Salt intake, salt restriction, and primary (essential) hypertension
- Lawrence J Appel, MD, MPH
Lawrence J Appel, MD, MPH
- C. David Molina Professor of Medicine
- Johns Hopkins University School of Medicine
- Section Editors
- George L Bakris, MD
George L Bakris, MD
- Editor-in-Chief — Nephrology
- Section Editor — Hypertension
- Professor of Medicine
- The University of Chicago
- Norman M Kaplan, MD
Norman M Kaplan, MD
- Editor-in-Chief — Nephrology
- Section Editor — Hypertension
- Clinical Professor of Internal Medicine
- University of Texas Southwestern Medical Center
Sodium, commonly consumed as sodium chloride (table salt), is a major component of our food supply. Although sodium can be consumed in nonchloride forms (sodium bicarbonate [ie, baking soda] and monosodium glutamate [MSG]), salt provides approximately 90 percent of dietary sodium . In the United States, the quantity of sodium is typically reported as milligrams or millimoles of sodium, whereas in other parts of the world, in the scientific literature, and in recommendations, the quantity of sodium is reported as grams of salt (sodium chloride) rather than as sodium alone (to convert between units: grams of salt x 393 = milligrams of sodium; millimoles of sodium x 23 = milligrams of sodium).
Sodium is the principal cation of the extracellular fluid and functions as the osmotic determinant in regulating extracellular fluid volume and, therefore, plasma volume. Approximately 95 percent of the total sodium content of the body is found in extracellular fluid. Sodium is also an important determinant of the membrane potential of cells and the active transport of molecules across cell membranes. The concentration of sodium within the cell is typically less than 10 percent of that outside cell membranes, and an active, energy-dependent process is required to maintain this concentration gradient.
The relationship between sodium intake and blood pressure (BP), as well as the effects of sodium reduction in patients with uncomplicated primary hypertension (formerly called "essential" hypertension), are discussed in this topic review.
The importance of a reduced sodium intake, as well as fluid removal with diuretics, for volume management BP control in patients with chronic kidney disease is discussed elsewhere. (See "Overview of hypertension in acute and chronic kidney disease", section on 'Benefits of sodium restriction' and "Antihypertensive therapy and progression of nondiabetic chronic kidney disease in adults", section on 'Importance of salt intake'.)
The relationship of other factors to the development of hypertension, the evaluation of the hypertensive patient, and the management of hypertension in general and in specific subpopulations are discussed elsewhere. (See appropriate topic reviews.)To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
- Mattes RD, Donnelly D. Relative contributions of dietary sodium sources. J Am Coll Nutr 1991; 10:383.
- Institute of Medicine (U.S.). Panel on Dietary Reference Intakes for Electrolytes and Water. Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. National Academies Press, Washington, DC 2005. https://www.nap.edu/read/10925/chapter/1 (Accessed on December 12, 2016).
- Dahl LK. Salt and hypertension. Am J Clin Nutr 1972; 25:231.
- U.S. Department of Agriculture ARS, Beltsville Human Nutrition Research Center, Food Surveys Research Group (Beltsville, MD) and U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics (Hyattsville, MD). What we eat in America, NHANES 2011-2012 data: Dietary interview 2015. Sodium intake by age and gender. https://www.ars.usda.gov/northeast-area/beltsville-md/beltsville-human-nutrition-research-center/food-surveys-research-group/docs/wweianhanes-overview/ (Accessed on December 12, 2016).
- McGuire S. Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Washington, DC: US Departments of Agriculture and Health and Human Services, 2015. Adv Nutr 2016; 7:202.
- Lloyd-Jones DM, Hong Y, Labarthe D, et al. Defining and setting national goals for cardiovascular health promotion and disease reduction: the American Heart Association's strategic Impact Goal through 2020 and beyond. Circulation 2010; 121:586.
- Bertino M, Beauchamp GK, Engelman K. Long-term reduction in dietary sodium alters the taste of salt. Am J Clin Nutr 1982; 36:1134.
- Lawes CM, Vander Hoorn S, Rodgers A, International Society of Hypertension. Global burden of blood-pressure-related disease, 2001. Lancet 2008; 371:1513.
- Lewington S, Clarke R, Qizilbash N, et al. Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet 2002; 360:1903.
- Appel LJ, Brands MW, Daniels SR, et al. Dietary approaches to prevent and treat hypertension: a scientific statement from the American Heart Association. Hypertension 2006; 47:296.
- He FJ, MacGregor GA. Importance of salt in determining blood pressure in children: meta-analysis of controlled trials. Hypertension 2006; 48:861.
- Whelton PK, Appel LJ, Espeland MA, et al. Sodium reduction and weight loss in the treatment of hypertension in older persons: a randomized controlled trial of nonpharmacologic interventions in the elderly (TONE). TONE Collaborative Research Group. JAMA 1998; 279:839.
- Graudal NA, Hubeck-Graudal T, Jurgens G. Effects of low sodium diet versus high sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterol, and triglyceride. Cochrane Database Syst Rev 2017; 4:CD004022.
