Blood Pressure Responses to Salt Hold Steady

A new study suggests that blood pressure (BP) responses to changes in dietary salt and potassium intake remains consistent over time, even years apart.

Researchers at Fu Wai Hospital (Beijing, China), Tulane University (New Orleans, LA, USA) and other institutions studied the long-term reproducibility of BP responses to dietary sodium and potassium intake by repeating interventions among 487 Chinese adults (median age 37, 50% male) at base and 4.5 years later. The identical dietary intervention protocol included a 7-day low-sodium feeding, a 7-day high-sodium feeding, and a 7-day high-sodium feeding with oral potassium supplementation. Three BP measurements were obtained during each of the 3 days of baseline observation and on days 5, 6, and 7 of each intervention period.

The results demonstrated that the correlation coefficients—the measures of how two linear entities move in lockstep—were moderate but highly significant for absolute systolic BP levels at the two time points. The correlation for absolute diastolic BP and mean arterial pressure levels followed a similar upward slope from baseline to high salt and potassium intake, but were less moderate. The study was published online on July 29, 2013, in Hypertension: Journal of the American Heart Association.

“The results indicate that blood pressure responses to changes in dietary sodium and potassium are not random phenomena, but stable and reproducible human characteristics during a relatively long time period,” concluded lead author Jiang He, MD, chair of the department of epidemiology at Tulane University, and colleagues.

An accompanying editorial by Peter de Leeuw, MD, PhD, and Abraham Kroon, MD, PhD, both of Maastricht University (The Netherlands) praised the authors for avoiding the dichotomous “salt-sensitive or resistant" approach, considering instead the degree of salt sensitivity as a continuous variable, which suggests that BP response to salt may have a setpoint, but is not fixed in time, thus demonstrating a relative constancy of the compensating mechanisms.

Related Links:
Fu Wai Hospital and Cardiovascular Institute
Tulane University