UNC Study: Improvements in WIC packaging led to overall food choice improvements

An improvement in the food choices and nutritional content of WIC (Special Supplemental Nutrition Program for Women, Infants and Children), packages has produced analogous changes in overall food purchase habits among program participants.

Dr. Shu Wen Ng

Dr. Shu Wen Ng

Those are the findings in a new study from the University of North Carolina’s Gillings School of Global Public Health. The study, which profiled 4,537 low-income households with preschool-aged children—all of which were income eligible for WIC, but only a subset participated in the program—found that those households that did participate in WIC and received the improved food packages were subsequently buying fewer calorie-dense, pre-packaged foods with high amounts of sugar and salt. The pre-packaged foods purchased by WIC-eligible households that did not participate in the program had similar, but less-pronounced reductions.

The study, titled “Federal Nutrition Program Revisions Impact Low-income Households’ Food Purchases,” was published online on Feb. 14, 2018 in the American Journal of Preventive Medicine and led by Shu Wen Ng, PhD, associate professor of nutrition at UNC’s Gillings School of Global Public Health. According to Ng, the findings showed that after major revisions to the WIC packages that begun in 2009, WIC-participating households had improved nutritional profiles in their overall food purchases, beyond their food purchases that were part of the WIC packages.

“We found that the WIC food package revisions directly correlated with improved nutritional profiles of food purchases among WIC-participating households,” Ng said. “One of the most striking and encouraging results was that these improvements became more pronounced over time.”

Among the findings were that, as they became familiar with the more nutritional WIC-subsidized food, participating households purchased WIC and non-WIC-subsidized food containing significantly fewer calories, sodium, fat and sugar from pre-revision periods. This included declines of more than nine percent and 30 percent, respectively, of the recommended daily sodium and sugar intake for adults, and nine and 60 percent declines for pre-school-aged children.

WIC food packages are an income-eligible program created for pregnant and lactating mothers and children under 5 living at or below 185 percent of the U.S. Poverty Income Guidelines and based on participant age and developmental status. The packages have traditionally included milk, eggs, cereals, whole grains, legumes and juice. The foods available in the packages had remained relatively unchanged from the program’s inception in 1972 until a decision was made to implement revisions in 2009. The revisions were based on the 2005 Dietary Guidelines for Americans and the American Academy of Pediatrics infant feeding guides. The revisions included such foods as whole-grain breads and cereals, as well as fruits and vegetables, all of which were available with WIC vouchers.

Ng’s team tracked purchases of foods in 4,537 low-income, WIC-eligible households, excluding non-packaged foods, using the Nielson Homescan Panel. Analysis was based on such nutrients as calories, sugar, fats, sodium, protein and fiber purchased each quarter.

“Because we looked at overall household purchases, that is, not just WIC-subsidized purchases, our results suggest that the WIC package revisions and associated efforts may be helping WIC families make healthier choices among their overall packaged food purchases,” Ng said.

Ng adds that, as the WIC program considers further revisions based on the Jan. 2017 report by the National Academies of Sciences, Engineering and Medicine, continued evaluation of WIC household purchases will be useful to determine effects of further modifications.

The paper was co-authored by Gillings School research assistants Bridget A. Hollingsworth, MPH, RD; Emily A. Busey, MPH, RD; Julie L. Wandell, MPH, RD; as well as Donna R. Miles, PhD, programmer on the Ng team, and Jennifer M. Poti, PhD, research assistant professor of nutrition.

Funding for this study comes from the Robert Wood Johnson Foundation via its Healthy Eating Research Program and the National Institutes of Health via the Carolina Population Center.