CARDIOVASCULAR DISORDERS                                                           Omar Badawi, Section Advisor

Salt reductions in U.S. diet would save lives and money

Key point: Using the Coronary Heart Disease (CHD) Policy Model, it is projected that reducing salt intake in the American diet by 3 g per day would save almost 90,000 lives and billions of dollars in health care costs each year.

Finer points: Bibbins-Domingo et al. projected the effects of dietary salt restrictions in the United States and their future effects on cardiovascular disease; they published the results in the February issue of the New England Journal of Medicine. Investigators used the CHD Policy Model, a tool that projects changes in the incidence and prevalence of CHD and associated morbidity, mortality, and costs by adjusting for interventions using previously published data. Results indicate that reducing salt in the U.S. diet by 3 g per day would decrease the number of new incidences of CHD by 60,000, stroke by 32,000, and myocardial infarction by 54,000 per year. The number of deaths from any cause would decrease by 44,000 per year. Authors liken the potential benefits of salt restriction to those observed with smoking cessation, weight loss, and a low-cholesterol diet. Projected savings in health care costs are estimated to be $10 billion to $24 billion per year. According to the authors, even a modest reduction in salt intake of 1 g per day achieved gradually over the next 10 years would be more cost effective than using antihypertensive medications. Blacks and older adults tend to be more sensitive to salt; these populations could potentially benefit more than populations that are less sensitive to salt.

What you need to know: Despite years of public health education efforts, Americans appear to be unaware of the amount of salt that they consume daily and of the negative health effects of high salt consumption. Results from previous studies showed that reducing salt in the diet is an inexpensive and effective public health intervention. Currently, the recommended upper limit of salt intake is 5.8 g per day. Most adults should not consume more than 3.7 g of salt daily. The average American man consumes 10.4 g of salt daily, and the average woman consumes 7.3 g of salt daily.

Bibbins-Domingo and colleagues assumed a direct link between high salt consumption and an increased incidence of cardiovascular disease (supported by prospective observational studies), which could limit study results; however, reducing dietary salt likely would have multiple effects. Unintended consequences, such as a compensatory increase in caloric intake, could not have been adjusted for in the analysis.

An accompanying editorial proposed two approaches for reducing Americans’ salt consumption: a public health approach and an individual approach. The former would require food manufacturers to reduce the amount of salt in foods; the latter would require individuals to consume low- or no-salt foods. The public health approach is recommended as the better strategy, as it has been implemented in other countries and appears to be beneficial. Certain manufacturers already offer no-salt processed foods, while others add salt to poultry, meats, and fish, none of which traditionally had added salt. The public health approach was also supported by an analysis in the Annals of Internal Medicine, which showed that collaboration with industry to reduce sodium intake would increase quality-adjusted life-years, reduce strokes and myocardial infarctions, and save billions of dollars in medical costs.

What your patients need to know: Tell patients about the potential negative health effects of high-salt diets. Inform them that the average American consumes more than double the recommended amount of salt per day. Explain to patients that avoiding processed and prepared foods that are high in salt reduces the risk of stroke and heart attack.

Posted by Carli Richard (crichard@aphanet.org)
March 9, 2010