The influence of potassium intake on dipper and nondipper blood pressure status in an African-American adolescent population.

Abstract

OBJECTIVE: To examine the effects of a 3-week increase in dietary K+ on ambulatory blood pressure responses in healthy African-American adolescents who were classified as dippers (> 10% decrease in blood pressure from awake to asleep) versus nondippers (lt& 10% decrease in blood pressure from awake to asleep). SUBJECTS AND METHODS: Forty children and their parents were randomly assigned to a high-K+ diet (80 mmol/24 h) or a usual-diet control group. The treatment group demonstrated greater increases in dietary K+ and in K+ excretion than did the control group. Aproximately 30% of the adolescents were classified as nondippers consistently for classifications based on systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure. Subjects who were classified as nondippers had higher nocturnal blood pressures at baseline than did those classified as dippers. RESULTS: Dippers decreased awake blood pressures from pre- to post-treatment whereas nondippers unexpectedly increased awake blood pressures. Seventy-five and 80% of the nondippers switched dipping status in response to the high-K+ diet for classifications based on SBP and DBP, respectively. The control group showed a corresponding change in status of 28 and 50% for nondippers based on SBP and DBP classifications, respectively. Change in classifications based on mean blood pressure readings were relatively equal across the treatment and control groups. CONCLUSIONS: Overall, these results suggest that nondipping is prevalent in normotensive African-American adolescents and the rate is consistent with that found in adult populations. Furthermore, these results suggest that certain tyipes of high-K+ diets influence dipping status by increasing awake blood pressures among African-American adolescents who are classified as nondippers.