Two-Thirds of Adults Advised to Follow Low-Salt Diet

By John Gever, Senior Editor, MedPage Today Published: March 26, 2009 Reviewed by Zalman S. Agus, MD; Emeritus Professor University of Pennsylvania School of Medicine. ATLANTA, March 26 -- Nearly 70% of adult Americans have risk factors that warrant reducing daily sodium intake to 1,500 mg or less, CDC researchers said.

Based on data from the National Health and Nutrition Examination Survey (NHANES) in 2005 and 2006, CDC's Darwin Labarthe, M.D., Ph.D., and colleagues reported that 145 million adults exhibit one of these three risk factors for sodium sensitivity: they have existing hypertension, they're black, or they're at least 40 years old.

They account for 69.2% (95% CI 67.2% to 71.2%) of all Americans ages 20 and older, the researchers said in the March 27 issue of Morbidity and Mortality Weekly Report.

The most recent recommendations on sodium intake, issued jointly in 2005 by the Department of Health and Human Services and the Department of Agriculture, set a cap of 2,300 mg/day for adults without special risk factors.

People with any of the three risk factors should take no more than 1,500 mg/day, the agencies said.

The main source of sodium in food is salt (sodium chloride [NaCl]). Uniodized salt is 40% sodium by weight. A 1500 mg daily sodium intake therefore represents a daily 3.75 g NaCl intake.

Dr. Labarthe and colleagues found the following prevalence of each risk factor among 1,982 NHANES participants in 2005 to 2006:

• Hypertension: 30.6%
• Age 40 and older without hypertension: 34.4%
• Black, 20 to 39 years old, without hypertension: 4.2%

Hypertension was defined as systolic blood pressure of at least 140 mm Hg, diastolic blood pressure of 90 mm Hg or more, or taking antihypertension medication.