On any given day, nearly half of American adults eat at least one sandwich, which accounts for one-fifth of the recommended daily sodium intake, reveals a study published in the Journal of the Academy of Nutrition and Dietetics.

The 2010 Dietary Guidelines for Americans is 2,300 mg of sodium for most Americans. For people over age 50, as well as African-Americans, and people with high blood pressure, chronic kidney disease or diabetes, it’s 1,500 mg of sodium per day. Excessive sodium consumption can result in high blood pressure, a cause of heart disease and stroke— two leading causes of death in the United States, according to the Centers for Disease Control and Prevention (CDC).

Depending on the person, sandwiches can contribute 30 to 46 percent of daily sodium intake recommendations.

In the study, about 5,760 adults over age 20 recorded what they ate and drank the previous day, Medical News Today reported. Participants listed exactly what was on each of their sandwiches, and researchers assigned each food and beverage one or more food codes to assess their nutritional content.

Previous studies didn’t take specific ingredients into account, but rather considered sandwiches based on a single code. Based on those studies, scientists believed that sandwiches were responsible for only 4 percent of daily sodium intake.

Some of the sandwiches in this study were still given a single code, specifically fast food items— such as a turkey submarine sandwich with cheese, lettuce, tomato and spread.

"In 2009-2010, only about 20 percent of all sandwiches were represented by a single food code," said study co-author Rhonda Sebastian, a U.S. Department of Agriculture (USDA) Research Service (ARS) nutritionist. "For that reason, previously published estimates of sandwich contributions to sodium intake that were based on only single-code sandwiches are considerably underestimated."

Researchers from the USDA and investigators at the Food Surveys Research group also found that those who ate a sandwich also consumed about 300 more calories than those who did not, Medical News Today reported.

Those who reported having a sandwich also ended up consuming around 600 mg more sodium per day than those who didn’t.

Study co-author and ARS nutritionist Cecilia Wilkinson Enns said these findings don’t suggest that sandwiches should be out-ruled as a lunch choice, but that consumers should consider ingredient choices when opting for the fare.

"The unanticipated finding that sandwich consumption is associated with higher overall intake of energy underscores the importance of making healthful choices of sandwich ingredients,” Enns said. “Many sandwiches, such as burgers and franks, and common sandwich components, such as yeast breads, cheese and cured meats, are among the top contributors not only to sodium but also to energy in the diets of adult Americans."

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