***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: Abstract —Single dose administration of dietary inorganic nitrate acutely reduces blood pressure ( BP ) in normotensive healthy volunteers , via bioconversion to the vasodilator nitric oxide . We assessed whether dietary nitrate might provide sustained BP lowering in patients with hypertension . We r and omly assigned 68 patients with hypertension in a double-blind , placebo-controlled clinical trial to receive daily dietary supplementation for 4 weeks with either dietary nitrate ( 250 mL daily , as beetroot juice ) or a placebo ( 250 mL daily , as nitrate-free beetroot juice ) after a 2-week run-in period and followed by a 2-week washout . We performed stratified r and omization of drug-naive ( n=34 ) and treated ( n=34 ) patients with hypertension aged 18 to 85 years . The primary end point was change in clinic , ambulatory , and home BP compared with placebo . Daily supplementation with dietary nitrate was associated with reduction in BP measured by 3 different methods . Mean ( 95 % confidence interval ) reduction in clinic BP was 7.7/2.4 mm Hg ( 3.6–11.8/0.0–4.9 , P<0.001 and P=0.050 ) . Twenty-four-hour ambulatory BP was reduced by 7.7/5.2 mm Hg ( 4.1–11.2/2.7–7.7 , P<0.001 for both ) . Home BP was reduced by 8.1/3.8 mm Hg ( 3.8–12.4/0.7–6.9 , P<0.001 and P<0.01 ) with no evidence of tachyphylaxis over the 4-week intervention period . Endothelial function improved by ≈20 % ( P<0.001 ) , and arterial stiffness was reduced by 0.59 m/s ( 0.24–0.93 ; P<0.01 ) after dietary nitrate consumption with no change after placebo . The intervention was well tolerated . This is the first evidence of durable BP reduction  with dietary nitrate supplementation in a relevant patient group . These findings suggest a role for dietary nitrate as an affordable , readily-available , adjunctive treatment in the management of patients with hypertension ( funded by The British Heart Foundation ) . Clinical Trial Registration —URL : http://www . clinical trials.gov . Unique identifier : NCT01405898 A number of vegetables have a high nitrate content which after ingestion can be reduced to nitrite by oral bacteria , and further to vasoprotective NO endogenously . In the present study , two separate r and omly controlled , single-blind , cross-over , postpr and ial studies were performed in normotensive volunteers . Ambulatory blood pressure ( BP ) was measured over a 24 h period following consumption of either four doses of beetroot juice ( BJ ) , 0 , 100 , 250 and 500 g ( n 18 ) , or three bread products , control bread ( 0 g beetroot ) , red beetroot- and white beetroot-enriched breads ( n 14 ) . Total urinary nitrate/nitrite ( NO(x ) ) was measured at baseline , and at 2 , 4 and 24 h post-ingestion . BJ consumption significantly , and in a near dose-dependent manner , lowered systolic BP ( SBP , P < 0·01 ) and diastolic BP ( DBP , P < 0·001 ) over a period of 24 h , compared with water control . Furthermore , bread products enriched with 100 g red or white beetroot lowered SBP and DBP over a period of 24 h ( red beetroot-enriched bread , P < 0·05 ) , with no statistical differences between the varieties . Total urinary NO(x ) significantly increased following the consumption of 100 g ( P < 0·01 ) , 250 g ( P < 0·001 ) and 500 g BJ ( P < 0·001 ) and after red beetroot-enriched bread ingestion ( P < 0·05 ) , but did not reach significance for white beetroot-enriched bread compared with the no-beetroot condition . These studies demonstrated significant hypotensive effects of a low dose ( 100 g ) of beetroot which was unaffected by processing or the presence of betacyanins . These data strengthen the evidence for cardioprotective BP-lowering effects of dietary nitrate-rich vegetables Evidence for a beneficial effect of dietary nitrate , through the nitrate-nitrite-NO pathway , on measures of cardiovascular function in healthy individuals is accumulating . It is less clear whether increased dietary nitrate intake from green leafy vegetables would have similar beneficial vascular effects in those at increased risk of developing hypertension . Our aim was to assess the effects of short-term regular consumption of increased nitrate from green leafy vegetables on blood pressure and arterial stiffness in individuals with high-normal blood pressure . Thirty-eight men and women ages 30 - 70 years with systolic blood pressure 120 to 139 mm Hg were recruited to a r and omized controlled crossover trial . The effects of a 7-day high-nitrate diet intervention ( increased nitrate intake by at least 300 mg/day from green leafy vegetables ) were compared to a 7-day low-nitrate diet intervention . Outcome measures included pre- and postintervention salivary and plasma nitrate and nitrite concentrations ; ambulatory , home , and office blood pressure ; augmentation index ; and carotid-femoral pulse wave velocity . The high-nitrate diet intervention result ed in at least a fourfold increase in salivary and plasma nitrate and nitrite ( P<0.001 ) . Ambulatory , home , and office blood pressure and arterial stiffness were not different between the high-nitrate diet and the low-nitrate diet . Increasing dietary nitrate intake in those with high-normal blood pressure and at increased risk of hypertension may not be an effective short-term strategy to lower blood pressure OBJECTIVE Epidemiological studies suggest that green leafy vegetables , which are high in dietary nitrate , are protective against CVD such as stroke . High blood pressure ( BP ) is a major risk factor for stroke and inorganic nitrate has been shown to reduce BP . The objective of the present study was to test the hypothesis that diets containing high-nitrate ( HN ) vegetables would increase plasma nitrate and nitrite concentrations and reduce BP in healthy women . DESIGN A r and omized , crossover trial , where participants received HN vegetables ( HN diet ) or avoided HN vegetables ( Control diet ) for 1 week . Before and after each intervention , resting BP and plasma nitrate and nitrite concentrations were measured . SETTING University of Exeter , UK . SUBJECTS Nineteen healthy women ( mean age 20 ( sd 2 ) years ; mean BMI 22·5 ( sd 3·8 ) kg/m2 ) . RESULTS The HN diet significantly increased plasma nitrate concentration ( before HN diet : mean 24·4 ( sd 5·6 ) µmol/l ; after HN diet : mean 61·0 ( sd 44·1 ) µmol/l , P<0·05 ) and plasma nitrite concentration ( before HN diet : mean 98 ( sd 91 ) nmol/l ; after HN diet : mean 185 ( sd 34 ) nmol/l , P<0·05 ) . No significant change in plasma nitrate or nitrite concentration was observed after the Control diet . The HN diet significantly reduced resting systolic BP ( before HN diet : mean 107 ( sd 9 ) mmHg ; after HN diet : mean 103 ( sd 6 ) mmHg , P<0·05 ) . No significant change in systolic BP was observed after the Control diet ( before Control diet : mean 106 ( sd 8) mmHg ; after Control diet : mean 106 ( sd 8) mmHg ) . CONCLUSIONS Consumption of HN vegetables  significantly increased plasma nitrate and nitrite concentrations and reduced BP in normotensive women Although inorganic nitrate and beetroot juice supplementation are associated with decreased systolic blood pressure ( BP ) , these results have primarily been obtained from short-term trials that focused on healthy young adults . Therefore , we hypothesized that oral supplementation of beetroot juice concentrate would decrease systolic BP in overweight older participants but that the decline in BP would not be sustained after a 1-week interruption of the beetroot juice supplementation . For 3 weeks , 24 participants were r and omized to either the beetroot juice concentrate or blackcurrant juice group , with a 1-week postsupplementation phase ( week 4 ) . Changes in systolic and diastolic BP were assessed during the supplementation and postsupplementation phases . Blood pressure was measured using 3 different methods : ( 1 ) resting clinic BP , ( 2 ) 24-hour ambulatory BP monitoring , and ( 3 ) home monitoring of daily resting BP . The first 2 methods were applied at baseline and after weeks 3 and 4 . Daily measurements were conducted throughout the study , with 21 subjects completing the study ( beetroot/blackcurrant = 10/11 ; male/female = 12/9 ; age = 62.0 ± 1.4 years ; body mass index = 30.1 ± 1.2 kg/m(2 ) ) . After 3 weeks , beetroot juice supplementation was not associated with significant changes in resting clinic BP or 24-hour ABPM .  