Dose Dependent BP Lowering by Salt Reduction

A systematic review and meta-analysis of randomized trials concluded that the magnitude of blood pressure (BP) lowering achieved with sodium reduction showed a dose-response relation and was greater for older populations, non-white populations, and those with higher BP. Short term studies underestimate the effect of sodium reduction on BP. The analysis included 133 studies with 12 197 participants with estimates of sodium intake made using 24 hour urinary sodium excretion. The mean reductions (reduced sodium v usual sodium) of 24 hour urinary sodium, systolic BP (SBP), and diastolic BP (DBP) were 130 mmol, 4.26 mm Hg, and 2.07 mm Hg, respectively. Each 50 mmol reduction in 24 hour sodium excretion was associated with a 1.10 mm Hg reduction in SBP and a 0.33 mm Hg reduction in DBP. Reductions in BP were observed in diverse population subsets examined, including hypertensive and non-hypertensive individuals. For the same reduction in 24 hour urinary sodium there was greater SBP reduction in older people, non-white populations, and those with higher baseline SBP levels. In trials of less than 15 days’ duration, each 50 mmol reduction in 24 hour urinary sodium excretion was associated with a 1.05 mm Hg SBP fall, less than half the effect observed in studies of longer duration. The findings suggest that sodium reduction lowers BP in both hypertensive and non-hypertensive individuals, with greater effects in high risk subsets, could potentially avert or delay the development of hypertension with ageing as the association between sodium intake and BP is greater at older age. The physiological requirement for sodium in humans is less than 1 g a day, and the maximum daily intake of dietary sodium recommended by the World Health Organization is 2 g (5 g salt) for adults. Sodium intake of most populations is much higher. Source: https://www.bmj.com/