Patient understanding of food labels: the role of literacy and numeracy.

BACKGROUND: Comprehension of food labels can be important for patients, including those with chronic illness, to help follow dietary recommendations. Patient comprehension of food labels was examined, along with the relationship of comprehension to their underlying literacy and numeracy skills.
METHODS: From June 2004 to April 2005, a cross-sectional study of 200 primary care patients was performed. A 24-item measure of food label comprehension was administered. Literacy was measured with the Rapid Estimate of Adult Literacy in Medicine (REALM), and numeracy with the Wide Range Achievement Test, third edition (WRAT-3).
RESULTS: Most patients (89%) reported using food labels. While 75% of patients reported at least a high school education and 77% had 9th-grade literacy skills, only 37% had 9th-grade math skills. On average, patients answered 69% (standard deviation, 21%) of the food-label questions correctly. Common reasons for incorrect responses included misapplication of the serving size, confusion due to extraneous material on the food label, and incorrect calculations. For example, only 37% of patients could calculate the number of carbohydrates consumed from a 20-ounce bottle of soda that contained 2.5 servings. Higher comprehension of food labels was significantly correlated (all p values were less than 0.001) with higher income (rho=0.39), education (rho=0.49), literacy (rho=0.52), and numeracy (rho=0.67).
CONCLUSIONS: Patients demonstrated deficits in understanding nutrition labels. Poor label comprehension was highly correlated with low-level literacy and numeracy skills, but even patients with higher literacy could have difficulties interpreting labels. Providers need to consider patients' literacy and numeracy when providing dietary recommendations. Opportunities may exist for the U.S. Food and Drug Administration to promote changes to make food labels more comprehensible.