Rosa RM, Gallen IW, Young JB, Epstein FH, Landsberg L
Effects of a low-potassium diet on blood pressure and salt
excretion in black and white subjects
12th Annual ASH Meeting
Am J Hypertens
(Apr) 10:183A 1997
Background: The mechanism by which decreased dietary
potassium intake affects salt sensitivity has been demonstrated to
be
via an antinatriuretic effect. Previous studies have shown an
increase in mean arterial pressure, body weight and plasma volume
in
subjects placed on a potassium restricted diet. This study
attempts
to determine if racial differences in the response to potassium
restriction exist and if so, potential mechanisms responsible for
the
differences found.
Study Results: Twenty one normotensive Afro-American and
Caucasian subjects were studied on low (20 mmol/day) and high (90
mmol/day) potassium diets, each given for nine days. As expected,
potassium restriction increased mean arterial pressure, decreased
urinary sodium excretion and increased body weight. Afro-Americans
had lower urinary sodium and potassium excretion on both diets as
compared to Caucasians.
A second study evaluating the effects of three days of low and high
potassium intake on free water clearance and minimum urine
osmolality
was also performed. Potassium restriction decreased minimum
urinary
osmolality and increased free water clearance, suggesting to the
authors, that K restriction may be causing augmentation of sodium
reabsorption by way of the Na:K:2Cl cotransporter.
Comment: This study is interesting based on its findings of
changes in free water clearance and minimum urinary osmolality
during
low potassium intake. Racial differences are hard to discern from
the
data provided in the abstract given the small number of subjects
and
study design. Low potassium intake may also be affecting free
water
clearance and urinary osmolality by inducing a relative vasopressin
resistance rather than by altering activity of the Na:K:2Cl
cotransporter. Arlene Chapman, M.D., (University of Colorado,
Denver)
To go back use the BACK button on your browser.
Otherwise click on the desired link to this article below:
12th Annual ASH Meeting
H: Non drug therapy :
Dietary/electrolyte therapy
H: Special problems :
Ethnic populations