- Mozaffarian D, Fahimi S, Singh GM, et al. Global sodium consumption and death from cardiovascular causes. N Engl J Med 2014; 371:624.
- Effects of weight loss and sodium reduction intervention on blood pressure and hypertension incidence in overweight people with high-normal blood pressure. The Trials of Hypertension Prevention, phase II. The Trials of Hypertension Prevention Collaborative Research Group. Arch Intern Med 1997; 157:657.
- He FJ, MacGregor GA. Salt reduction lowers cardiovascular risk: meta-analysis of outcome trials. Lancet 2011; 378:380.
- Vasan RS, Beiser A, Seshadri S, et al. Residual lifetime risk for developing hypertension in middle-aged women and men: The Framingham Heart Study. JAMA 2002; 287:1003.
- Vollmer WM, Sacks FM, Ard J, et al. Effects of diet and sodium intake on blood pressure: subgroup analysis of the DASH-sodium trial. Ann Intern Med 2001; 135:1019.
- Intersalt: an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. Intersalt Cooperative Research Group. BMJ 1988; 297:319.
- Elijovich F, Weinberger MH, Anderson CA, et al. Salt Sensitivity of Blood Pressure: A Scientific Statement From the American Heart Association. Hypertension 2016; 68:e7.
- Johnson RJ, Herrera-Acosta J, Schreiner GF, Rodriguez-Iturbe B. Subtle acquired renal injury as a mechanism of salt-sensitive hypertension. N Engl J Med 2002; 346:913.
- Kurtz TW, DiCarlo SE, Pravenec M, Morris RC Jr. The American Heart Association Scientific Statement on salt sensitivity of blood pressure: Prompting consideration of alternative conceptual frameworks for the pathogenesis of salt sensitivity? J Hypertens 2017; 35:2214.
- Machnik A, Neuhofer W, Jantsch J, et al. Macrophages regulate salt-dependent volume and blood pressure by a vascular endothelial growth factor-C-dependent buffering mechanism. Nat Med 2009; 15:545.
- Kopp C, Linz P, Wachsmuth L, et al. (23)Na magnetic resonance imaging of tissue sodium. Hypertension 2012; 59:167.
- Wiig H, Schröder A, Neuhofer W, et al. Immune cells control skin lymphatic electrolyte homeostasis and blood pressure. J Clin Invest 2013; 123:2803.
- Suckling RJ, He FJ, Macgregor GA. Altered dietary salt intake for preventing and treating diabetic kidney disease. Cochrane Database Syst Rev 2010; :CD006763.
- Bray GA, Vollmer WM, Sacks FM, et al. A further subgroup analysis of the effects of the DASH diet and three dietary sodium levels on blood pressure: results of the DASH-Sodium Trial. Am J Cardiol 2004; 94:222.
- Sacks FM, Svetkey LP, Vollmer WM, et al. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group. N Engl J Med 2001; 344:3.
- Aburto NJ, Ziolkovska A, Hooper L, et al. Effect of lower sodium intake on health: systematic review and meta-analyses. BMJ 2013; 346:f1326.
- Pimenta E, Gaddam KK, Oparil S, et al. Effects of dietary sodium reduction on blood pressure in subjects with resistant hypertension: results from a randomized trial. Hypertension 2009; 54:475.
- Morris RC Jr, Sebastian A, Forman A, et al. Normotensive salt sensitivity: effects of race and dietary potassium. Hypertension 1999; 33:18.
- Graudal NA, Hubeck-Graudal T, Jürgens G. Effects of low-sodium diet vs. high-sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterol, and triglyceride (Cochrane Review). Am J Hypertens 2012; 25:1.
- He J, Gu D, Chen J, et al. Gender difference in blood pressure responses to dietary sodium intervention in the GenSalt study. J Hypertens 2009; 27:48.
- Slagman MC, Waanders F, Hemmelder MH, et al. Moderate dietary sodium restriction added to angiotensin converting enzyme inhibition compared with dual blockade in lowering proteinuria and blood pressure: randomised controlled trial. BMJ 2011; 343:d4366.
- Ram CV, Garrett BN, Kaplan NM. Moderate sodium restriction and various diuretics in the treatment of hypertension. Arch Intern Med 1981; 141:1015.
- Singer DR, Markandu ND, Sugden AL, et al. Sodium restriction in hypertensive patients treated with a converting enzyme inhibitor and a thiazide. Hypertension 1991; 17:798.
- Wright JA, Cavanaugh KL. Dietary sodium in chronic kidney disease: a comprehensive approach. Semin Dial 2010; 23:415.
- Weir MR, Hall PS, Behrens MT, Flack JM. Salt and blood pressure responses to calcium antagonism in hypertensive patients. Hypertension 1997; 30:422.
- Larochelle P. Renal tubular effects of calcium antagonists. Kidney Int Suppl 1992; 36:S49.
- Whelton PK, Appel LJ, Sacco RL, et al. Sodium, blood pressure, and cardiovascular disease: further evidence supporting the American Heart Association sodium reduction recommendations. Circulation 2012; 126:2880.
