Potato chips, frozen pizza, a fast food hamburger-these foods are popular in the American diet and saturated with sodium. Though eating too much can lead to high blood pressure and heart disease, 90 percent of Americans eat more than the recommended amount of sodium per day.
The need to reduce sodium consumption is clear, but new research from the University of Georgia has determined that one popular approach-nutrition labeling-doesn't work.
"Currently we don't know which interventions are most effective to reduce sodium intake in the U.S. population, and the Nutrition Labeling and Education Act is the only policy in the U.S. focusing on informing consumers about sodium content on most packaged foods," said Donglan "Stacy" Zhang, assistant professor of health policy and management at UGA's College of Public Health and lead author on the study.
Nutrition labels are designed to help consumers make the best food choices for their health, which is why calories, fats and other major nutrients like protein, fiber, and vitamins and minerals are prominently featured.
In a recently published paper in the American Journal of Preventive Medicine, Zhang and her co-authors examined the link between regularly reading nutrition labels and consumption of high-sodium foods.
Using two consumer behavior datasets from the National Health and Nutrition Examination Survey, the researchers compared how frequently participants used nutrition labels and their daily sodium intake.
They found a small effect. Frequent nutrition label users consumed 92 milligrams less sodium per day than infrequent nutrition label users, but label readers were still eating around 3,300 milligrams of sodium, well over the Food and Drug Administration's recommended upper limit of 2,300 milligrams per day.
"That's a very small reduction," said Zhang. "Without health promotion, without any other additional education intervention, nutrition labeling has little impact on sodium consumption."
Zhang points to the need for better label design. The current label can present challenges to some consumers with limited education or non-English speakers. Visual or color-coded designs, like the traffic light model used on food packaging in the U.K., can overcome low literacy.
"We need more research in this area, how to better design the label and how to best get this information to consumers to guide their decision-making," she said.
Zhang also found that the effect varied widely across age, gender and socioeconomic groups. Specifically, low income consumers were less likely to use nutrition labels.
"We suspect that low-income people are more concerned about other variables such as food prices or convenience," she said. "Those other competing variables may be more important to them than nutrition values in their food products."
Interventions that increase nutritious food choices for low-income consumers, she says, may be a more successful way to reduce sodium intake in these groups.
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Donglan Zhang et al. Nutrition Label Use and Sodium Intake in the U.S., American Journal of Preventive Medicine (2017). DOI: 10.1016/j.amepre.2017.06.007