Sodium monitoring key to reducing dietary intakes

U.S. consumers eat and drink too much sodium. Over 90 percent of us consume more than the maximum daily sodium intake recommended by the government, according to national food-intake survey findings reported by the Agricultural Research Service (ARS). Most of our dietary sodium comes from commercially processed and restaurant foods—and reducing sodium in these foods is key to lowering the amount of sodium in the U.S. diet.

Since 2010, researchers at the ARS Nutrient Data Laboratory (NDL) have been collaborating on a project to monitor key sodium-contributing foods with the ARS Food Surveys Research Group, the U.S. Centers for Disease Control and Prevention, and the U.S. Food and Drug Administration (FDA). The two ARS laboratories are part of the Beltsville [Maryland] Human Nutrition Research Center.

The researchers have launched an online, public-access dataset of more than 1,200 foods that contain sodium added during preparation or processing, before purchase by consumers. "The foods we've chosen to monitor serve as indicators for assessing changes in the sodium content of common sodium-contributing commercial foods over time," says NDL nutritionist Jaspreet Ahuja, who heads the project. Foods included in the dataset are ones commonly reported as eaten by respondents in the national food-intake survey called "What We Eat in America."

Of the foods tracked for the project, just over 10 percent (125 items) contribute particularly high levels of dietary sodium and have been termed "sentinel foods."

"Based on the national survey, these sentinel foods account for about one-third of the nation's total adult sodium intake," says Ahuja.

The nutrient content of the foods is periodically assessed by use of objective, nationwide sampling and laboratory analyses to track the progression of important changes over time. Laboratory testing is based on analytical protocols established by the National Food and Nutrient Analysis Program.

All foods in the database were sampled and chemically analyzed between 2010 and 2013 to obtain baseline values. The researchers observed a wide range of sodium levels among foods studied. For example, some canned tomatoes had 4.5 times more sodium than others. Among foods categorized as savory snacks and crackers, plain tortilla chips had one-quarter the sodium of hard pretzels. Most of the foods sampled (88 percent) from fast-food outlets or restaurants exceeded the FDA sodium limit for a claim of "healthy." Consumers and health professionals can use the information to make educated food choices.

The dataset can be found on the ARS website.

The sodium dataset also appears in the annually updated USDA National Nutrient Database for Standard Reference produced by NDL, which itself is imported into multiple computer and online interactive resources, such as the user-friendly ChooseMyPlate.gov.

While the purpose of the dataset is to monitor sodium in foods and in the U.S. diet, other agency professionals and public health officials use the information to focus sodium-reduction efforts. Potassium, total dietary fiber, total and saturated fat, and total sugar are also monitored because their levels may change when manufacturers and restaurants reformulate their products to reduce sodium content.

A detailed report about the collaborative sodium-monitoring program was published in the March 2015 edition of The American Journal of Clinical Nutrition, and a report on sodium content of popular sodium-contributing foods was published in Preventive Medicine Reports in November 2015.