b. individuals as part of natural experiments, such as those in other countries where policies affecting sodium consumption are in effect;
2. effects of low-sodium diets on adverse events among CHF patients receiving therapeutic treatment modalities typically used in the United States; and 3.
3. potential beneficial or adverse outcomes of a range of sodium intakes among African Americans, adults 51-70 years of age, 70 years of age and older, and other population subgroups; RCTs may be particularly important within higher-risk patient populations, where reverse causation is a potential limitation of observational studies.
The committee also identified a need for studies to collect and reanalyze
1. data from existing clinical trials that were designed to evaluate sodium and health; and 2.
2. data during extended follow-up periods after completion of a clinical trial to identify health outcomes, such as mortality, that could manifest later in life and after longer follow-up periods. Such trials would not be simple to conduct, however, and careful feasibility assessment is needed first.
In addition to RCT research, mechanistic studies are needed to examine potential physiologic changes associated with lowering sodium intake and adverse health outcomes. Finally, additional observational research is needed to examine associations between sodium intake and cancer, especially gastric cancer in the U.S. population, as well as associations between sodium intake and caloric intake in both short-term and longitudinal studies.
IOM (Institute of Medicine). 2005. Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. Washington, DC: The National Academies Press.
USDA and HHS (U.S. Department of Agriculture and U.S. Department of Health and Human Services). 2010a. Dietary Guidelines for Americans, 2010. 7th ed. Washington, DC: U.S. Government Printing Office. http://www.cnpp.usda.gov/Publications/DietaryGuidelines/2010/PolicyDoc/PolicyDoc.pdf (accessed February 4, 2013).
USDA and HHS. 2010b. Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010, to the Secretary of Agriculture and the Secretary of Health and Human Services. Washington, DC: USDA/ARS. http://www.cnpp.usda.gov/Publications/DietaryGuidelines/2010/DGAC/Report/2010DGACReport-camera-ready-Jan11-11.pdf (accessed February 1, 2013).