Recent studies that support limiting sodium to less than 1,500 milligrams a day
Study
Description
Conclusion
Strengths
Limitations
Dietary reference
intakes for water,
potassium, sodium,
chloride, and sulfate.
Appel LJ
The National
Academies Press
2005
A 600-plus-page
book from the
Institute of
Medicine that
analyzed research
on optimal water,
potassium,
sodium, chloride
and sulfate
levels.
Identified 1,500
mg/day as the
adequate intake
level of sodium for
adults, and 2,300
mg/day as an
upper level intake.
One of the most
complete reviews of
the scientific evidence
for goal-setting of
potassium, sodium,
chloride, sulfate and
water intake.
Based on a review of existing data
The importance of
population-wide
sodium reduction as a
means to prevent
cardiovascular
disease and stroke. A
call for action from
the American Heart
Association.
Appel LJ
Circulation
2011;123:1138-1143
This advisory
supplemented the
AHA’s original
policy paper
(Lloyd-Jones DM
et al, Circulation.
2010;121:586613), with a
focus on
justification of
the AHA’s
recommendation
for intake of
dietary sodium.-.
This metaanalysis
examined trends
for CVD events
and all-cause
mortality in 7
randomized
controlled trials
that had tested
the efficacy of a
sodium reduction
intervention.
The scientific
evidence indicates
that the dietary
sodium limit of
<1,500 mg per day
is associated with
a decreased risk of
cardiovascular
disease, stroke and
kidney disease.
Experts in the basic,
clinical and population
sciences present a
thoughtful analysis of
sodium reduction as it
relates to
cardiovascular disease.
Based on a review of existing data
One trial
conducted in
extremely sick
patients with heart
failure had little or
no relevance for
the general
population.
The analysis included
seven trials.
Reduced dietary salt
for the prevention of
cardiovascular
disease: a metaanalysis of
randomized
controlled trials.
Taylor RS
Am J Hypertens.
2011;24:843-853
In five trials, the
number of events
was lower among
those consuming
less sodium.
In one trial, the
number of
cardiovascular
events was similar
among participants
with lower and
higher sodium
intakes.
-more-
Several authors also
participated in the
AHA’s overall goals
paper.
Because the heart failure trial
included patients who already
were very sick and on medications
that effect sodium balance, the
results can’t be applied to the
general population.
The remaining six trials were
analyzed separately for those with
high and normal blood pressure.
As a consequence, the power to
recognize a statistically significant
effect of sodium reduction on
CVD risk was extremely limited.
A subsequent analysis (see He FJ,
below) that excluded the heart
failure trial and pooled data from
the remaining trials identified a
statistically significant 20 percent
decrease in cardiovascular events
among the lower-sodium group.
Circulation/Whelton – 2
Study Name
Lead Author
Publication
Date/Citation
Long-term effects of
dietary sodium
reduction on
cardiovascular
disease outcomes:
observational followup of the Trials of
Hypertension
Prevention (TOHP).
Cook NR
BMJ
2007;334:885-892
Effect of potassiumenriched salt on
cardiovascular
mortality and
medical expenses of
elderly men.
Chang HY
Am J Clin Nutr
2006;83:1289-1296
Salt reduction lowers
cardiovascular risk:
meta-analysis of
outcome trials.
He FJ
Lancet
2011;378:380-382
Description
Conclusion
Strengths
Limitations
This long-term,
follow-up study
included data
from two
previous
randomized
controlled
clinical trials to
examine the
long-term effects
of reduced
sodium
consumption on
cardiovascular
events among
adults 30-54 with
high blood
pressure.
This clinical trial
examined the
relationship
between lower
sodium,
potassiumenriched-salt
intake, medical
expenditures and
death from
cardiovascular
disease among
1,981 elderly
male veterans in
northern Taiwan.
The paper is a
quantitative
assessment of the
clinical trials in
the study by
Taylor, et. al.
(see description,
p. 2).
Sodium reduction
was associated
with an
approximately
25% reduction in
the risk of
cardiovascular
events.
The results were
analyzed according to
the participant’s
original randomized
assignment (lower
sodium intake or usual
care) and events were
tracked over a
prolonged period of
time (10-15 years),
increasing the
statistical power to
recognize an effect of
sodium reduction on
CVD morbidity and
mortality
Incomplete follow-up rate;
questionnaire format rather than
direct measurement of blood
pressure, weight, and sodium
intake.
Results
demonstrated that
elderly men who
switched to lower
sodium,
potassiumenriched salt lived
longer and spent
less on in-patient
care than men who
consumed regular
salt.
It’s the only
randomized, controlled,
clinical trial comparing
cardiovascular events
among patients who
consumed less sodium
(and more potassium)
compared to their
counterparts who
consumed their usual
(high sodium) diet.
Limited data, including no 24hour urine collections were
obtained.
After excluding a
confounding trial,
investigators
reported a
statistically
significant 20
percent decrease in
cardiovascular
events among the
lower-sodium
group.
See Taylor, et. al., p 2.
See Taylor, et. al., p. 2.
The trial only examined elderly
veterans in Taiwan, who may not
be similar to the general U.S.
population.
Consumer article:
Flawed science from JAMA. Why you should take the latest sodium study with a huge grain of salt. The Nutrition Source.
Harvard School of Public Health. 2012. www.hsph.harvard.edu/nutritionsource/salt/jama-sodium-study-flawed/index.html
Circulation/Whelton – 3
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