School-age children consume nearly 45% more salt than recommended.

The Centers for Disease Control and Prevention on Sept. 12 issued a study affirming U.S. school-age children, on average, consume levels of sodium well in excess of what is recommended in the Dietary Guidelines for Americans. The study, “Sodium intake among U.S. school-aged children — 2009-10,” suggested strategies that may be employed or accelerated to reduce sodium consumption among young people.

The C.D.C. study pointed to the national health objective of reducing U.S. average sodium intake to below 2,300 mg daily to help prevent high blood pressure, a major cause of heart disease and stroke. The study revealed school-age children on average consume nearly 3,300 mg of sodium per day.

The study was based on a survey of 2,266 children (6-18 years old) participants in “What we eat in America,” the dietary component of the National Health and Nutrition Examination Survey, 2009-10. It broke no new scientific ground with regard to the potential risks of consuming sodium at levels above those recommended in the Dietary Guidelines. It was not meant to do so. Its focus instead was to reveal just how much sodium on average children consume and what are the principal sources of that sodium.

The study indicated about 9 in 10 children eat more sodium than recommenced and that most sodium children consume is in the form of salt as part of processed foods.

It affirmed a high sodium diet may lead to high blood pressure and indicated about one in six children ages 8-17 years has elevated blood pressure.

“Lowering sodium in children’s diets today may help prevent heart disease tomorrow, especially for those who are overweight,” the study asserted.

The study indicated school children’s mean daily sodium consumption was 3,279 mg, and mean sodium density in the food children consumed was 1,638 mg of sodium per 1,000 calories. Total sodium intake was highest among high school age children and among males and was lowest among children who qualified for reduced-price school meals under the National School Lunch and Breakfast Programs. Sodium intake did not vary by race/ethnicity or weight status.

Among children survey participants, 65.1% of sodium consumed came from foods (or ingredients) obtained from a store, 13% from fast food/pizza restaurants, 4.9% from other restaurants, 9.1% from school cafeterias, and 7.4% from other sources.

Among high school age (14-18 years) participants, a higher proportion of total sodium intake came from fast food/pizza restaurants (15.5%) compared with children aged 6-10 years (10.9%) and 11-13 years (10.8%). Among elementary school aged children versus middle and high school age children, a higher proportion of daily sodium came from school cafeteria foods (11.7% versus 8.9% and 7.4%, respectively). Among participants who consumed a school meal on the day of recall for the survey, 26% of sodium came from school cafeteria foods.

The study said children consume about 15% of daily sodium at breakfast, 30% at lunch, 39% at dinner and 16% in snacks.

The study pointed out about 43% of sodium eaten by children comes from just 10 common food types: pizza; bread and rolls; cold cuts and cured meats; sandwiches such as cheeseburgers; snacks, such as chips; cheese; chicken patties, nuggets and tenders; pasta mixed dishes such as spaghetti with sauce; Mexican mixed dishes, such as burritos and tacos, and soup.

Overall, the mean sodium density (1,843 mg/1,000 calories) was highest in fast food/pizza restaurants foods.

Most sodium already is in food before a child buys it or orders it with more than three-quarters of sodium intake derived from commercially processed packaged foods, the study said.

“Results support the need for sodium reduction across multiple foods, venues and eating occasions,” the study asserted. “To reduce U.S. sodium intake, the primary strategy recommended by the Institute of Medicine is reductions in the sodium content of commercially processed and restaurant foods.”

The study said because several commonly consumed foods (e.g., pizza and yeast breads/rolls/buns) are leading contributors to children’s intake of both sodium and energy, strategies to reduce consumption of those sodium-dense foods and/or replace them with lower sodium versions of the same foods, or with potassium rich foods, such as fruits and vegetables, might advance efforts to prevent higher blood pressure and leverage efforts to prevent and reduce childhood obesity.

The higher the sodium density in foods, the less effective caloric reduction could be as a single strategy to reduce sodium intake, the study added.

Another finding from the study pointed to national nutrition standards for school breakfasts and lunches and almost all foods sold in schools that set phased targets for reducing sodium content starting with the 2014-15 school year. The study said evidence suggested that targets are achievable and would result in a 25% to 50% sodium reduction in school meals by 2022.

“Considering sodium from school cafeteria foods contributes about 300 mg daily to overall sodium intake among U.S. school-aged children, and about 870 mg daily on days children consume school meals, this measure could reduce sodium intake by 75 to 150 mg per day overall, and about 220 to 440 mg on days school meals are consumed, if there is no replacement by other sources,” the study said.

According to the study, lowering sodium intake reduces average blood pressure in children, which, if maintained, “could translate into a large reduction in heart attacks and strokes and subsequent mortality. Given the relationship between sodium reduction and high blood pressure, sodium reduction is an important part of the strategy to prevent 1 million heart attacks and strokes by 2017.”

The study had its critics. Lori Roman, president of the Salt Institute, said the latest C.D.C. study and its suggestions were based on a faulty premise.

“The C.D.C. statement is based on the government’s recommendation for sodium intake as contained in the Dietary Guidelines for Americans,” she said. “And these recommendations on sodium have been proven over and over by research to be too low. In fact, they are so low that if anyone ate such a low amount of sodium, they would be at risk of great harm. The government’s recommendations are so low they would put Americans in a danger zone.”

Ms. Roman said scientific research in the past couple of years has suggested a safe zone for sodium consumption between 3,000 and 6,000 mg per day compared with the government’s recommendations of between 1,500 and 2,300 mg. She said the government’s recommended levels were arbitrary and lacked scientific evidence to back them up.