Lowsodium Salt Substitutes and Blood Pressure

Summary

A Cochrane review [Abstract] 1 included 26 studies with a total of 34 961 adult subjects and 92 children. 16 studies randomized individual participants and 10 randomized clusters (families, households or villages). No studies in pregnant women were identified. Studies included only participants with hypertension (11/26), normal blood pressure (1/26), pre-hypertension (1/26), or participants with and without hypertension (11/26). The largest study included only participants with an elevated risk of stroke at baseline. Seven studies included adult participants possibly at risk of hyperkalaemia. All 26 studies specifically excluded participants in whom an increased potassium intake is known to be potentially harmful. More than half (14/26) were conducted in low- and middle-income countries.The proportion of sodium chloride replacement in the low-sodium salt substitutes (LSSS) interventions varied from approximately 3% to 77%. 23 studies investigated LSSS where potassium-containing salts were used to substitute sodium. Study duration ranged from 2 months to nearly 5 years.

LSSS compared to regular salt in adults: LSSS reduced diastolic blood pressure (DBP; MD -2.43 mmHg, 95% CI -3.50 to -1.36; 19 studies, n=20 830; statistical heterogeneity I² =88%), systolic blood pressure (SBP, MD -4.76 mmHg, 95% CI -6.01 to -3.50; 20 studies, n=21 414; statistical heterogeneity I² =78%), and non-fatal acute coronary syndromes (rate ratio 0.70, 95% CI 0.52 to 0.94; 1 study, n=20 995). LSSS also seemed to reduce non-fatal stroke (RR 0.90, 95% CI 0.80 to 1.01; 3 studies, n=21 250) and cardiovascular mortality (rate ratio 0.77, 95% CI 0.60 to 1.00; 3 studies, n=23 200), although these differences were not statistically significant. LSSS increased blood potassium slightly (MD 0.12 mmol/L, 95% CI 0.07 to 0.18; 6 studies, n=784) but no difference in hyperkalemia was observed (RR 1.04, 95% CI 0.46 to 2.38; 5 studies, n=22 849).