Effect of reduced dietary sodium on blood pressure: a meta-analysis of randomized controlled trials

OBJECTIVE:- To ascertain whether restriction of dietary sodium lowers blood pressure in hypertensive and normotensive individuals. DATA SOURCES:- An English-language computerized literature search, restricted to human studies with Medical Subject Heading terms, "hypertension," "blood pressure," "vascular resistance," "sodium and dietary," "diet and sodium restricted," "sodium chloride," "clinical trial," "randomized controlled trial," and "prospective studies," was conducted. Bibliographies of review articles and personal files were also searched. TRIAL SELECTION:- Trials that had randomized allocation to control and dietary sodium intervention groups, monitored by timed sodium excretion, with outcome measures of both systolic and diastolic blood pressure were selected by blinded review of the methods section. DATA EXTRACTION:- Two observers extracted data independently, using purpose-designed forms, and discrepancies were resolved by discussion. DATA SYNTHESIS:- The 56 trials that met our inclusion criteria showed significant heterogeneity. Publication bias was also evident. The mean reduction (95% confidence interval) in daily urinary sodium excretion, a proxy measure of dietary sodium intake, was 95 mmol/d (71-119 mmol/d) in 28 trials with 1131 hypertensive subjects and 125 mmol/d (95-156 mmol/d) in 28 trials with 2374 normotensive subjects. After adjustment for measurement error of urinary sodium excretion, the decrease in blood pressure for a 100-mmol/d reduction in daily sodium excretion was 3.7 mm Hg (2.35-5.05 mm Hg) for systolic (P<.001) and 0.9 mm Hg (-0.13 to 1.85 mm Hg) for diastolic (P=.09) in the hypertensive trials, and 1.0 mm Hg (0.51-1.56 mm Hg) for systolic (P<.001) and 0.1 mm Hg (-0.32 to 0.51 mm Hg) for diastolic (P=.64) in the normotensive trials. Decreases in blood pressure were larger in trials of older hypertensive individuals and small and nonsignificant in trials of normotensive individuals whose meals were prepared and who lived outside the institutional setting. CONCLUSION:- Dietary sodium restriction for older hypertensive individuals might be considered, but the evidence in the normotensive population does not support current recommendations for universal dietary sodium restriction.     

The effect of dietary sodium intake on the blood pressure and cardiac output responses to angiotensin II in unanaesthetized rats

1. Dose-response curves for the pressor activity of angiotensin II have been determined in unanaesthetized rats receiving diets containing 2-5% (w/w) or 0-007% (w/w) sodium and administered in various sequences. 2. Dose-response curves were shifted to the left in rats on a high-, compared with a low-, sodium intake. This response was maintained for 7 days on changing from high to low sodium. 3. There was no difference in the relation between the fall of cardiac output and the rise of blood pressure in any of the experimental groups. 4. Dose-response curves for peripheral resistance showed the same directional change as seen for the pressor response in rats on high- and low-sodium diets. Since depression of cardiac output was proportional to the pressure rise, the absolute change in peripheral resistance was greater than the blood pressure response. The proportional changes were similar. 5. It is concluded that alterations in the pressor response to angiotensin caused by changes in sodium loading are attributable to changes in peripheral resistance and not to changes in the cardiac output response to the acute rise in blood pressure.     

Structural vascular changes in hypertension: role of angiotensin II, dietary sodium supplementation, blood pressure, and time

Previous studies have shown that a diet high in polyunsaturated fatty acids increases mammary tumor incidence in adult and pregnant mice and rats and in the female offspring. The present study investigated whether a high-fat diet alters the number of estrogen receptor (ER) binding sites and protein kinase C (PKC) activity in the mammary gland of these animals. In the female offspring, the effects of maternal exposure to a high-fat diet during pregnancy on development of the mammary epithelial tree were studied also. BALB/c mice were kept on a diet containing either 43% (high-fat) or 16% (low-fat) calories from corn oil, which consists mostly of n-6 polyunsaturated fatty acids, for 1 month. In adult female mice, a 6-fold increase in the number of ER binding sites and 2-fold increase in PKC activity were found in the mammary glands of the high-fat mice when compared with the low-fat mice. In pregnant mice, a high-fat diet increased ER binding sites by 61% and PKC activity by 51%. In contrast to adult and pregnant mice, females exposed to a high-fat diet only in utero through their pregnant mother exhibited a significantly reduced number of mammary ER binding sites by age 45 days (78% decrease) and a reduction in PKC activity by ages 30 and 100 days (44 and 20% decrease, respectively). The mammary epithelial tree of the high-fat offspring contained more terminal end buds and was less differentiated than that of the low-fat offspring. These findings show that consumption of a high-fat diet increases ER and PKC in the adult and pregnant mouse mammary gland, perhaps contributing to the fat-induced promotion of mammary tumorigenesis. In contrast, reduced ER and PKC following a high-fat exposure in utero may be associated with increased susceptibility to carcinogenesis, possibly due to an increased number of terminal end buds that are the sites of neoplastic transformation in the mammary gland.     

Acute effects of alcohol ingestion on blood pressure and erythrocyte sodium concentration

OBJECTIVE: To examine the acute effects of alcohol on blood pressure and erythrocyte cation concentrations in patients with essential hypertension. DESIGN: An alcoholic drink or an isocaloric control drink was given during supper in random order on different days, and blood pressure and erythrocyte cation concentrations were measured before and 2 h after the meal. METHODS: The subjects were 21 men with essential hypertension who habitually drank alcohol. Blood pressure was measured with a semi-automated sphygmomanometer, and erythrocyte cation concentrations were measured by flame photometry after haemolysis with distilled water. RESULTS: Blood pressure decreased after both drinks, but the decrease was significantly larger after the alcoholic drink than after the control drink. There was a significant difference between the changes in erythrocyte sodium caused by the alcoholic and the control drink. Furthermore, there were significant positive correlations between the fall in blood pressures and the decrease in erythrocyte sodium concentration. CONCLUSION: The predominant acute effect of alcohol ingestion in patients with hypertension is blood pressure reduction, and it may be associated with a decrease in intracellular sodium.     

Sensitivity of blood pressure and renin activation during sodium restriction

The objective of the present study was to explore the interrelationships among cumulative sodium loss, renin activation, and blood pressure changes during sodium restriction in essential hypertensive patients. Specifically, we wanted to know whether the degree of sodium sensitivity of blood pressure depends on renin activation during steady state or on initial renin activation during the first days of sodium restriction. Sixty-seven untreated essential hypertensive patients were admitted to a metabolic ward for 8 days and put on a sodium restricted diet of 55 mmol/d from the second to the last day. Urinary excretions of sodium, potassium, and creatinine were determined along with mean arterial pressure and weight during 7 days. Besides measurements in steady state condition (after 7 days), active plasma renin concentration, aldosterone, and catecholamines were also assessed during the first 3 days of sodium restriction. Analyzable data are available for 55 patients. Baseline sodium excretion and the activation of renin during the first 3 days both appeared to be predictors of total sodium loss after 7 days. Changes in blood pressure were not related to changes in sodium balance, but they were to baseline blood pressure, baseline norepinephrine, and renin activation during the early phase of sodium restriction. In addition, blood pressure appeared to fall more when the normal relationship between sodium loss and early (but not late) activation of renin was disturbed. We conclude that sodium sensitivity of blood pressure during sodium restriction is associated with a relative unresponsiveness of the renin system during the early phase of sodium loss rather than to absolute renin levels during steady state.     

Association between blood pressure and dietary factors in the dietary and nutritional survey of British adults

During the last few decades, the industrial production and use of Cd resulted in the release of significant quantities of Cd into the environment. Concern about health risks of human exposure to this toxic metal, which may be contained in soil and other environmental compartments, has increased significantly in recent years. Soil ingestion is a potentially important pathway of exposure to soil-absorbed environmental contaminants, especially for young children exhibiting hand-to-mouth behavior. Health risk assessments are usually based on unchanged bioavailability of soil-absorbed pollutants, e.g., heavy metals, neglecting interactions of metals with the soil matrix, which may lead to relatively lower bioavailability. This study was conducted to determine the bioavailability of Cd absorbed to soil in rats. Eight-week-old male Lewis rats were given either a soil polluted with CdCl2 (150 micrograms Cd/rat) dissolved in 5% gun acacia or an equal amount of Cd as CdCl2 dissolved in saline. Control rats were gavaged with isotonic saline. Cd concentrations in liver, kidney, brain, heart, and blood, as well as Cd content of urine and feces were analyzed using graphite furnace atomic absorption spectrometry. Tissue Cd concentrations in soil-treated animals were significantly lower than the tissue concentrations in the Cd-saline group; in the liver and kidneys of the Cd-saline and Cd-soil groups, 4 and 2.7% respectively, of the original doses were recovered. Relative bioavailability, calculated on the basis of blood Cd levels for the Cd-soil group as compared to the Cd-saline group, appeared to be 43%. No differences in the excretion pattern of Cd into feces were observed between the Cd-saline and Cd-soil groups. After 6 days, over 91% of the original dose was recovered in the feces of both Cd-treated groups. Cd excretion via urine was very low, but in the Cd-soil group a significant increase in urinary Cd was observed as compared to the control group. However, the amount of Cd excreted into urine of the Cd-soil group during the experimental period corresponded to only 0.01% of the original dose. In the Cd-saline group, no additional Cd was excreted into urine as compared to the control group. These results indicate that the soil matrix significantly reduced the absorption of Cd in the gastrointestinal tract. Consequently, exposure assessment models, assuming an unaffected bioavailability of soil-absorbed Cd, overestimate the internal dose and thereby overestimate health risks associated with direct ingestion of soil particles.     

Comments on a meta-analysis of the relation between dietary calcium intake and blood pressure

The role of dietary calcium in the etiology of hypertension is controversial. In 1995, Cappuccio et al. (American Journal of Epidemiology,1995;142:935-45) examined this issue in a meta-analysis of observational studies published between 1983 and 1993. The author of the present paper reviewed the original studies underlying this meta-analysis and discovered that data from one study had been inappropriately extracted and converted, leading to an understatement of the calcium-blood pressure relation by a factor of about 30. This review also raised questions about the extraction and conversion of data from several other studies and about the statistical methods used. The author repeated the meta-analyses and discovered an unadjusted regression slope between dietary calcium and systolic blood pressure of -0.34 mmHg/100 mg per day (95% confidence interval (CI) -0.46 to -0.22) for men, -0.15 mmHg/100 mg per day (95% CI -0.19 to -0.11) for women, and -0.39 mmHg/100 mg per day (95% CI -0.47 to -0.31) for men and women. For diastolic blood pressure, the pooled regression slope for men was -0.22 mmHg/100 mg per day (95% CI -0.32 to -0.13), while for women it was -0.051 mmHg/100 mg per day (95% CI -0.090 to -0.012); for men and women it was -0.35 mmHg/100 mg per day (95% CI -0.67 to -0.02). These slopes are still modest but are larger than those reported in the original analysis. However, since all of these analyses were based on zero-order correlations or regressions, extreme caution must be exercised in interpreting the results.     

Effects of dietary fat saturation on eicosanoid production, platelet aggregation and blood pressure

The effects of dietary fat saturation on eicosanoid urinary excretion, platelet aggregation (PA) and blood pressure (BP) were studied in 42 healthy subjects. They consumed four consecutive diets differing in their fat saturation [saturated (SFA); monounsaturated (MUFA); polyunsaturated n-6 (PUFA n-6); and polyunsaturated n-6/n-3, (PUFA n-3)]. Each diet period lasted 5 weeks. There were no differences in 24-h 2,3-dinor-6- keto-prostaglandin F1 alpha excretion among dietary periods. A significant effect was noted regarding the excretion of 11-dehydro-thromboxane B2 (P < 0.0001). During the PUFA n-6 phase the excretion was significantly higher than during SFA and MUFA periods. Dietary fatty acid composition had a significant effect on ADP (1 mumolL-1) and collagen (2 mgL-1) induced PA. Dietary fat also had a significant effect on systolic and diastolic blood pressure (P < 0.0001). Both were significantly higher during the SFA period than during the other three periods. Our findings suggest that changes in dietary fatty acids may have mild, but significant, effects on eicosanoid production, platelet aggregation and blood pressure.     

Endogenous sodium pump inhibitors and blood pressure regulation: an update on recent progress

Rapid progress has occurred recently in understanding the origin, chemistry, synthesis, control, and actions of endogenous materials that may be ligands for the cardiac glycoside binding site on the mammalian sodium pump (Na,K-ATPase). The present paper reviews this progress and examines in detail the evidence supporting ouabain-like and bufodienolide-like compounds as functioning in endogenous control of sodium pump activity, renal sodium excretion, blood pressure, and cardiovascular contractility. Other novel compounds identified in this search as potentially influencing natriuresis and blood pressure are also discussed.     

The relationship of blood lead and dietary calcium to blood pressure in the normative aging study

BACKGROUND: Previous studies have demonstrated a positive relationship between elevated blood lead (BPb) and blood pressure (BP), but few have additionally examined the role of dietary calcium. METHODS: The cross-sectional relationship between BPb and BP and the possible protective influence of increased dietary calcium on that relationship was examined among 798 male participants in the Normative Aging Study (NAS), a cohort of older men with relatively low BPb levels. RESULTS: The age range of these subjects was 43-93 years (mean = 66.1, SD = 7.4 years) and blood lead concentrations ranged form 0.5 to 35 mcg/dl (median = 5.6 mcg/dl). For the cohort overall, neither ln blood lead nor dietary calcium were significantly correlated with BP. In multivariate linear regression analyses that adjusted for age, body mass index, dietary calcium intake (adjusted for total calorie intake), alcohol intake, sitting heart rate, kilocalories/week expended in exercise, haematocrit, and smoking status, a unit increase in ln BPb predicted an increase on 1.2 mmHg diastolic blood pressure (DBP) (95% CI : 0.11, 2.2; P = 0.03). Adjusted calcium intake of 800 mg/day predicted a decrease of 3.2 mmHg systolic blood pressure (SBP) (95% CI : -5.6, -0.24, P = 0.03). There was no evidence of an interaction between dietary calcium intake and blood lead on BP. When the analyses were restricted to those men <=74 years old, a unit increase in ln BPb predicted an increase of 1.6 mmHg DBP (n = 681; 95% CI : 0.42, 2.7; P = 0.007). However, when men on antihypertensive medication (AHM) were excluded from the analyses, ln BPb was not significantly associated with increased DBP nor was adjusted calcium significantly associated with SBP. CONCLUSIONS: The study did support the hypothesis that increased BPb was associated with increased DBP in a cohort of older men with low blood lead, but there was no evidence of interaction between BPb and dietary calcium on BP. However, the relationship between increased BPb and DBP did not hold when those on anti-hypertensive medications were excluded.     

Influence of dietary fats upon systolic blood pressure in the rat

Studies were performed to determine whether feeding diets with differing fatty acid content and composition had an influence on systolic blood pressure in the rat. Weanling male rats were fed standard laboratory chow (2.9% fat in total), or synthetic diets (10% fat in total) containing fish oil, butter, coconut oil or corn oil, for 5 weeks. Coconut oil and butter diets were rich in saturated fatty acids, whilst fish oil and corn oil were rich in the n-3 and n-6 unsaturated fatty acids respectively. Systolic blood pressure was measured using an indirect tail-cuff method at the end of the feeding period, and compared to a group of weanling rats. Feeding the different diets did not alter the growth of the rats, so all animals were of similar weights at the time of blood pressure determination. Control (chow fed) animals, at nine weeks of age, had higher systolic blood pressures than the weanling, baseline control group. Fish oil fed rats had similar pressures to the chow fed rats. Corn oil fed rats had significantly lower systolic pressures than the controls. The rats led the diets rich in saturated fatty acids (butter and coconut oil) had significantly higher blood pressures than all other groups. Systolic blood pressure was found to be significantly related to the dietary intakes of saturated and unsaturated fatty acids. The dietary intake of linoleic acid was significantly higher in corn oil fed rats than in other groups. Systolic blood pressure was inversely related to linoleic acid intake. Feeding a diet rich in saturated fatty acids significantly increases blood pressure in the rat. A high intake of n-6 fatty acids, and in particular linoleic acid, appears to have a hypotensive effect. Prenatal exposure of the rats to a maternal low protein diet, abolished the hypertensive effects of the coconut oil diet and the hypotensive effect of the corn oil diet upon young adult females. The intrauterine environment may, therefore, be an important determinant of the effects of these fatty acids on blood pressure in later life.     

Chronic sodium balance and blood pressure response to captopril in conscious mice

The influence of chronic administration of the converting enzyme inhibitor captopril on blood pressure and sodium balance was evaluated in conscious Swiss Webster mice. Arterial pressure was measured with chronic indwelling catheters, and sodium balance was determined by infusing sodium intravenously in isotonic saline and collecting urine 24 h/d. Experiments to validate sodium balance measurements in mice demonstrated recovery of 100+/-3% of sodium intake under steady-state conditions (n=20 mice on 70 individual days, sodium intake range 160 to 1000 micromol/d). It was further demonstrated that mean arterial pressure, heart rate, and body weight were unaltered from 115+/-7 mm Hg, 646+/-12 bpm, and 34+/-0.6 g, respectively, as sodium intake was increased stepwise from 150 to 900 micromol NaCl per day. An additional validation group (n=7) demonstrated that daily and cumulative sodium balance can be accurately determined during and after the intravenous administration of an agent known to alter renal sodium handling (furosemide 50 mg. kg-1. d-1). Experiments were then performed to examine the influence of intravenous captopril infusion (40 mg. kg-1. d-1, n=7) in mice in which the daily sodium intake was fixed at approximately 200 micromol/d. This dose of captopril was determined to significantly decrease the pressor response to a 10-ng bolus of angiotensin I (Ang I) from 24+/-5 in the control state to 6+/-2 mm Hg (n=5). After 5 days of infusion of the converting enzyme inhibitor, mean arterial pressure significantly fell from 114+/-3 to 58+/-2 mm Hg, body weight significantly decreased from 36+/-1 to 33+/-1 g, and cumulative sodium balance significantly decreased to -270+/-55 micromol. These parameters returned toward control during 5 postcontrol days. Results of this study demonstrate that accurate sodium balance measurements can be obtained from individual conscious mice over a 5-fold range of sodium intake. The experiments also indicate that converting enzyme inhibition has a potent influence to lower blood pressure in normal mice; the hypotensive response appears to be due in part to increased urinary sodium excretion.     

Effects of varying sodium intake on blood pressure and renin-angiotensin system in subtotally nephrectomized rats

In rats in which the renal mass had been reduced by 70 per cent, the effects of varying sodium intake on blood pressure, serum electrolytes, renin-angiotensin system, and some other parameters that were modified simultaneously were studied. Within 4 weeks, a high sodium diet (750 mEa. per kilogram) resulted in marked hypertension, whereas a standard sodium diet (150 mEq. per kilogram) elevated the blood pressure only slightly. A low sodium diet (less than 0.2 mEq. per kilogram) prevented the rise in blood pressure. In the hypertensive group, the hematocrit values were markedly decreased, indicating the expansion of extracellular and intravascular spaces. The compensatory renal hypertrophy was accelerated by the high sodium diet and retarded during restriction. During low sodium intake, the serum concentration of sodium was diminished and that of potassium elevated. During the high sodium diet, the sodium concentration was unchanged, but the potassium concentration was decreased. Subtotal nephrectomy diminished the plasma angiotensin II concentration, and the renin content of the kidney remnant was lower than that of the kidneys from control animals. Sodium restriction stimulated the renin angiotensin system markedly, whereas high sodium intake suppressed it. After subtotal nephrectomy, elevation of blood pressure, renal hypertrophy, and suppression of the renin-angiotensin system are closely related to sodium intake.     

Effect of cross-fostering on neonatal sodium balance and adult blood pressure in the spontaneously hypertensive rat

1. The aim of the present study was to compare electrolyte handling in naturally reared neonatal spontaneously hypertensive rats (SHR) with those reared by a Wistar-Kyoto (WKY) rat foster mother (denoted SHRX), as cross-fostering SHR pups to a WKY rat dam lowers adult blood pressure in the SHR. 2. The electrolyte content of WKY rat and SHR dams' milk was determined and electrolyte intake and urinary excretion rates were calculated in both naturally reared and cross-fostered WKY rat and SHR pups. 3. The milk sodium concentration fell in both strains (WKY rat: 31.8 +/- 2.0 to 15.2 +/- 1.2 mmol/L; SHR 31.9 +/- 2.5 to 18.2 +/- 1.6 mmol/L; P < 0.001), as did potassium (P < 0.001), over lactation, but there were no differences between strains. Calcium and magnesium concentrations increased (P < 0.001), although SHR dam's milk contained less calcium (P < 0.001) than that of WKY rat dams during the third week of lactation. 4. Spontaneously hypertensive rat pups ingested less milk (P < 0.05) than WKY rat pups; therefore, their cumulative sodium intake over postnatal days 4-15 was significantly lower than that of WKY rat pups (WKY rat vs SHR: 84.4 +/- 3.6 vs 59.7 +/- 2.6 mumol/g bodyweight, respectively; P < 0.05) and fostered SHRX pups (77.7 +/- 7.0 mumol/g bodyweight; P < 0.05). Potassium and magnesium intakes were comparable between SHR, WKY rat and SHRX pups, but SHR pups ingested significantly less calcium than either WKY rat pups (136.1 +/- 6.4 vs 200.1 +/- 9.5 mumol/g bodyweight, respectively; P < 0.05) or SHRX pups (200.0 +/- 18.0 mumol/g bodyweight; P < 0.05). 5. These data show that the neonatal SHR experiences a period of sodium deficiency during the developmental stage when cross-fostering is effective in lowering blood pressure. This is consistent with the reported up-regulation of the renin-angiotensin system observed in SHR at this time and may have a long-term influence on blood pressure.     

Effects of lisinopril on stress-induced peak blood pressure and sodium excretion: a double-blind controlled study

Hirudin is an anticoagulant originally extracted from the leech Hirudo medicinalis. Using recombinant DNA technology a new compound, recombinant desulphato hirudin CGP 39393 has now been produced. The aim of this study was to determine the maximum tolerated dose in patients undergoing elective hip replacement. This open safety trial represents, to our knowledge, the first experience of recombinant hirudin in orthopedic patients. In this study 48 patients undergoing primary total hip replacement were included and the safety of subcutaneous injections of 10, 15, 20 and 40 mg CGP 39393 twice daily, was evaluated. Prophylaxis was started immediately pre-operatively and continued for 8-10 days. A mandatory bilateral phlebography was performed at the end of the prophylactic treatment period and a clinical follow-up was done 6 weeks after surgery. A major bleeding event occurred in the first 3 patients receiving 40 mg CGP 39393 b.i.d. and the prophylaxis regimen at this dosage level was therefore discontinued. Median values of total blood loss and requirements of blood transfusion in the patients receiving 10-20 mg CGP 39393 were similar to those reported in previous studies on total hip replacement performed at the same centre, using other prophylactic drugs. Deep vein thrombosis (DVT) was confirmed by phlebography in 5 out of 12 patients in the 10 mg group (41.7%, 95% confidence limits [CL]: 15.2-72.3%), 1 out of 11 patients in the 15 mg group (9.1%, CL: 0.23-41.3%) and 2 out of 20 patients in the 20 mg group (10.0%, CL: 1.2-31.7%) during the prophylaxis period. CGP 39393 was safe and well tolerated, when administered as subcutaneous injections of 10-20 mg twice daily. The dose level of 40 mg CGP 39393 twice daily resulted in serious disturbance of the hemostasis in patients after hip prosthesis surgery.     

A comparative study of blood pressure and sodium intake in Belgium and in Korea

A comparative blood pressure and sodium excretion were higher in Korea than in Belgium. By multiple regression and covariance analysis an independent positive association between sodium and blood pressure and a negative correlation between potassium and blood pressure were found in some population subgroups and in the total population studied in Korea. In Belgium a positive association between sodium and blood pressure was found when higher powers of age, height, weight and sodium were included in the analysis. The independent influence of sodium on blood pressure was relatively small, amounting to about 2 mm Hg of pressure rise for an increase in 24-h excretion of 100 mmol of sodium.     

Influence of dietary sodium restriction on lipid metabolism

The possible increase in total and low-density lipoprotein cholesterol following severe restriction of dietary NaCl was reported in 1990 and and 1991 from three experiments, one in the United States and two in Germany. Each of these experiments lasted only 1 week. To evaluate the clinical side effects we analyzed data collected from patients who completed a course of NaCl-restricted weight reduction at the Duke Diet and Fitness Center. Observations of lipid changes are not available for periods of less than 3 weeks; however, we were able to collect data on lipid and lipoprotein changes from 556 participants 25 days after they were referred for weight reduction. Total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels returned to normal in the majority of obese patients. In our slightly longer observation period in patients on a 1000 mg NaCl restricted diet we found no evidence of hyperlipidemic side effects. We believe that the hyperlipidemia resulting from severe sodium restriction in non-hypertensive, normal-weight individuals is not relevant to the problem of nonpharmacological and diuretic treatment of obese hypertensive patients. In clinically healthy, normal-weight, normotensive individuals severe salt restriction serves no practical or therapeutic purpose.