Effects of Potassium on Blood Pressure in Salt-Sensitive and Salt-Resistant Black Adolescents

Abstract

Abstract-This study examined the effects of increasing dietary potassium on ambulatory blood pressure nondipping status (Ͻ10% decrease in blood pressure from awake to asleep) and cardiovascular reactivity in salt-sensitive and salt-resistant black adolescents. A sample of 58 normotensive (blood pressure, 101/57Ϯ9/4 mm Hg) black adolescents (aged 13 to 16 years) participated in a 5-day low sodium diet (50 mmol/24 h) followed by a 10-day high sodium diet (150 mmol/24 h NaCl supplement) to determine salt-sensitivity status. Participants showed a significant increase in urinary sodium excretion (24Ϯ19 to 224Ϯ65 mmol/24 h) and were identified as salt-sensitive if their mean blood pressure increase was Ն5 mm Hg from the low to high sodium diet. Sixteen salt-sensitive and 42 salt-resistant subjects were then randomly assigned to either a 3-week high potassium diet (80 mmol/24 h) or usual diet control group. Urinary potassium excretion significantly increased in the treatment group (35Ϯ7 to 57Ϯ21 mmol/24 h). At baseline, a significantly greater percentage of salt-sensitive (44%) compared with salt-resistant (7%) subjects were nondippers on the basis of diastolic blood pressure classifications (PϽ0.04). After the dietary intervention, all of the salt-sensitive subjects in the high potassium group achieved dipper status as a result of a drop in nocturnal diastolic blood pressure (daytime, 69 versus 67 mm Hg; nighttime, 69 versus 57 mm Hg). No significant group differences in cardiovascular reactivity were observed. These results suggest that a positive relationship between dietary potassium intake and blood pressure modulation can still exist even when daytime blood pressure is unchanged by a high potassium diet. (Hypertension. 1999;34:181-186.)

The influence of varying dietary sodium content on circadian blood pressure profile in patients with salt-sensitive hypertension

“…Interestingly, many of dippers on a low sodium diet developed not desired non-dipping blood pressure pattern on a high sodium diet. This finding confirms a similar conclusion reported in Japan population [21], although in humans the blood pressure performance in response to high salt load can be modulated by dietary potassium intake [34]. The essential influence of dietary sodium on blood pressure profiles was demonstrated in experimental studies.…”

Altered circadian blood pressure profile in patients with active acromegaly. Relationship with left ventricular mass and hormonal values

“…23 In addition, there are data to suggest that hypertensive patients who are salt sensitive are more likely to be non-dippers than patients who are salt resistant. 24 Our results are in contrast with those observed by Minniti et al, 7 who in only one out of seven acromegalics with hypertension observed the absence of the physiological night-time decrease of BP, but they are in agreement with those observed by Terzolo et al, 8 who in five out of seven defined as hypertensives by ABPM found a non-dipper, altered night-day ratio for BP. In essential hypertensives it was observed that the ratio of fasting insulin to glucose was higher in non-dippers.…”

Endothelial dysfunction in normotensive salt-sensitive subjects

“…First, previous studies showed that potassium depletion exacerbates salt-induced elevation of BP. 29,30 However, in this study we were unable to determine whether a low potassium diet contributes to salt sensitivity due to the similar diet customs of the subjects in our study. Secondly, we demonstrated that endothelial dysfunction is a feature of NSS subjects.…”