***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: 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 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 Use of the DASH ( Dietary Approaches to Stop Hypertension ) diet , which is rich in fruits , vegetables , and low-fat dairy foods , significantly lowers blood pressure .  Among the 459 participants in the DASH Trial , 72 had stage 1 isolated systolic hypertension ( ISH ) ( systolic blood pressure , 140 to 159 mm Hg ; diastolic blood pressure , < 90 mm Hg ) . We examined the blood pressure response in these 72 participants to determine whether the DASH diet is an effective treatment for stage 1 ISH . After a 3-week run-in period on a typical American ( control ) diet , participants were r and omly assigned for 8 weeks to 1 of 3 diets : a continuation of the control diet ( n=25 ) , a diet rich in fruits and vegetables ( n=24 ) , or the DASH diet ( n=23 ) . Sodium content was the same in the 3 diets , and caloric intake was adjusted during the trial to prevent weight change . Blood pressure was measured at baseline and at the end of the 8-week intervention period with st and ard sphygmomanometry . Use of the DASH diet significantly lowered systolic blood pressure compared with the control diet ( −11.2 mm Hg ; 95 % confidence interval , −6.1 to −16.2 mm Hg;P < 0.001 ) and the fruits/vegetables diet ( −8.0 mm Hg ; 95 % confidence interval , −2.5 to −13.4 mm Hg;P < 0.01 ) . Overall , blood pressure in the DASH group fell from 146/85 to 134/82 mm Hg . Similar results were observed with 24-hour ambulatory blood pressure measurements . In the DASH diet group , 18 of 23 participants ( 78 % ) reduced their systolic blood pressure to < 140 mm Hg , compared with 24 % and 50 % in the control and fruits/vegetables groups , respectively . Our results indicate that the DASH diet , which is rich in fruits , vegetables , and low-fat dairy foods , is effective as first-line therapy in stage 1 ISH The mechanism underlying blood pressure ( BP ) reduction in the high fruits and vegetables arm of the Dietary Approaches to Stop Hypertension ( DASH ) study is unknown but may include potassium , magnesium and fibre . This study was design ed to separate minerals and fibre from other components of DASH on BP in abdominally obese individuals with metabolic syndrome with pre-hypertension to stage 1 hypertension ( obese hypertensives ) . A total of 15 obese hypertensives and 15 lean normotensives were studied on a st and ardized usual diet , r and omized to DASH or usual diet supplemented with potassium , magnesium and fibre to match DASH , then crossed over to the complementary diet . All diets were 3 weeks long , isocaloric and matched for sodium and calcium . In obese hypertensives , BP was lower after 3 weeks on DASH than usual diet ( −7.6±1.4/−5.3±1.4 mm Hg , P<0.001/0.02 ) and usual diet supplemented ( −6.2±1.4/−3.7±1.4 P<0.005/0.06 ) , whereas BP was not significantly different on usual and supplemented diets . BP values were not different among the three diets in lean normotensives . Small artery elasticity was lower in obese hypertensives than in lean normotensives on the usual and supplemented diets ( P<0.02 ) . This index of endothelial function improved in obese hypertensives ( P<0.02 ) but not lean normotensives on DASH , and was no longer different from values in lean normotensives ( P>0.50 ) . DASH is more effective than potassium , magnesium and fibre supplements for lowering BP in obese hypertensives , which suggest that high fruits and vegetables DASH  lowers BP and improves endothelial function in this group by nutritional factors in addition to potassium , magnesium and fibre Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more The anion nitrate-abundant in our diet-has recently emerged as a major pool of nitric oxide ( NO ) synthase-independent NO production . Nitrate is reduced stepwise in vivo to nitrite and then NO and possibly other bioactive nitrogen oxides . This reductive pathway is enhanced during low oxygen tension and acidosis . A recent study shows a reduction in oxygen consumption during submaximal exercise attributable to dietary nitrate . We went on to study the effects of dietary nitrate on various