SALT RESTRICTION.txt
SALT RESTRICTION 

Report #6569 7/30/95
 
If you have high blood pressure, the odds are that restricting salt 
will lower your blood pressure only a minuscule amount. However, 
excessive salt intake may cause osteoporosis or a weakening of 
bones.

The theory is sound. The evidence is weak. The theory is that when 
you take in more salt than you need, the extra salt causes your body 
to hold more water which enlarges your blood volume and raises your 
blood pressure. However, the vast majority of Americans will not 
have their blood pressure rise after taking extra salt (1) and salt 
restriction does not lower blood pressure in people with normal 
blood pressure and it reduces blood pressure in people with high 
blood pressure only a minuscule amount. (2,3,4) On the other hand, 
low- fat diets and weight reduction lower high blood pressure to 
normal in most patients. (5) 

However, when you take in more salt than you need, urine levels of 
hydroxyproline rise considerably, showing that bone is being broken 
down./ Increasing salt intake increases calcium loss in the urine.
(6) Ingesting large amounts of salt also is associated with an 
increased risk of stomach cancer.(6)

Severely restricting salt intake by eating only low-salt foods can 
harm you by raising blood pressure. (7) and the bad LDL cholesterol 
in your bloodstream. (8,9). Salt deficiency causes your kidneys and 
adrenal glands to produce large amounts of the hormones, renin and 
aldosterone, which raise blood pressure. It is all right to stop 
adding salt to your food and cooking, but it is not reasonable to 
try to treat high blood pressure by seeking out and eating only 
foods that contain very little salt. If you have high blood 
pressure, lose weight if you are overweight. Most doctors will 
recommend salt restriction.

By Gabe Mirkin, M.D., for CBS Radio News 

1) Science 1982(April);216(2):38-40. 

2) Silman AJ, Locke C, Mitchel P. Humpherson P. Evaluation of the 
effectiveness of a low- sodium diet in the treatment of mild to 
moderate hypertension. Lancet 1983(May 28):1179. 

3) BR Davis, A Oberman, MD Blaufox, S Wassertheilsmoller, 
N Zimbaldi, K Kirchner, J Wylierosett, HG Langford. Lack of 
effectiveness of a low-sodium high-potassium diet in reducing 
antihypertensive medication requirements in overweight persons 
with mild hypertension. American Journal of Hypertension 1994(Oct);
7(10 Part 1):926-932. This study provides no support for the sole 
use of a low-sodium/high-potassium diet as a practical therapeutic 
strategy in maintaining blood pressure control in the moderately 
obese. 

4) JD Swales. Salt and blood pressure revisited. Journal of Human 
Hypertension 9: 6 (JUN 1995):517-5214. 

5) Wt and dietary fat more important. Hypertension 1991;
18(suppl 1):115-120. 

6) TFT Antonios, GA Macgregor. Salt intake: Potential deleterious 
effects excluding blood pressure. Journal of Human Hypertension 9: 
6 (JUN 1995): 511-515. 

7) M Egan, K. Stepniakowski, TL Goodfriend Renin and aldosterone 
are higher and the hyperinsulinemic effect of salt restriction 
greater in subjects with risk factors clustering. American Journal 
of Hypertension 7: 10 Part 1:OCT 1994:886-893. Greater activation of 
the renin-aldosterone axis may contribute to the rise of blood 
pressure and the larger increase of insulin during marked salt 
restriction in the high compared to low risk subjects. These 
findings may partially explain the variable effects of salt 
restriction on insulin levels in different studies. 

8) severe sodium restriction raises LDL. Klin Wochenschrift 1990;
68:664-668. 9) Klin Wochenschrift 1991 69 suppl):51-576383.