Study indicates nutritional benefits of the WIC program

February 06, 2004

CHAPEL HILL — A University of North Carolina at Chapel Hill-led research team has found that preschoolers enrolled in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) show positive nutritional behaviors and intakes beyond the program’s goals.The new study is published in this month’s issue of the Journal of Pediatrics.The WIC Program was implemented in 1974 to improve the diets of low-income women and children by providing vouchers to purchase specific foods each month. Previous studies have determined that WIC participants show an increase in levels of vitamins A, B6 and C, protein and iron – nutrients specifically targeted by the program.

WIC is a critical national public health program for improving the nutritional status of a very vulnerable population, said Dr. Anna Maria Siega-Riz, associate professor of nutrition and of maternal and child health in UNC’s School of Public Health. Siega-Riz, formerly a WIC director in Davidson County (N.C.), led the research team. She also is a fellow with the Carolina Population Center.

“With an increase in funding in the late 1990s, more children have been served than ever before. It is, therefore, not surprising that the benefits of the program – which include nutrition education – have made an impact on preschoolers’ intake and behaviors,” she added.

Using a nationally representative sample of the U.S. population from 1994-98, collected by the U.S. Department of Agriculture, the research team evaluated fat, fruit, vegetable and added sugar intake, as well as snacking behavior among WIC participants. The researchers determined the overall prevalence of snacking among preschoolers enrolled in WIC, a behavior linked to obesity, to be significantly lower than that of non-participants.

In addition, WIC participants whose family incomes were less than 130 percent of poverty (the cutoff used for the Food Stamp Program) experienced a beneficial effect on the intake of fat, carbohydrates, added sugar and fruit. Their diets were higher in the percentage of energy from carbohydrates and in the number of serving of fruits, and lower in the percentage of energy coming from fats and in the amount of added sugars.

Benefits among study participants with higher incomes – up to 185 percent of poverty – were limited to lower added sugar intakes and higher iron and fruit intakes. In both income groups, nutrient intake due to snacking showed a beneficial effect only on added sugar intake and suggested the same for iron and fruit intake.

Primary caretakers, the mother in most cases, reported on the child’s diet, and each eating occasion was self-identified. Added sugar intake includes sugars containing ingredients added during food processing or preparation, candy and sugar added at the table.

“The nutritional problems that face our country today, such as obesity and chronic diseases, are slightly different from those that existed in the late ’60s and early ’70s, such as inadequate protein and energy intakes associated with malnutrition,” said Siega-Riz.

“It’s important to evaluate if the program, which has changed little in terms of the foods that are offered, continues to make an impact in the population that it serves. Also important is to keep in mind that the nutrition education provided along with the vouchers has changed over time and, thus, is likely to have contributed to the benefits that we are seeing.”

The data set used did not allow for a direct analysis of that sort, she added.

This analysis demonstrates the continued importance of public food assistance and nutrition programs among low-income women and children, said Siega-Riz. With the present increase in fat consumption, eating out and snacking among all American income levels, WIC is potentially beneficial to change diet behaviors not specifically targeted by the program, she added.

Because nutritional snacks also may have a positive impact on children’s diets, providing access to more fruits and vegetables through the WIC program may be another way to improve participants’ overall health, said Siega-Riz.

Other members of the research team are Dr. Sibylle Kranz, an assistant professor in the department of nutritional sciences at Pennsylvania State University; Dan Blanchette, an analyst at the Carolina Population Center; Dr. David K. Guilkey, a professor of economics in UNC’s College of Arts and Sciences; and Dr. Pamela S. Haines, associate professor, and Dr. Barry M. Popkin, professor, both of UNC’s nutrition department.

The research was funded by a cooperative agreement with the U.S. Department of Agriculture.

The Journal of Pediatrics is a primary reference for the science and practice of pediatrics and its subspecialties.

Note: Siega-Riz can be reached at (919) 962-8410 or

School of Public Health contact: Lisa Katz, (919) 966-7467 or

Journal of Pediatrics contact: Terri Stridsberg, (513) 636-7140 or