Effect of salt intake on renal excretion of water in humans

FJ He, ND Markandu, GA Sagnella, GA MacGregor - Hypertension, 2001 - Am Heart Assoc
FJ He, ND Markandu, GA Sagnella, GA MacGregor
Hypertension, 2001Am Heart Assoc
Two studies were performed to determine the quantitative relationship between salt intake
and urinary volume (Uv) in humans. In study 1, 104 untreated hypertensives were studied on
the fifth day of a high-and a low-salt diet. The 24-hour Uv was 2.2 L (urinary sodium [UNa]
277 mmol) on the high-salt diet and decreased to 1.3 L (P< 0.001)(UNa 20.8 mmol) on the
low-salt diet. The reduction in 24-hour Uv was significantly related to the decrease in 24-
hour UNa (P< 0.001) and predicts that a 100-mmol/d reduction in salt intake would decrease …
Two studies were performed to determine the quantitative relationship between salt intake and urinary volume (Uv) in humans. In study 1, 104 untreated hypertensives were studied on the fifth day of a high- and a low-salt diet. The 24-hour Uv was 2.2 L (urinary sodium [UNa] 277 mmol) on the high-salt diet and decreased to 1.3 L (P<0.001) (UNa 20.8 mmol) on the low-salt diet. The reduction in 24-hour Uv was significantly related to the decrease in 24-hour UNa (P<0.001) and predicts that a 100-mmol/d reduction in salt intake would decrease 24-hour Uv by 367 mL. In study 2, 634 untreated hypertensives were studied on their usual diet. There was a significant relationship between 24-hour Uv and UNa (P<0.001). This predicts that a 100-mmol/d reduction in salt intake would decrease 24-hour Uv by 454 mL. The International Study of Salt and Blood Pressure (INTERSALT) of 1731 hypertensives and 8343 normotensives on their usual diet showed that 24-hour Uv was significantly related to UNa (P<0.001) and predicted that a 100-mmol/d reduction in salt intake would decrease 24-hour Uv by 379 and 399 mL in hypertensives and normotensives, respectively. These findings document the important effect that salt intake has on Uv. The recommended reduction in salt intake in the general population is from 10 to 5 g/d. This would reduce fluid intake in the population by ≈350 mL/d per person. This would have a large impact on the sales of soft drinks, mineral water, and beer.
Am Heart Assoc