Report 10 of the Council on Science and Public Health (A-06)

Promotion of Healthy Lifestyles I:  Reducing the Population Burden of Cardiovascular Disease by Reducing Sodium Intake

Summary

Objective:  To review the relationships between dietary sodium intake, blood pressure, and cardiovascular diseases (CVDs), and identify steps needed to reduce the intake of sodium on a population-wide basis.

Methods:  English-language reports were selected from a MEDLINE search of the literature from 1966 to 2006 using the search term hypertension in combination with epidemiology/pathophysiology or *diet therapy or *diet, sodium restricted and *prevention & control.  Additionally, the search term sodium chloride/*adverse effects was used. When identified, meta-analyses were used to provide treatment effects for intervention studies.  Additionally, the Web sites of the National Heart Lung Blood Institute, American Heart Association, U.S. Department of Agriculture, National Academy of Sciences, Food and Drug Administration, and the Salt Institute were searched for relevant information.

Results:  Across populations, the level of blood pressure, the incremental rise in blood pressure with age, and the prevalence of hypertension are related to salt intake. Diets high in sodium, coupled with high rates of CVD worldwide in modern societies, have led to global efforts to reverse this trend.  The majority of sodium intake is derived from amounts added during food processing and preparation.  Various leading scientific organizations and governmental agencies support advice to limit sodium intake to ≤ 2.4 g daily, an amount equivalent to ~6 g of salt.  The virtual absence of either hypertension or of a progressive rise in blood pressure with advancing age in populations with an average sodium intake less than this amount, as well as other epidemiologic evidence, supports the concept of a threshold, above which the risk for harmful CVD consequences begins to increase.  Results of the Dietary Approaches to Stop Hypertension (DASH)-Sodium Trial showed that the most substantial benefit in reducing systolic blood pressure was gained from reducing sodium intake from 2.3 g to 1.5 g per day.  Attaining this lower level of intake on a population basis would require that sodium in processed and restaurant foods be lowered an average of ~80% (assuming that 75% to 80% of the daily sodium intake continues to be derived from such foods).

Conclusion:  The public health advice to reduce sodium intake is intended to influence (downward) the overall distribution of sodium intakes and, thereby, the incidence of hypertension in the population.  With an appropriate food industry response, combined with consumer education and knowledgeable use of food labels, the average consumer should be able to choose a lower sodium diet without an inordinate level of dietary restriction, inconvenience, or loss of food enjoyment.  In the continued absence of voluntary measures adopted by the food industry, new regulations may be required to achieve lower sodium concentrations in processed and prepared foods.  Blood pressure also is affected by other foods and nutrients, and a reduced salt intake should be only one component of a comprehensive strategy to lower blood pressure.  Increasing physical activity, consuming a diet high in fruits and vegetables and low in saturated and total fat, and moderation in alcohol intake are also recommended lifestyle approaches to preventing and managing hypertension, and reducing its impact on CVD.

RECOMMENDATIONS

The following statements, recommended by the Council on Science and Public Health, were adopted by the AMA House of Delegates as AMA directives at the 2006 AMA Annual Meeting:

1. The AMA calls for a stepwise, minimum 50% reduction in sodium in processed foods, fast food products, and restaurant meals to be achieved over the next decade.  Food manufacturers and restaurants should review their product lines and reduce sodium levels to the greatest extent possible (without increasing levels of other unhealthy ingredients).  Gradual but steady reductions over several years may be the most effective way to minimize sodium levels.  (Directive)
2. The AMA urges the Food and Drug Administration (FDA) to revoke the “generally recognized as safe” (GRAS) status of salt, and to develop regulatory measures to limit sodium in processed and restaurant foods.  (Directive)
3. To assist in achieving the Healthy People 2010 goal for sodium consumption, the AMA will work with the FDA, the National Heart Lung Blood Institute, the Centers for Disease Control and Prevention, the American Heart Association, and other interested partners to educate consumers about the benefits of long-term, moderate reductions in sodium intake. (Directive)
4. The AMA will discuss with the FDA ways to improve labeling to assist consumers in understanding the amount of sodium contained in processed food products, and to develop label markings and warnings for foods high in sodium. (Directive)
5. The  AMA recommends that the FDA consider all options to promote reductions in the sodium content of processed foods. (Directive)

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NOTE:  A revised version of this report has been published:  Dickinson BD, Havas S, for the Council on Science and Public Health. Reducing the population burden of cardiovascular disease by reducing sodium intake.  Arch Intern Med. 2007;167(14):1460-1468. (Available online to AMA members only.)

Also see the AMA's  Promoting healthy lifestyles Web site.