***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: Objective : To determine the blood pressure responses in elderly normotensive men and women to dietary sodium and to the diunsaturated fatty acid dihomogammalinolenic acid ( DGLA ) , which is derived from linoleic acid Design : Blood pressure responses were assessed in 66 subjects ( 36 male , 30 female ; mean age 65 years ) on two diets differing by approximately 70mmol/day sodium , combined with daily supplements of either 1 g DGLA or 1 g safflower oil  , giving a four-group parallel design . After a common period of salt restriction and salt supplementation , two sets of parallel groups continued with either salt or placebo tablets . The study was blinded , except for dietary adjustments based on 24-h urinary sodium excretion values measured once every 2 weeks . Blood pressures were also measured automatically once every 2 weeks Results : Urinary sodium excretion ( sodium intake ) correlated significantly with systolic and diastolic blood pressures . A strong interaction with sex ( P < 0.001 for systolic blood pressure ) reflected greater responsiveness in women to changing sodium intake . A second major determinant of blood pressure responsiveness was the waist : hip ratio , an index of central obesity ; this correlation was independent of the initial sodium intake , initial blood pressure or body mass index . The waist : hip ratio was a powerful predictor of blood pressure changes with sodium intake in women only ; women with and roid fat distribution were , similarly to men , less sensitive to dietary sodium . Daily supplements of 1 g DGLA doubled the concentration of DGLA in plasma but did not influence blood pressure Conclusions : Among elderly normotensive subjects , women responded to changes in sodium intake with greater changes in blood pressure than men did . Furthermore , this response was strongly related to the gynaecoid distribution of body OBJECTIVE To determine whether an increase in dietary potassium intake from natural foods reduces the need for antihypertensive medication in patients with essential hypertension . DESIGN R and omized , controlled trial with 1-year follow-up . SETTING Hypertension outpatient clinic of a university hospital . PATIENTS Fifty-four patients with well-controlled hypertension , 47 of whom completed 1 year of follow-up . INTERVENTION Patients were r and omly assigned to one of two groups and were given dietary advice aim ed at selectively increasing potassium intake ( group 1 ) or at keeping their customary diet unchanged ( group 2 ) . During a 1-year follow-up period , drug therapy was reduced in stepwise fashion , according to a fixed protocol , provided that blood pressure remained below 160/95 mm Hg . MAIN RESULTS Potassium intake was checked monthly by referring to 3-day food records and by measuring 24-hour urinary potassium excretion . Potassium intake increased in group 1 but did not change in group 2 ( P less than 0.001 ) . No change was observed in either urinary sodium excretion or in body weight . After 1 year , the average drug consumption ( number of pills per day ) relative to that at baseline was 24 % in group 1 ( 95 % Cl , 15 % to 32 % ) and 60 % in group 2 ( Cl , 44 % to 76 % ) ( P less than 0.001 ) . By the end of the study , blood pressure could be controlled using less than 50 % of the initial therapy in 81 % of the patients in group 1 ( Cl , 66 % to 96 % ) compared with 29 % of the patients in group 2 ( Cl , 10 % to 48 % ) ( P = 0.001 ) . Patients in group 1 ended the study with a lower number of reported symptoms compared with patients in the control group ( P less than 0.001 ) . CONCLUSION Increasing the dietary potassium intake from natural foods is a feasible and effective measure to reduce antihypertensive drug treatment Thirty-three patients with hypertension receiving drug treatment that included a potassium losing diuretic were r and omly allocated to 64 mmol of potassium  ( 14 patients ) or to no additional potassium supplementation  ( 19 patients ) . Potassium was administered as slow release potassium chloride . After 3 months , blood pressure fell by 5/1 mm Hg in the patients who received the supplements and by 7/4 mm Hg in those who did not receive them . The falls in pressure were not significantly different and the 90 % confidence limits for the effect of supplementation on diastolic pressure were : a fall of 2 mm Hg and a rise of 11 mm Hg , thus excluding an important hypotensive effect in these patients . Conversely , plasma creatinine fell by 11 % in the supplement group compared with a 6 % rise in the control group ( P less than 0.05 ) . Potassium supplementation , either by pharmacological preparations or by dietary manipulation , may prove to be desirable in patients on a potassium losing diuretic but should not be expected to lower blood pressure in such patients The aim of this study was to determine whether moderate restriction of dietary salt intake leads to an additional fall in blood pressure in treated hypertensive men who are asked to simultaneously reduce their usual alcohol intake . Sixty-three subjects entered an initial 2-week familiarization period during which they continued their usual alcohol intake and commenced a " low sodium " diet ( less than 60 mmol/day ) supplemented with 100 mmol sodium chloride per day as enteric-coated tablets . Subjects were then r and omly assigned to either drink a low alcohol beer alone for a 4-week period ( reducing their self-reported alcohol consumption from 537 to 57 ml/week ) or to continue their usual alcohol intake ( 543 versus 557 ml/week ) . Within the low and normal alcohol intake groups , subjects were assigned to either a low or normal sodium intake . The low sodium groups continued the sodium-restricted diet but were switched to placebo sodium chloride tablets for the 4 weeks . This result ed in a fall in the 24-hour urinary sodium excretion from 144 to 69 mmol/day . The normal sodium groups continued the low sodium diet but kept taking 100 mmol/day of the sodium chloride tablets , and their urinary sodium excretion remained unchanged ( 125 versus 142 mmol/day ) . Regular antihypertensive therapy was continued throughout . Fifty-nine subjects completed the trial . In those who reduced their alcohol intake there was a fall in both systolic blood pressure ( -5.4 mm Hg supine , p less than 0.01 ) and diastolic blood pressure ( -3.2 mm Hg supine , p less than 0.01 ) . ( ABSTRACT TRUNCATED AT 250 WORDS Potassium chloride ( KCl ) salt ( 65 mmol ) daily reduced BP from 153/104 to 146/101 mmHg in 32 hypertensive black females during a 6-week placebo controlled crossover study . The fall in BP was independent of the order of r and omization and was significant for systolic ( SBP ; P less than 0.01 ) and diastolic ( DBP ; P less than 0.05 ) pressure after 4 weeks . Analysis of the 95 % confidence intervals in this and in five other studies , two of which were reported as showing no beneficial effect , suggests that potassium supplementation does lower BP , but that the change is small and within the confidence levels of all six trials . Thus , apparent discrepancies in the literature are not genuine statistically OBJECTIVE To determine the effect of potassium supplementation on blood pressure in African Americans consuming a low-potassium diet . DESIGN R and omized , double-blind , placebo-controlled trial with two parallel arms . SETTING Community-based research site . PARTICIPANTS Eighty-seven healthy African Americans aged 27 to 65 years with a systolic blood pressure between 100 and 159 mm Hg and a diastolic blood pressure between 70 and 94 mm Hg . INTERVENTION During the 21-day intervention period , all participants were provided with a low-potassium diet ( 32 to 35 mmol/d ) . In addition to this diet , they were r and omly assigned to receive either potassium supplements ( 80 mmol/d ) or placebo . MAIN OUTCOME MEASURE Change in blood pressure in the potassium vs the placebo group , based on a total of nine blood pressure readings at three visits . Blood pressures were taken before and during the intervention by means of r and om-zero sphygmomanometry . RESULTS At baseline , the placebo and potassium groups were similar for mean blood pressure ( 127/78 vs 125/77 mm Hg ) , 24-hour urinary potassium excretion ( 50 vs 44 mmol ) , and all other variables measured ( all P > .05 ) . During the intervention , the net difference in 24-hour urinary potassium excretion between groups was 70 mmol . Compared with the placebo group , the potassium supplementation group experienced a net decline