An in-depth review of the evidence linking dietary salt intake and progression of chronic kidney disease.
BACKGROUND
Dietary salt has been debated for decades as having a potentially deleterious influence on human health.


OBJECTIVE
To determine the quality of research and the relationship between dietary salt and markers for progression of kidney disease.


METHODS
Data sources included 7 electronic databases comprehensively searched for literature published between January 1, 1966, and August 31, 2004, and a manual search of bibliographies of relevant papers, and consultation with experts in the field. Differences between the paired reviewers were reconciled through consensus or by a content expert.


RESULTS
Sixteen studies met the inclusion-exclusion criteria and were identified for review; however, the study methodologies were extremely heterogeneous. Conclusions commonly cited in the studies include: variations in salt consumption are directly correlated with albuminuria, and an increase in salt consumption is associated with an acute increase in glomerular filtration rate, while a reduction in salt consumption may slow the rate of renal function loss.


CONCLUSIONS
The available published information, while highly variable in methods and quality, suggests that variations in dietary salt consumption directly influence albuminuria, with increasing salt intake associated with worsening albuminuria; however, results are inadequate and conflicting on the effects of dietary salt consumption on renal function, especially over a prolonged time. There was no evidence of a detrimental effect of reduced salt intake. On the other hand, there is consistent experimental evidence to link increased salt exposure with kidney tissue injury. On the basis of these data, we believe that dietary salt restriction should be considered in patients with chronic kidney disease.
Jones-Burton
Charlotte
C
Department of Medicine, Division of Nephrology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Mishra
Shiraz I
SI
Fink
Jeffrey C
JC
Brown
Jeanine
J
Gossa
Weyinshet
W
Bakris
George L
GL
Weir
Matthew R
MR
D015897:Comorbidity; D018450:Disease Progression; D004435:Eating; D019317:Evidence-Based Medicine; D006801:Humans; D006977:Hypertension, Renal / Q000453:epidemiology*; D007676:Kidney Failure, Chronic / Q000453:epidemiology*; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods*; D017673:Sodium Chloride, Dietary; D013223:Statistics as Topic
D017673:Sodium Chloride, Dietary