The basic message to consumers about the role of sodium in the development of elevated blood pressure has not changed during the past 40 years, but changes in the target audience as well as the approach to reducing sodium intake have evolved as the science has matured. Many of the early messages and nutrition labeling initiatives focused on persons with diagnosed high blood pressure and those at high risk for high blood pressure or both (Loria et al., 2001), as well as elderly people.
As new science emerged, the focus expanded to include all adults as well as children. The extended focus for adults was based on evidence suggesting that generally reducing sodium intake could prevent or minimize age-related increases in blood pressure. The inclusion of children (2 or more years of age) was based on concerns about the development of preferences for salt taste at young ages and the increasingly earlier development of high blood pressure in adolescents and young adults (DGAC, 2005).
Further, messages for at-risk subgroups within the general population (e.g., persons with hypertension, African Americans, and middle-aged and older persons) continue to be provided because of the higher incidence rates and more serious consequences of excessive sodium intake for these subgroups (DGAC, 2005). These separate messages are based on the understanding that these at-risk subgroups benefit from a more stringent sodium reduction than that recommended for the general population.
Although, as discussed in Chapter 1, the expansion of recommendations to the general population has engendered considerable controversy from some stakeholders (Alderman, 2010; Cohen et al., 2006; Loria et al., 2001; McCarron, 2000, 2008; McCarron et al., 2009), the many expert advisory panels used in the development of sodium reduction recommendations and guidelines, including both those convened by government agencies and those convened independently, have consistently and repeatedly concluded, after careful evaluation of the available scientific evidence and stakeholder concerns, that the scientific evidence warrants extending recommendations for reduction of sodium intake to the general population and across the lifespan.
Over the years, the message content also changed from advice for consumers to reduce the addition of salt added to foods at the table or in home food preparation to choosing high-sodium foods in moderation and using the nutrition label when purchasing foods to enable selection of foods with lower sodium content (Loria et al., 2001). This change was based on evidence showing that the major sources of sodium in the U.S. diet were processed foods and foods obtained from restaurant/foodservice operations rather than from salt added by consumers during home food preparation or at the table.