Washington: Scientists have found that on any given day 49 per cent of US adults eat at least one sandwich, and sandwiches account for one-fifth of their total daily sodium intake.
Researchers analysed data from a dietary intake survey known as "What We Eat in America NHANES 2009-2010," conducted in the US.
In What We Eat in America NHANES 2009-2010, participants reported everything they ate and drank the previous day. Each food and beverage reported was then assigned one or more food codes so that its nutrient content could be determined.
For most sandwiches, participants reported the various components of their sandwich (such as bread and fillings) individually. Those components were then coded separately with multiple food codes that were linked to indicate they were eaten together as a sandwich.
Because previous studies had defined sandwiches as only those that were represented by a single food code, those analyses found that sandwiches only contributed about 4 per cent of daily sodium intake.
In the new study, a team of US Department of Agriculture (USDA) researchers broadened the sandwich definition by including sandwiches that were coded as multiple ingredients as well as those coded using a single food code.
By including sandwiches coded both ways, researchers discovered that sandwiches actually account for one-fifth of total sodium intake and that on any given day nearly half of the adults in America aged 20 years and older eat a sandwich.
The 2010 Dietary Guidelines for Americans recommend a maximum intake of 2,300 milligrammes of sodium per day.
For certain groups - adults over 50, African-Americans, and those with certain medical conditions, such as high blood pressure, diabetes, or chronic kidney disease - the recommended amount is reduced to 1,500 milligrammes per day.
The study found that, for adults, sandwiches alone contribute 30 per cent of the less restrictive guideline and 46 per cent of the stricter guideline.
Researchers also found that people who ate sandwiches had significantly higher energy intakes than those who did not.
Those who consumed a sandwich on the survey day took in, on average, around 300 kilocalories more than those who did not report eating a sandwich.
Those who ate a sandwich also had higher total sodium intakes, averaging around 600 milligrammes per day higher than those who did not consume a sandwich.