in systolic blood pressure of 6.9 mm Hg ( 95 % confidence interval , -9.3 to -4.4 mm Hg ; P < .001 ) and a decline in diastolic blood pressure of 2.5 mm Hg ( 95 % confidence interval , -4.3 to -0.8 mm Hg ; P = .004 ) . Simultaneous adjustment for differences in baseline characteristics only strengthened these estimates . CONCLUSIONS Potassium supplementation reduces blood pressure substantially in African Americans consuming a diet low in potassium . Increased potassium intake may play an important role in reducing blood pressure in this population at high risk for hypertension Epidemiological and experimental data suggest blood pressure-lowering effects of dietary potassium . A r and omized , double-blind clinical trial was used to assess blood pressure response to orally administered potassium , 120 mEq/day , and to placebo in 101 adults with mild hypertension .  Blood pressure was measured with a r and om-zero sphygmomanometer every 2 weeks of this 8-week trial . Systolic blood pressure in the potassium-treated group decreased by 6.4 + /- 13.7 ( SD ) mm Hg ( p less than or equal to 0.025 ) compared with 0.11 + /- 13.0 mm Hg in the placebo-treated group ( p = 0.96 ) . Diastolic blood pressure in the potassium-treated group decreased by 4.1 + /- 8.3 mm Hg ( p less than or equal to 0.05 ) compared with a 1.6 + /- 6.5 mm Hg decrease in placebo-treated subjects ( p = 0.09 ) . Baseline blood pressure of potassium-treated subjects was unexpectedly higher than that of controls . After correcting for baseline variation , blood pressure still decreased 3.4/1.8 mm Hg more in potassium recipients than in placebo recipients ( p = 0.14 and 0.24 , respectively ) . Blood pressure decreased by 19/13 mm Hg in five blacks taking potassium versus a 1/0 mm Hg increase in seven blacks taking placebo .  Compliance with the potassium regimen was 91.5 % by pill count ; only one subject discontinued treatment because of side effects . In conclusion , 120 mEq/day of microencapsulated potassium chloride was well tolerated in adults with mild hypertension . An antihypertensive effect of potassium can not be ruled out despite the fact that there was no statistically significant difference between potassium-treated and placebo-treated subjects after adjustment for differences in baseline blood pressure . ( ABSTRACT TRUNCATED AT 250 WORDS To determine the effects of potassium on blood pressure and factors affecting blood pressure , we conducted a r and omized , placebo controlled trial of a potassium chloride-based substitute for table salt in 23 patients with mild to moderate essential hypertension . In addition , the effects of potassium chloride on sodium balance were studied in 10 normal subjects .  Potassium loading with 100 mmol/day over five days in these normal subjects caused a cumulative negative sodium balance of 138 + /- 35 mmol , similar in degree to that achieved by severe dietary sodium restriction . However , two weeks of potassium treatment ( 100 mmol/day ) in patients with essential hypertension did not lower blood pressure ( BP ) either in the supine or upright positions ( potassium treatment : mean BP 108 + /- 3 lying and 113 + /- 3 mmHg st and ing ; placebo treatment : mean BP 109 + /- 3 lying and 115 + /- 3 mmHg st and ing ) . Patients found it difficult to tolerate the  potassium-based salt substitute in the dose given . We conclude that it is premature to recommend an increase in potassium chloride intake as treatment for raised blood pressure In 25 out patients with essential hypertension , sodium sensitivity , defined as the difference in mean arterial pressure ( delta MAP ) between 2 weeks of high-sodium ( 300 mmol per day ) and 2 weeks of low-sodium ( LS ) intake ( 50 - 100 mmol per day ) , was studied in relation to the plasma norepinephrine ( NE ) level , NE release , and pressor response to intravenous NE . In addition , forearm blood flow ( FBF ) was measured by plethysmography . There were two control periods of regular sodium intake , one of 4 weeks ' duration at the beginning of the study and one of 2 weeks ' duration at 
    Output:
    
In conclusion , reduced intake of sodium and increased intake of potassium could make an important contribution to the prevention of hypertension , especially in population s with elevated blood pressure