Dietary restriction of salt has been found to be as
effective as single drug therapies for hypertension. An altered dietary salt
intake could aid in the prevention and
treatment of diabetic kidney disease
About 75% of
cardiovascular disease (CVD) in diabetes may be attributed to hypertension.
Raised blood pressure (BP) is known to be the largest direct cause of death due
to the strokes, heart attacks and heart failure in diabetic patients. Diabetes makes it more likely to develop
high BP. Kidneys contain millions of tiny filters called nephrons.
Consistently high values of glucose, as it occurs in diabetes damage these
nephrons resulting in Diabetic kidney disease (DKD). DKD is the leading cause of chronic kidney disease (CKD), a condition
where there is progressive loss in renal function over a period of months or
It is known that our current consumption of salt is a major
factor in increasing BP. Salt sensitivity
is particularly high in diabetic patients. Public health guidelines
recommend reducing dietary salt intake to less than 5-6 g/day. A modest
reduction in salt intake lowers BP, irrespective of levels of blood pressure
being normal or raised. However the current knowledge of the role of salt in
regulating BP and its impact on DKD is limited to small studies. There are no standard criteria for high and
low salt diets.
A study was done to
evaluate the effects of salt restriction on the prevention and progression of
DKD. A meta-analysis of Randomised Control Trials (RCTs) of salt reduction was
performed. It included 13 studies including 254 patients with type 1 and type 2
diabetes. The results were published in Cochrane Reviews, a reliable source of
evidence-based health care.
It was found that reducing
salt intake by 8.5 g/day lowers BP by 7/3 mm Hg in type 1 and type 2 diabetes.
This effect is equivalent to that produced by a single drug therapy. Tight
control of BP in diabetics slows the progression of diabetic kidney disease. All diabetics should consider reducing salt
intake at least to less than 5-6 g/day. The recommendation of 5-6 g/day is
actually meant for the general population. Diabetics may consider lowering salt
intake to still lower levels.
The number of patients studied are not large but the results
have significant implications owing to the fact that it is often difficult in
clinical practice to control BP to the levels now recommended by guidelines. If a modest dietary restriction can be as
effective as drug therapy - the fact has significant preventive
implications to countries such as India
that have seen rising incidence of both diabetes and hypertension.
Citation: Suckling RJ, He FJ,MacGregor GA. Altered dietary
salt intake for preventing and treating diabetic kidney disease.
Database of Systematic
Reviews 2010, Issue 12. Art. No.: CD006763. DOI: