Hold the Salt

Overconsumption of sodium is a persistent problem in the United States. It leads to high blood pressure and contributes to related illnesses, such as cardiovascular disease. The Institute of Medicine (IOM) recommends that adults consume no more than 2,300 milligrams (mg) of sodium each day, with lower amounts recommended for groups at higher risk of developing high blood pressure. It seems intuitively clear that reducing sodium intake would improve Americans' health and reduce medical costs; yet, to date, the potential benefits have not been quantified. To address this gap, RAND researchers used a simulation model to estimate the effects of reducing average sodium consumption, across the adult U.S. population, on

1. the prevalence of hypertension
2. the direct medical costs of treating high blood pressure
3. quality of life.

The model incorporated information about adult Americans' blood pressure levels, use of antihypertensive medications, and sodium intake from the National Health and Nutrition Examination Survey, a federal study that assesses Americans' health and nutritional status. Results showed the following:

• Reduced prevalence of high blood pressure. The study estimated that the average American adult consumes 3,400 mg of sodium per day and that 70 percent of adults consume more than the recommended amount. Reducing average consumption to meet IOM's national sodium guidelines could eliminate at least 11 million cases of high blood pressure nationally, which could extend the lives of thousands of people each year.
• Lower direct medical costs. The lower prevalence of high blood pressure would translate into approximately $18 billion per year in direct health care cost savings. About half of the savings are likely to accrue to the public sector.
• Improved quality of life. Meeting sodium consumption guidelines would save, in one year, 312,000 quality-adjusted life years—a metric that accounts for increased longevity as well as the relative healthiness experienced during additional years of life. The annual monetary value of this improvement would be an estimated $32 billion.

The researchers note that these estimates are conservative because they exclude several sources of potential savings: health benefits experienced by people who start with low blood pressure or who retain high blood pressure even after lowering their sodium intake, the benefits of reducing the ill effects of cardiovascular disease outside of the hypertension link, and the benefits of reducing future illness by lowering current blood pressure levels.

Lowering sodium intake across the nation's population will not be easy. Studies suggest that more than 75 percent of Americans' dietary sodium intake comes from processed foods, rather than from salt added during cooking at home or at the dining table. Restaurant food also is generally high in sodium. Strategies that are currently being considered by policymakers include redesigning food labels to highlight sodium levels, having manufacturers voluntarily lower sodium levels, and adopting regulations that would require food processors to lower sodium.