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A FACTORIAL STUDY OF FAT AND FIBRE CHANGES AND SODIUM RESTRICTION ON BLOOD PRESSURE OF HUMAN HYPERTENSIVE SUBJECTS
Author(s) -
Sciarrone S. E. G.,
Rouse I. L.,
Rogers P.,
Beilin L. J.
Publication year - 1990
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1990.tb01305.x
Subject(s) - sodium , blood pressure , medicine , endocrinology , placebo , cholesterol , dietary sodium , supine position , zoology , excretion , low sodium diet , chemistry , biology , renin–angiotensin system , alternative medicine , organic chemistry , pathology
SUMMARY 1. Diets used to reduce sodium intake often involve changes in fats and fibre which might themselves affect blood pressure and/or lipid metabolism. To evaluate the relative importance of these dietary changes for the management of hypertension we have studied the independent and additive effects of sodium restriction (60 mmol/day) and a low fat (30% energy), high P/S ratio (1.0), high fibre (30–50 g/day) ‘cholesterol lowering’ diet. 2. Ninety‐five hypertensives entered a four group parallel study with a factorial design. Following 5 weeks familiarization subjects [BP range 109/66–168/105 mmHg] were randomly assigned to either a ‘low sodium, cholesterol lowering’ diet or a ‘low sodium, cholesterol maintaining’ diet. Half the subjects in each group were then assigned to 100 mmol/day NaCl supplement and the remainder to placebo. These diets were continued for 8 weeks. Seventy‐nine of the 91 hypertensives who completed the study were on antihypertensive therapy throughout. 3. Mean urinary sodium excretion decreased from 137 (54 mmol/day ( n = 43) at baseline (B) to 52 (32) mmol/day ( n = 45, P = 0.0001) during intervention (I) in the low sodium groups and remained unchanged in the groups which received slow sodium (B = 129 [46], n = 43; I = 134 [29], n = 42). Diet record and plasma fatty acid analysis confirmed that the dietary aims of the study were achieved. 4. Sodium restriction reduced supine and standing systolic BP by a mean (± s.e.m.) of 6±2 and 6±4 mmHg, respectively ( P <0.005). The low fat/high fibre diet had no independent or additive effect on blood pressure reduction but reduced total and LDL cholesterol by an average of 0.74 and 0.59 mmol/L, respectively ( P <0.0001). 5. In terms of reducing overall risk of cardiovascular disease, diets which combine sodium restriction with measures to reduce LDL cholesterol would appear optimal.