There have been relatively few studies of the fundamental question of whether reducing an individual's -- or a population's -- salt intake will improve their health outcomes. Usually only one risk factor is considered: blood pressure. Other impacts confound blood pressure, itself a rather herterogeneous response. None of the outcomes studies is a controlled trial. Thus, policies embracing universal salt (or sodium) reduction have a weak foundation in the medical literature.
Here are the health outcomes studies reported publicly with links to the original sources where available:
Kagan, A. et. al. “Dietary and other risk factors for stroke in Hawaiian Japanese men.” Stroke, 1985; 16:390-396.
Alderman, M.H. et al. “Low urinary sodium associated with greater risk of myocardial infarction among treated hypertensive men. Hypertension 1995; 25:1144-1152.
Cutler, J.R., Presented May 30, 1997, at American Society of Hypertension annual meeting, San Francisco, CA. (unpublished).
Tunsall-Pedoe. “Comparison by prediction of 27 factors of coronary heart disease and health in men and women of the Scottish heart health study cohort study. British Medical Journal, 1997; 315:722-729.
See Table 6, age-adjusted hazard ratios.
Alderman M.H. et al. “Dietary sodium intake and mortality: the National Health and Nutrition Examination Survey (NHANES I).” Lancet 1998; 351:781-785
.
Valkonen, V-P. “Sodium and potassium excretion and the risk of acute myocardial infarction” Presented October 15, 1998 to the American Heart Association Scientific Sessions, Dallas, TX (unpublished).
Cohen, J.D. presentation to NHLBI Workshop on Sodium and Blood Pressure, January 28, 1999, Bethesda, MD
He, J. et al. “Dietary sodium intake and subsequent risk of cardiovascular disease in overweight adults.” Journal of the American Medical Association, 1999; 282:2027-2034.
Tuomilehto J. et al. “Urinary sodium excretion and cardiovascular mortality in Finland: a prospective study.” Lancet 2001; 357:848-51.
Commentary
Letters
(requires free registration)
Hooper, L. et al. “Systematic review of long term effects of advice to reduce dietary salt in adults.” British Medical Journal, 2002; 325:628-636.
Grobbee, D.E. et al. "Sodium and potasium intake and risk of cardiovascular events and all-cause mortality: the Rotterdam Study" presented to the 13th European Meeting on Hypertension in Milan, Italy, June 13-17, 2003 (published abstract)
Nagata, C. et al. "Sodium intake and risk of death from stroke in Japanese men and women." Stroke 2004; 35:1543-1547.
Cohen, H. et al. "Sodium intake and mortality in the NHANES II follow-up study." American Journal of Medicine 2006; 119,275.e7-275.e14
Shimazu, T. et al. "Dietary patterns and cardiovascular disease mortality in Japan: a prospective cohort study." International Journal of Epidemiology 2007; 36:1: 1-10.
Cook, N.R. et al "Long term effects of dietary salt reduction on cardiovascular disease outcomes: observational follow-up of the trials of hypertension prevention (TOHP)." British Medical Journal, doi:10.1126/bmj.39147.604896.55 (published 20 April 2007)
Geleijnse, J.M. et al. "Sodium and potassium intake and risk of cardiovascular events and all-cause mortality: the Rotterdam Study." European Journal of Epidemiology 2007; 10.1007/s10654-007-9186-2.
Larsson, S.C. et al. "Magnesium, calcium, potassium and sodium intakes and risk of stroke in male smokers." Archives of Internal Medicine, 2008; 168 (No 5), 459-465 (March 10, 2008).
Cohen, H.W. et al "Sodium intake and mortality follow-up in the Third National Health and Nutrition Examination Survey (NHANES III). Journal of General Internal Medicine (6) Online First (May 2008) -- likely to be published in the July edition
Taylor, R., et al "Reduced Dietary Salt for the Preventionof Cardiovascular Disease: A Meta-Analysis of Randomized Controlled Trials (Cochrane Review)." American Journal of Hypertension, 2011.
Stolarz-Skrzypek, et al "Fatal and Nonfatal Outcomes, Incidence of Hypertension, and Blood Pressure Changes in Relation to Urinary Sodium Excretion." The Journal of the American Medical Association (JAMA). 2011.