants or children.10 These dietary patterns are consistent with the almost exclusive use of iron-fortified formula by WIC infants compared with the use of whole cow's milk by the comparison group of non- WIC infants.10-12 Whole milk is higher in calcium and protein but lower in iron than WIC formula and is not recommended for infants. The strongest dietary effects were observed for the poorest children and for children from very large families and from female-headed households. Children receiving WIC benefits also were more likely than other similar children to receive any immunizations. Finally, children receiving WIC benefits were significantly more likely to have a regular source of health care than non-WIC children, although no statistically significant relationship was found between WIC participation and the actual use of preventive health care by infants or children.
Overall then, the findings from the NWE suggest that the WIC program achieves some of its program goals, especially regarding the intake of some key nutrients. The NWE may not, however, have adequately controlled for differences in socioeconomic status between WIC children and non-WIC children and may therefore underestimate WIC program effects.
Other evidence from the 1988 National Maternal and Infant Health Survey also indicates improved infant feeding practices for WIC participants. These data show that mothers of infant WIC participants are significantly more likely than mothers of income-eligible nonparticipants to follow infant feeding guidelines and feed iron-fortified formula rather than cow's milk in the fifth and sixth months of infant feeding. 12 It is impossible to determine, however, whether these findings reflect WIC's nutrition education efforts or its provision of iron-fortified formula or a combination of the two. To date, no systematic evaluation of the nutrition education provided by WIC clinics has been conducted, although there are currently some ongoing studies.
In contrast to evaluation studies of the FSP, which focus primarily on food expenditures and dietary outcomes, many studies of the WIC program examine its effects on key health outcomes, in particular, the effects of the food supplements on reducing iron-deficiency anemia and on improving the physical and mental growth and development of infants and children. Although there are few rigorous evaluations of the effects of WIC on anemia, repeated measurements of the hematological status of WIC enrollees provide fairly convincing evidence of WIC's effect on reducing the incidence of iron-deficiency anemia among participating infants.13-16 Mixed and very dated evidence, however, suggests that little is known about the long-term effects of WIC on improving behavioral and cognitive development, outcomes that would presumably result from better iron nutrition status. In addition, little evidence exists concerning the effects of WIC participation on children one to four years of age, an age group that comprises about half of the total WIC caseload.
Other evidence of WIC's beneficial effects comes from studies of pregnancy outcomes among prenatal WIC participants. Numerous studies have documented the effects of prenatal WIC participation on increasing newborn birth weight and preventing low birth weight, preventing preterm delivery, reducing Medicaid costs, and even reducing infant mortality.17-21 While these studies attempt to control for differences in the characteristics of participants and nonparticipants, they generally have not been successful in adequately adjusting estimated effects for potential selection bias. The major problem with these selection bias models is that it is very difficult to find predictors of WIC participation that are not predictors of the outcomes in question, and thus it is very difficult to separate the effects on pregnancy outcomes of prenatal WIC participation from those of other factors. Despite the fact that the research on WIC's beneficial effects on birth outcomes may suffer from selection bias, the number of studies that have examined the effects of prenatal WIC participation, the broad range of outcomes that have been examined, and the efforts to control for participant-nonparticipant differences all suggest some beneficial effects of prenatal WIC participation.Indirect Program Outcomes
WIC is a broad-based program that often goes far beyond providing food in that it attempts to integrate the services available to low-income children. The finding presented earlier that WIC participation is associated with some improvements in immunization status is consistent with both WIC's referral role and with recent evidence that WIC may be used to promote immunizations.22
In addition, WIC may also have had a role in reducing the prevalence of iron-deficiency anemia over time among all infants and children, including those who do not receive WIC. Because WIC vouchers constitute a large share of the market for infant formula and children's cereal, manufacturers may have changed the iron content of their products to meet WIC's eligibility requirements that include iron fortification.