A substantial body of clinical research has examined the relationship between higher-than-recommended sodium intake and blood pressure as well as other health outcomes. Study designs and approaches including animal studies,1–3 human genetic studies,4,5 observational epidemiologic studies,6–14 controlled interventions,15–24 and meta-analyses25–27 provide evidence that excessive sodium intake increases blood pressure in human populations. There is also evidence from research studies showing that sodium reduction might reduce the risk of gastric cancer, end-stage kidney disease, left ventricular hypertrophy, congestive heart failure, and osteoporosis.28
Worldwide, high blood pressure is a leading cause of preventable morbidity and mortality.29 Given the relationship of high blood pressure to increased risk of heart disease, stroke, congestive heart failure, and kidney disease, excessive sodium intake is a serious public health problem that is amenable to intervention. Despite campaigns that often target individuals to encourage lower sodium intake, consumption is far in excess of recommendations. In the United States, dietary sodium intake averages approximately 3400 mg/d, although less than 2300 mg/d is recommended by the Dietary Guidelines for Americans for the general population.30 For certain population subgroups, the Dietary Guidelines for Americans recommends 1500 mg/d. Furthermore, adherence to recommended levels of sodium intake is extremely low in the United States, and most age groups including children have an average sodium intake that is much higher than recommended.31 In fact, less than 10% meet the recommendation for less than 2300 mg/d and less than 2% meet the recommendation for less than 1500 mg/d.32 Difficulties in adherence are likely due to the fact that the most common dietary sources of sodium are commercially processed foods.33,34
Proposed strategies for sodium reduction include reducing sodium in the food supply and motivating consumers to express a desire for easy access to healthful foods, enabling them to meet the recommendations of the Dietary Guidelines for Americans.35 There is also increasing recognition of the importance of the food environment in shaping dietary behavior and the need for strategies that focus on changing community-level environmental factors that support a shift in behavior toward more healthful eating. Data suggest that neighborhood availability of healthful foods influences eating patterns.36
The success of sodium-reduction strategies hinges on finding successful approaches to engage multiple stakeholders, especially communities, in innovative and effective strategies that will be sustainable. Several articles in this supplement describe environment-level changes (eg, encouraging scratch cooking and changing policies on procurement sources) in a variety of settings (eg, schools, restaurants, and community meal programs) for a variety of populations (eg, children, adults, and the elderly). These articles demonstrate that community-based programs have the potential to change food environments, hopefully ensuring improved ability to meet guidelines. The authors discuss the importance of motivating individuals to care about sodium intake, educating food service staff, communicating with consumers to create a demand for healthful foods, and providing them with skills and tools to reduce their sodium intake when desired.
There is a need for further collective action to replicate successful strategies and to develop and implement additional approaches. Existing voluntary sodium-reduction initiatives in some US communities are admirable and should be replicated so that all communities can meet dietary guidelines. In addition, several countries including the United Kingdom, Finland, and Ireland have implemented aggressive public health programs to reduce salt intake. In the United States, a positive step is that several food manufacturers, through the National Salt Reduction Initiative, are reformulating products and have pledged to gradually reduce the sodium content of key foods in coming years. Furthermore, to the extent possible, data should be generated to provide evidence to support these approaches.
Reducing sodium intake and the resultant changes in cardiovascular health in the population also mean focusing greater attention on those who are at greatest risk. Studies show that a higher percentage of individuals from racial/ethnic minority groups and individuals with lower socioeconomic status have limited access to healthy foods.37 These populations also have higher rates of cardiovascular diseases and risk factors for cardiovascular diseases.38,39 Special efforts should be made to ensure that community-level sodium-reduction efforts reach all populations, especially those at highest risk.
Practice-based evidence such as the projects described in this issue of the Journal, coupled with evidence from well-conducted clinical studies of sodium and health, will continue to build the foundation for public health interventions that achieve and sustain sodium reduction in the general population. Let's move beyond the clinic and engage our communities in this important public health effort.
1. Denton D, Weisinger R, Mundy NI, et al. The effect of increased salt intake on blood pressure of chimpanzees. Nat Med. 1995;1:1009–1016.
2. Elliott P, Walker LL, Little MP, et al. Change in salt intake affects blood pressure of chimpanzees: implications for human populations. Circulation. 2007;116:1563–1568.
3. Meneely GR, Ball OT. Experimental epidemiology of chronic sodium chloride toxicity and the protective effect of potassium chloride. Am J Med. 1958;25(5):713–725.
4. Lifton RP. Molecular genetics of human blood pressure variation. Science. 1996;272:676–680.
5. Lifton RP, Gharavi AG, Geller DS. Molecular mechanisms of human hypertension. Cell. 2001;104:545–556.
6. Uzodike VO. Epidemiological Studies of Arterial Blood Pressure and Hypertension in Relation to Electrolyte Excretion in Three Igbo Communities in Nigeria [MD thesis]. London, England: University of London; 1993.
7. Page LB, Damon A, Moellering RC Jr. Antecedents of cardiovascular disease in six Solomon Islands societies. Circulation. 1974;49:1132–1146.
8. Page LB, Vandevert DE, Nader K, Lubin NK, Page JR. Blood pressure of Qash'qai pastoral nomads in Iran in relation to culture, diet, and body form. Am J Clin Nutr. 1981;34:527–538.