- Bibbins-Domingo K, Chertow GM, Coxson PG, et al. Projected effect of dietary salt reductions on future cardiovascular disease. N Engl J Med 2010; 362:590.
- Zhang D, Cogswell ME, Wang G, Bowman BA. Evidence of Dietary Improvement and Preventable Costs of Cardiovascular Disease. Am J Cardiol 2017; 120:1681.
- 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.
- Cook NR, Appel LJ, Whelton PK. Lower levels of sodium intake and reduced cardiovascular risk. Circulation 2014; 129:981.
- O'Donnell M, Mente A, Rangarajan S, et al. Urinary sodium and potassium excretion, mortality, and cardiovascular events. N Engl J Med 2014; 371:612.
- Cobb LK, Anderson CA, Elliott P, et al. Methodological issues in cohort studies that relate sodium intake to cardiovascular disease outcomes: a science advisory from the American Heart Association. Circulation 2014; 129:1173.
- Liu K, Stamler J. Assessment of sodium intake in epidemiological studies on blood pressure. Ann Clin Res 1984; 16 Suppl 43:49.
- Weaver CM, Martin BR, McCabe GP, et al. Individual variation in urinary sodium excretion among adolescent girls on a fixed intake. J Hypertens 2016; 34:1290.
- Rakova N, Jüttner K, Dahlmann A, et al. Long-term space flight simulation reveals infradian rhythmicity in human Na(+) balance. Cell Metab 2013; 17:125.
- Frohlich ED, Varagic J. Sodium directly impairs target organ function in hypertension. Curr Opin Cardiol 2005; 20:424.
- He FJ, MacGregor GA. A comprehensive review on salt and health and current experience of worldwide salt reduction programmes. J Hum Hypertens 2009; 23:363.
- Jula AM, Karanko HM. Effects on left ventricular hypertrophy of long-term nonpharmacological treatment with sodium restriction in mild-to-moderate essential hypertension. Circulation 1994; 89:1023.
- Gates PE, Tanaka H, Hiatt WR, Seals DR. Dietary sodium restriction rapidly improves large elastic artery compliance in older adults with systolic hypertension. Hypertension 2004; 44:35.
- Jablonski KL, Gates PE, Pierce GL, Seals DR. Low dietary sodium intake is associated with enhanced vascular endothelial function in middle-aged and older adults with elevated systolic blood pressure. Ther Adv Cardiovasc Dis 2009; 3:347.
- Joossens JV, Hill MJ, Elliott P, et al. Dietary salt, nitrate and stomach cancer mortality in 24 countries. European Cancer Prevention (ECP) and the INTERSALT Cooperative Research Group. Int J Epidemiol 1996; 25:494.
- Cappuccio FP, Kalaitzidis R, Duneclift S, Eastwood JB. Unravelling the links between calcium excretion, salt intake, hypertension, kidney stones and bone metabolism. J Nephrol 2000; 13:169.
- Lin PH, Ginty F, Appel LJ, et al. The DASH diet and sodium reduction improve markers of bone turnover and calcium metabolism in adults. J Nutr 2003; 133:3130.
- Amer M, Woodward M, Appel LJ. Effects of dietary sodium and the DASH diet on the occurrence of headaches: results from randomised multicentre DASH-Sodium clinical trial. BMJ Open 2014; 4:e006671.
- Chen L, Zhang Z, Chen W, et al. Lower Sodium Intake and Risk of Headaches: Results From the Trial of Nonpharmacologic Interventions in the Elderly. Am J Public Health 2016; 106:1270.
- Kleinewietfeld M, Manzel A, Titze J, et al. Sodium chloride drives autoimmune disease by the induction of pathogenic TH17 cells. Nature 2013; 496:518.
- Kotchen TA, Cowley AW Jr, Frohlich ED. Salt in health and disease--a delicate balance. N Engl J Med 2013; 368:2531.
- Strom BL, Anderson CA, Ix JH. Sodium reduction in populations: insights from the Institute of Medicine committee. JAMA 2013; 310:31.
- Stevens PE, Levin A, Kidney Disease: Improving Global Outcomes Chronic Kidney Disease Guideline Development Work Group Members. Evaluation and management of chronic kidney disease: synopsis of the kidney disease: improving global outcomes 2012 clinical practice guideline. Ann Intern Med 2013; 158:825.
- Cobb LK, Appel LJ, Anderson CA. Strategies to reduce dietary sodium intake. Curr Treat Options Cardiovasc Med 2012; 14:425.
- SODIUM INTAKE IN THE POPULATION
- SCIENTIFIC RATIONALE FOR DIETARY SODIUM REDUCTION
- Effect of sodium on blood pressure
- - Variability in the blood pressure response to sodium
- - Response to antihypertensive drugs
- Effects of sodium on cardiovascular disease
- Other adverse effects of excess sodium
- Hypothesized adverse effects of sodium reduction
- CLINICAL RECOMMENDATIONS
- Major society recommendations
- Guidance for health care providers
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS