***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Sodium restriction can reduce blood pressure in hypertensive patients . The present study indicates that if hypertension is well controlled then the reemergence of hypertension can be decreased by the use of a reduced sodium intake . The present paper demonstrates that in such patients on a normal salt diet  , 90 % become hypertensive within 6 months while only 40 % of people on a reduced sodium diet  become hypertensive . It is proposed that a high sodium intake activates a number of amplifiers that causes a shift of the dose-response curve to sodium to the left and if not prevented or interrupted leads to the development of hypertension The aim of the present study was to evaluate the effects of a normal-sodium ( 120 mmol sodium ) diet compared with a low-sodium diet ( 80 mmol sodium ) on readmissions for CHF ( congestive heart failure ) during 180 days of follow-up in compensated patients with CHF . A total of 232 compensated CHF patients ( 88 female and 144 male ; New York Heart Association class II-IV ; 55 - 83 years of age , ejection fraction < 35 % and serum creatinine < 2 mg/dl ) were r and omized into two groups : group 1 contained 118 patients ( 45 females and 73 males ) receiving a normal-sodium diet plus oral furosemide [ 250 - 500 mg , b.i.d . ( twice a day ) ] ; and group 2 contained 114 patients ( 43 females and 71 males ) receiving a low-sodium diet plus oral furosemide ( 250 - 500 mg , b.i.d . ) . The treatment was given at 30 days after discharge and for 180 days , in association with a fluid intake of 1000 ml per day . Signs of CHF , body weight , blood pressure , heart rate , laboratory parameters , ECG , echocardiogram , levels of BNP ( brain natriuretic peptide ) and aldosterone levels , and PRA ( plasma renin activity ) were examined at baseline ( 30 days after discharge ) and after 180 days . The normal-sodium group had a significant reduction ( P<0.05 ) in readmissions . BNP values were lower in the normal-sodium group compared with the low sodium group ( 685+/-255 compared with 425+/-125 pg/ml respectively ; P<0.0001 ) . Significant ( P<0.0001 ) increases in aldosterone and PRA were observed in the low-sodium group during follow-up , whereas the normal-sodium group had a small significant reduction ( P=0.039 ) in aldosterone levels and no significant difference in PRA . After 180 days of follow-up , aldosterone levels and PRA were significantly ( P<0.0001 ) higher in the low-sodium group . The normal-sodium group had a lower incidence of rehospitalization during follow-up and a significant decrease in plasma BNP and aldosterone levels , and PRA . The results of the present study show that a normal-sodium diet improves outcome , and sodium depletion has detrimental renal and neurohormonal effects with worse clinical outcome in compensated CHF patients . Further studies are required to determine if this is due to a high dose of diuretic or the low-sodium diet 28 patients who had a sustained diastolic blood pressure of 95 to 104 mm Hg and who had no treatment for it for at least 13 months before the trial , but who were otherwise unselected , took part in a r and omised controlled trial in which the effect of a restricted sodium diet was compared with that of a general health package . The general health package did not include any specific hypotensive procedures . Changes in blood pressure were measured at predetermined intervals over the course of a year . Within each group both systolic and diastolic blood pressure fell to a highly significant extent after a year , but there was no significant difference between the groups . It would thus seem that the antihypertensive effect of a restricted sodium diet may be related to the increased consultation and monitoring activity of such intervention rather than to the dietary manipulation itself Universal reduction in sodium intake has long been recommended , largely because of its proven ability to lower blood pressure for some . However , multiple r and omized trials have also demonstrated that similar reductions in sodium increase plasma renin activity and aldosterone secretion , insulin resistance , sympathetic nerve activity , serum cholesterol , and triglyceride levels . Thus , the health consequences of reducing sodium can not be predicted by its impact on any single physiologic characteristic but will reflect the net of conflicting effects . Some 23 observational studies ( > 360,000 subjects and > 26,000 end points ) linking sodium intake to cardiovascular outcomes have yielded conflicting results . In subjects with average  sodium intakes of less than 4.5 g/day , most have found an inverse association of intake with outcome ; in subjects with average intakes greater than 4.5 g/day , most reported direct associations . Finally , in two , a " J-shaped " relation was detected . In addition , three r and omized trials have found that heart failure subjects allocated to 1.8 g of sodium have significantly increased morbidity and mortality compared with those at 2.8 g. At the same time , a r and omized study in retired Taiwanese men found that allocation to an average intake of 3.8 g improved survival compared with 5.3 g. Taken together , these data provide strong support for a " J-shaped " relation of sodium to cardiovascular outcomes .  Sodium intakes above and below the range of 2.5 - 6.0 g/day are associated with increased cardiovascular risk . This robust body of evidence does not support universal reduction of sodium intake The present study set out to assess the feasibility of long-term moderate dietary sodium restriction in patients with mild hypertension in general practice . After screening and a run-in phase of 6 - 8 weeks , a total of 77 previously undiagnosed mildly hypertensive patients were identified . Half of them were r and omized to receive a few simple dietary instructions from their general practitioners in order to reduce salt usage ; the others were r and omized to receive no advice . The patients were followed up for 12 months with quarterly visits . A total of 56 patients ( 72.7 % ) completed the study , 26 on a low-sodium diet ( LD ) and 30 on their usual diet ( UD ) . At each visit in the diet phase , patients provided 24h urine , which was analysed for volume and sodium concentration in order to assess their sodium intake . Blood pressure , heart the rate and body weight were recorded . The mean urinary sodium excretion for all diet phase visits overlapped in the two groups ( 177.0 + /- 32.9 vs. 169.3 + /- 49.4 mEq/24h respectively in the LD and UD groups ) . Nevertheless the mean systolic and diastolic blood pressures for all diet phase visits were significantly lower in the LD than in UD group ( 144.2 + /- 11.1/91.6 + /- 6.4 and 148.0 + /- 13.7/95.6 + /- 4.7 mmHg respectively , P less than 0.01 ) . Our data suggest that it is not feasible at present to reduce sodium intake in mild hypertensives with simple and inexpensive dietary instructions , the only ones suitable for widespread application in general practice 1 . Three groups of young patients with borderline hypertension were studied for a 12 months period . The first was on a free sodium diet while the second was on a low-salt diet . The third group of patients underwent acute salt loading . 2 . After 12 months the group on free diet showed a significant increase of intralymphocytic sodium but no change in blood pressure was noted . Five patients who were re-checked after 24 months also had a significant increase in blood pressure . 3 . Patients treated with a low-salt diet showed a significant decrease of both intralymphocytic sodium concentration and blood pressure . 4 . After acute salt loading , borderline subjects with high intralymphocytic sodium showed a significant greater natriuresis whereas intralymphocytic sodium increased only in those subjects in whom it was initially normal 
    Output:
    
Our estimates of benefits from dietary salt restriction are consistent with the predicted small effects on clinical events attributable to the small blood pressure reduction achieved