9. Kesteloot H, Huang DX, Li YL, Geboers J, Joossens JV. The relationship between cations and blood pressure in the People's Republic of China. Hypertension. 1987;9:654–659.
10. Sasaki N. High blood pressure and the salt intake of the Japanese. Jpn Heart J. 1962;3:313–324.
11. He J, Klag MJ, Whelton PK, et al. Migration, blood pressure pattern, and hypertension: the Yi Migrant Study. Am J Epidemiol. 1991;134(10):1085–1101.
12. Poulter NR, Khaw KT, Hopwood BEC, et al. The Kenyan Luo migration study: observations on the initiation of a rise in blood pressure. BMJ. 1990;300(6730):967–972.
13. Dahl LK. Possible role of salt intake in the development of essential hypertension. In: Cottier P, Bock D, eds. Essential Hypertension—An International Symposium. Berlin, Germany: Springer-Verlag; 1960:52–65.
14. Stamler J. The INTERSALT study: background, methods, findings, and implications. Am J Clin Nutr. 1997;65:626S–642S.
15. Luft FC, Rankin LI, Bloch R, et al. Cardiovascular and humoral responses to extremes of sodium intake in normal white and black men. Circulation. 1979;60:697–703.
16. Weinberger MH. Salt sensitivity of blood pressure in humans. Hypertension. 1996;27:II481–II490.
17. Weinberger MH. Salt sensitivity, pulse pressure and death in normal and hypertensive humans. Hypertension. 2001;37(pt 2):429–432.
18. Laatikainen T, Pietinen P, Valsta L, et al. Sodium in the Finnish diet—20-year trends in urinary sodium excretion among the adult population. Eur J Clin Nutr. 2006;60:965–970.
20. Appel LJ, Moore TJ, Obarzanek E, et al.; for the DASH Collaborative Research Group. A clinical trial of the effects of dietary patterns on blood pressure. N Engl J Med. 1997;336:1117–1124.
21. Sacks FM, Svetkey LP, Vollmer EM, et al.; for the DASH-Sodium Collaborative Research Group. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. N Engl J Med. 2001;344:3–10.
22. Whelton PK; on behalf of the Trials of Hypertension Prevention Collaborative Research Group. The effects of nonpharmacologic interventions on blood pressure of persons with high normal levels. JAMA. 1992;267(9):1213–1220.
23. Whelton PK, Lawrence LJ, Espeland M, et al. Sodium reduction and weight loss in the treatment of hypertension in older persons. JAMA. 1998;279(11):839–846.
24. Cook NR, Cutler JA, Obarzanek E, et al. Long term effects of dietary sodium reduction on cardiovascular disease outcomes: observational follow-up of the trials of hypertension prevention (TOHP). BMJ. 2007;334:885–888.
25. Midgley JP, Matthew AG, Greenwood CM, Logan AG. Effect of reduced dietary sodium on blood pressure: a meta-analysis of randomized controlled trials. JAMA. 1996;275:1590–1597.
26. He FJ, MacGregor GA. Effect of modest salt reduction on blood pressure: a meta-analysis of randomized trials. Implications for public health. J Hum Hypertens. 2002;16:761–770.
27. Hooper L, Batlett C, Smith GD, Ebrahim S. Systematic review of long term effects of advice to reduce dietary salt in adults. BMJ. 2002;325:628–634.
28. Institute of Medicine. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements (Sodium and Potassium). Washington, DC: National Academies Press; 2006.
29. Lawes CM, Vander Hoorn S, Rogers A; International Society of Hypertension. Global burden of blood-pressure-related disease, 2001. Lancet. 2008;371:1513–1518.
30. US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans. Washington, DC: US Department of Health and Human Services.
32. Cogswell ME, Zhang Z, Carriquiry AL, et al. Sodium and potassium intakes among US adults. NHANES 2003-2008. Am J Clin Nutr. 2012;96(3):647–657.
33. Mattes RD, Donnelly D. Relative contributions of dietary sodium sources. J Am Coll Nutr. 1991;10:383–393.
34. Anderson CA, Appel LJ, Okuda N, et al. Dietary sources of sodium in China, Japan, the United Kingdom, and the United States, women and men aged 40 to 59 years: the INTERMAP study. J Am Diet Assoc. 2010;110:736–745.
35. Institute of Medicine. Strategies to Reduce Sodium Intake in the United States. Washington, DC: The National Academies Press; 2010.
36. Franco M, Diez Roux AV, Glass TA, Caballero B, Brancati FL. Neighborhood characteristics and availability of healthy foods in Baltimore. Am J Prev Med. 2008;35(6):561–567.
37. Wang Y, Chan X. How much of racial/ethnic disparities in dietary intakes, exercise, and weight status can be explained by nutrition—and health-related psychosocial factors and socioeconomic status among US adults? J Am Diet Assoc. 2011;111(12):1904–1911.
38. Mensah GA, Mokdad AH, Ford ES, Greenlund KJ, Croft JB. State of disparities in cardiovascular health in the United States. Circulation. 2005;111(10):1233–1241.
39. Stamler J, Elliott P, Appel LJ, et al. Higher blood pressure in middle-aged American adults with less education—role of multiple risk factors: the INTERMAP study. J Hum Hypertens. 2003;17(9):655–775.
community; intervention; public health; salt; sodium