Metabolic effects of strict salt restriction in essential hypertensive patients.
OBJECTIVE
Some observations suggest that a strict low-salt diet may induce unfavourable metabolic side-effects. The main aim of this study was to analyse the possible consequences of severe salt restriction in mildly hypertensive patients.


METHODS
The study was carried out through a randomized double-blind protocol.


METHODS
Forty-seven ambulatory patients proceeding from the hypertension unit were initially admitted: 17 were lost, and 30 non-diabetic mildly hypertensives (DBP 90-104 mmHg) with normal renal function completed the protocol.


METHODS
After a wash-out period, patients were maintained on a low-salt intake (2.8 +/- 1.0 g day-1 of NaCl) and placebo for 2 weeks, and the same diet and salt supplements (11.7 +/- 2.5 g day-1 of NaCl) for another 2 weeks, separated by a second wash-out period.


METHODS
At the end of each dietary period, blood pressure (BP) and body weight were measured, and a blood sample was taken for determination of routine serum chemistries, plasma lipid and apolipoprotein concentrations, immunoreactive insulin (IRI), and plasma renin activity (PRA). Urinary 24 h excretion of sodium and potassium were measured.


RESULTS
During the salt restriction period BP did not change, weight lowered, and PRA raised. There was a significant increase in serum level of creatinine, uric acid, IRI, total cholesterol and apo B, and a decrease in HDL cholesterol and apo A-I.


CONCLUSIONS
As previously suggested, these observations seem to indicate that strict salt restriction may cause, at least in the short-term, adverse metabolic changes in hypertensive patients.
Del Río
A
A
IMQ San Rafael, La Coruña, Department of Medicine, Faculty of Medicine, Santiago University, Santiago de Compostela, Spain.
Rodríguez-Villamil
J L
JL
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D001835:Body Weight; D003404:Creatinine / Q000097:blood; D004039:Diet, Sodium-Restricted / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000178:diet therapy / Q000378:metabolism* / Q000503:physiopathology; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000652:urine; D012083:Renin / Q000097:blood; D012964:Sodium / Q000652:urine; D014527:Uric Acid / Q000097:blood
D008055:Lipids; D014527:Uric Acid; D012964:Sodium; D003404:Creatinine; D012083:Renin; D011188:Potassium