physiological and biochemical parameters during maximal exercise . Nine healthy , nonsmoking volunteers ( age 30+/-2.3 years , VO(2max ) 3.72+/-0.33 L/min ) participated in this study , which had a r and omized , double-blind crossover design . Subjects received dietary supplementation with sodium nitrate ( 0.1 mmol/kg/day ) or placebo ( NaCl ) for 2 days before the test . This dose corresponds to the amount found in 100 - 300 g of a nitrate-rich vegetable such as spinach or beetroot . The maximal exercise tests consisted of an incremental exercise to exhaustion with combined arm and leg cranking on two separate ergometers . Dietary nitrate reduced VO(2max ) from 3.72+/-0.33 to 3.62+/-0.31 L/min , P<0.05 . Despite the reduction in VO(2max ) the time to exhaustion trended to an increase after nitrate supplementation ( 524+/-31 vs 563+/-30 s , P=0.13 ) . There was a correlation between the change in time to exhaustion and the change in VO(2max ) ( R(2)=0.47 , P=0.04 ) . A moderate dietary dose of nitrate significantly reduces VO(2max ) during maximal exercise using a large active muscle mass . This reduction occurred with a trend toward increased time to exhaustion implying that two separate mechanisms are involved : one that reduces VO(2max ) and another that improves the energetic function of the working muscles Six days of dietary nitrate supplementation in the form of beetroot juice ( ~0.5 L/d ) has been reported to reduce pulmonary oxygen uptake ( VO₂ ) during submaximal exercise and increase tolerance of high-intensity work rates , suggesting that nitrate can be a potent ergogenic aid . Limited data are available regarding the effect of nitrate ingestion on athletic performance , and no study has investigated the potential ergogenic effects of a small-volume , concentrated dose of beetroot juice . The authors tested the hypothesis that 6 d of nitrate ingestion would improve time-trial performance in trained cyclists . Using a double-blind , repeated- measures crossover design , 12 male cyclists ( 31±3 yr , VO2peak=58±2 ml·kg⁻¹·min⁻¹ , maximal power [Wmax]=342±10 W ) ingested 140 ml/d of concentrated beetroot ( ~8 mmol/d nitrate ) juice ( BEET ) or a placebo ( nitrate-depleted beetroot juice ; PLAC ) for 6 d , separated by a 14-d washout . After supplementation on Day 6 , subjects performed 60 min of submaximal cycling ( 2 × 30 min at 45 % and 65 % Wmax , respectively ) , followed by a 10-km time trial . Time-trial performance ( 953±18 vs. 965±18 s , p<.005 ) and power output ( 294±12 vs. 288±12 W , p<.05 ) improved after BEET compared with PLAC supplementation . Submaximal VO₂ was lower after BEET ( 45 % Wmax=1.92±0.06 vs. 2.02±0.09 L/min , 65 % Wmax 2.94±0.12 vs. 3.11±0.12 L/min ) than with PLAC ( main effect , p<.05 ) . Whole-body fuel selection and plasma lactate , glucose , and insulin concentrations did not differ between treatments . Six days of nitrate supplementation reduced VO₂ during submaximal exercise and improved time-trial performance in trained cyclists PURPOSE Dietary nitrate supplementation has been shown to reduce the O2 cost of submaximal exercise and to improve high-intensity exercise tolerance . However , it is presently unknown whether it may enhance performance during simulated competition . The present study investigated the effects of acute dietary nitrate supplementation on power output ( PO ) , VO2 , and performance during 4- and 16.1-km cycling time trials ( TT ) . METHODS After familiarization , nine club-level competitive male cyclists were assigned in a r and omized , crossover design to consume 0.5 L of beetroot juice ( BR ; containing ∼ 6.2 mmol of nitrate ) or 0.5 L of nitrate-depleted BR ( placebo , PL ; containing ∼ 0.0047 mmol of nitrate ) , ∼ 2.5 h before the completion of a 4- and a 16.1-km TT . RESULTS BR supplementation elevated plasma [ nitrite ] ( PL = 241 ± 125 vs BR = 575 ± 199 nM , P < 0.05 ) . The VO2 values during the TT were not significantly different between the BR and PL conditions at any elapsed distance ( P > 0.05 ) , but BR significantly increased mean PO during the 4-km ( PL = 279 ± 5 
    Output:
    
Inorganic nitrate and beetroot juice supplementation was associated with a significant reduction in systolic BP .