Conversely , beetroot juice concentrate  reduced daily systolic BP after 3 weeks ( -7.3 ± 5.9 mm Hg , P = .02 ) ; however , the effect was not maintained after the interruption of the supplementation ( week 4 , 2.8 ± 6.1 mm Hg , P = .09 ) . In overweight older subjects , beetroot juice concentrate supplementation was associated with beneficial effects on daily systolic BP , although the effects were not significant when measured by 24-hour ABPM or resting clinic BP Background The consumption of beetroot juice on a low nitrate diet may lower blood pressure ( BP ) and therefore reduce the risk of cardiovascular events . However , it is unknown if its inclusion as part of a normal diet has a similar effect on BP . The aim of the study was to conduct a r and omized controlled trial with free-living adults to investigate if consuming beetroot juice in addition to a normal diet produces a measureable reduction in BP . Method Fifteen women and fifteen men participated in a double-blind , r and omized , placebo-controlled , crossover study . Volunteers were r and omized to receive 500 g of beetroot and apple juice ( BJ ) or a placebo juice ( PL ) . Volunteers had BP measured at baseline and at least hourly for 24-h following juice consumption using an ambulatory blood pressure monitor ( ABPM ) . Volunteers remained at the clinic for 1-h before resuming normal non-strenuous daily activities . The identical procedure was repeated 2-wk later with the drink ( BJ or PL ) not consumed on the first visit . Results Overall , there was a trend ( P=0.064 ) to lower systolic blood pressure ( SBP ) at 6-h after drinking BJ relative to PL . Analysis in men only ( n=13 ) after adjustment for baseline differences demonstrated a significant ( P<0.05 ) reduction in SBP of 4 – 5 mmHg at 6-h after drinking BJ . Conclusions Beetroot juice will lower BP in men when consumed as part of a normal diet in free-living healthy adults . Trial registration anzctr.org.au Flavonoids and nitrates in fruits and vegetables may protect against cardiovascular disease . Dietary flavonoids and nitrates can augment nitric oxide status via distinct pathways , which may improve endothelial function and lower blood pressure . Recent studies suggest that the combination of flavonoids and nitrates can enhance nitric oxide production in the stomach . Their combined effect in the circulation is unclear . Here , our objective was to investigate the independent and additive effects of flavonoid-rich apples and nitrate-rich spinach on nitric oxide status , endothelial function , and blood pressure . A r and omized , controlled , crossover trial with healthy men and women ( n=30 ) was conducted . The acute effects of four energy-matched treatments ( control , apple , spinach , and apple+spinach ) , administered in r and om order , were compared . Measurements included plasma nitric oxide status , assessed by measuring S-nitrosothiols+other nitrosylated species ( RXNO ) and nitrite , blood pressure , and endothelial function , measured as flow-mediated dilatation of the brachial artery . Results are means and 95 % CI . Relative to control , all treatments result ed in higher RXNO ( control , 33 nmol/L , 26 , 42 ; apple , 51 nmol/L , 40 , 65 ; spinach , 86 nmol/L , 68 , 110 ; apple+spinach , 69 nmol/L , 54 , 88 ; P<0.01 ) and higher nitrite ( control , 35 nmol/L , 27 , 46 ; apple , 69 nmol/L , 53 , 90 ; spinach , 99 nmol/L , 76 , 129 ; apple 
    Output:
    
Conclusions Inorganic nitrate consumption represents a simple strategy for targeting cardiovascular disease risk factors .