UC Davis USDA Economic Research Service RIDGE Program

Investigator: Janet Wojcicki, MD, MPH
Sponsor: University of California Davis

Location(s): United States


Uniform nutrition labels were introduced as part of the Nutrition Labeling and Education Act (NLEA) in 1994. Use of food labels has been associated with increased knowledge about the nutrition and fat content of food and a reduction in fat intake. Similarly, knowledge of the dietary guidelines is associated with increased likelihood of meeting dietary guidelines for fruit, dairy, and protein. However, little is known about the frequency of nutrition label reading or awareness of dietary guidelines or other nutritional programs by at-risk populations, such as participants in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) or adolescents who are beginning to make food purchases for themselves.

The 2005-06 National Health and Nutrition Examination Survey (NHANES) added new questions to evaluate awareness of dietary guidelines and other nutrition programs, as well as questions on the use of nutrition facts panels and ingredient lists. This study used NHANES data to investigate the relationship between responses (n=643 for 2005-06) to the nutritional and diet questions from (1) mothers of children ages 0-5, comparing WIC participants with WIC-eligible nonparticipants, and (2) adolescents ages 16-19 (n=1,160). Specifically, the study assessed nutritional awareness of programs such as “Dietary Guidelines for America,” “Food Guide Pyramid,” and “5-A-Day for Better Health Program.” The study further analyzed nutritional behavior based on the frequency of participants’ use of the nutrition facts panel, list of ingredients, size of a serving, and information on total calories, product calories from fat, total fat content, trans fat content, saturated fat, cholesterol, and sodium in making a product selection.

The main outcomes of interest included maternal and adolescent nutritional awareness of nutritional program and active use of nutritional panel information. Statistical analyses included chi-square tests to evaluate differences in proportions and t-tests to evaluate differences in means. Multivariate logistic regression models were used to assess binary outcomes for awareness of nutritional programs and frequency of use of nutrition label programs while adjusting for maternal age, education level, and race/ethnicity. For adolescents, nutritional awareness and use of nutritional information was also evaluated in relationship to overweight and obesity.

Less than 25 percent of adolescents regularly check the nutritional information on the facts panel prior to making a food purchase, with 23.7 percent checking the calories from fat and total calories and 16.4 percent checking the trans fats. Only 25.1 percent said that they regularly evaluated the ingredient list on a food label prior to making a food purchase, while 43.8 percent stated that they used the health claims on a food package to influence their food purchases. A much higher percentage of adolescents was aware of the Food Pyramid guidelines (92.4 percent), while only 29.3 percent had heard of the Dietary Guidelines and 43.5 percent had heard of the 5-A-Day for Better Health Program. Adolescent overweight and obesity was not associated with the frequency of use of the nutritional facts panel information or nutritional awareness of most programs. Adolescents of normal weight, however, had greater odds of having heard about the 5-A-Day Program (odds ratio (OR) 1.23, 95-percent confidence interval (CI) 1.00-1.52) compared with overweight/obese adolescents but were less likely to check cholesterol on food labels (OR 0.53, 95-percent CI 0.28-1.00).

The study found a consistently lower frequency of awareness of nutritional programs among WIC participants than among WIC-eligible nonparticipants and a more infrequent use of the nutrition facts panel information. Specifically, 35.7 percent of WIC participants had heard of the dietary guidelines, whereas 45.1 percent of eligible nonparticipants were aware of this program. For the Food Pyramid, 76.9 percent of WIC participants were aware of this program compared with 85.3 percent of eligible nonparticipants. For the 5-A-Day Program, 44.4 percent of WIC participants knew of this program compared with 52.1 percent of nonparticipants. Only 19.1 percent of WIC participants stated that they used the nutritional facts panel information prior to making a food purchase compared with 31.1 percent of nonparticipants.

The differences were also significant for checking the food label for calories (54.6 percent of WIC participants versus 81.1 percent of nonparticipants), total fat (52.5 percent versus 72.8 percent), and trans fats (30.6 percent versus 60.5 percent). When we adjusted for maternal age, ethnicity, and education level, we found that WIC participants had decreased odds of using the facts panel to check calories (OR 0.26, 95-percent CI 0.14-0.49), trans fats (OR 0.25, 95-percent CI 0.10-0.62), or saturated fats (OR 0.35, 95-percent CI 0.14-0.88) compared with eligible nonparticipants. WIC participants were also less likely to use the ingredient list compared with eligible nonparticipants (OR 0.45, 95-percent CI 0.22-.96). When we adjusted for potential confounders in multivariate logistic regression analysis, we found no difference between WIC participants and nonparticipants in terms of differences in awareness of nutritional programs.

In summary, the study found a low frequency of using nutritional facts panel information (less than 30 percent) by adolescents in the United States. Awareness of nutritional programs by adolescents varied with greater recognition of the Food Pyramid Program than of the 5-A-Day Program or the Dietary Guidelines. When we adjusted for age, education level, and race/ethnicity, we found that WIC participation among mothers with children younger than 5 years and pregnant women was associated with less frequent use of the nutrition facts panel information.