***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 Beetroot has a high concentration of inorganic nitrate , which can serially reduced to form nitrite and nitric oxide ( NO ) after oral ingestion . Increased renal resistive index ( RRI ) measured by Doppler ultrasonography is associated with higher cardiovascular mortality in hypertensive patients with reduced renal function over time defined as chronic kidney disease ( CKD ) . Our aim was to investigate whether the supplementation of dietary nitrate by administration of beetroot juice is able to reduce blood pressure and renal resistive index ( RRI ) as prognostic markers for cardiovascular mortality in CKD patients . In a cross-over study design , 17 CKD patients were r and omized to either a dietary nitrate load ( 300 mg ) by highly concentrated beetroot juice ( BJ ) or placebo ( water ) . Hemodynamic parameters as well as plasma nitrate concentration and RRI were measured before and 4 h after treatment . In this cohort , CKD was mainly caused by hypertensive or diabetic nephropathy . The mean eGFR was 41.6 ± 12.0 ml/min/m2  . Plasma nitrate concentrations were significantly increased after ingestion of BJ compared to control . Peripheral systolic and diastolic blood pressure as well as mean arterial pressure ( MAP ) were significantly reduced secondary to the dietary nitrate load compared to control ( e.g. ΔMAPBJ = -8.2 ± 7.6 mmHg vs. ΔMAPcontrol = -2.2 ± 6.0 mmHg , p = 0.012 ) . BJ also led to significantly reduced RRI values ( ΔRRIBJ = -0.03 ± 0.04 versus ΔRRIcontrol = 0.01 ± 0.04 ; p = 0.017 ) . Serum potassium levels were not altered secondary to the treatment . In this study , administration of the nitrate donor BJ led to significantly reduced RRI values and peripheral blood pressure which might be explained by release of the vasodilatator NO after oral intake . Whether supplementation of dietary nitrate in addition to routine pharmacologic therapy is able to decelerate progression of cardiovascular and renal disease in CKD , remains to be investigated 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 ± 51 vs BR = 292 ± 44 W , P < 0.05 ) and 16.1-km TT ( PL = 233 ± 43 vs BR = 247 ± 44 W , P < 0.01 ) . Consequently , BR improved 4-km performance by 2.8 % ( PL = 6.45 ± 0.42 vs BR = 6.27 ± 0.35 min , P < 0.05 ) and 16.1-km performance by 2.7 % ( PL = 27.7 ± 2.1 vs BR = 26.9 ± 1.8 min , P < 0.01 ) . CONCLUSIONS These results suggest that acute dietary nitrate supplementation with 0.5 L of BR improves cycling economy , as demonstrated by a higher PO for the same VO2 and enhances both 4- and 16.1-km cycling TT performance Circulating nitrate ( NO3− ) , derived from dietary sources or endogenous nitric oxide production , is extracted from blood by the salivary gl and s , accumulates in saliva , and is then reduced to nitrite ( NO2− ) by the oral microflora . This process has historically been viewed as harmful , because nitrite can promote formation of potentially carcinogenic N-nitrosamines . More recent research , however , suggests that nitrite can also serve as a precursor for systemic generation of vasodilatory nitric oxide , and exogenous administration of nitrate reduces blood pressure in humans . However , whether oral nitrate-reducing bacteria participate in “ setting ” blood pressure is unknown . We investigated whether suppression of the oral microflora affects systemic nitrite levels and hence blood pressure in healthy individuals . We measured blood pressure ( clinic , home , and 24-h ambulatory ) in 19 healthy volunteers during an initial 7-day control period followed by a 7-day treatment period with a chlorhexidine-based antiseptic mouthwash . Oral nitrate-reducing capacity and nitrite levels were measured after each study period . Antiseptic mouthwash treatment reduced oral nitrite production by 90 % ( p < 0.001 ) and plasma nitrite levels by 25 % ( p = 0.001 ) compared to the control period . Systolic and diastolic blood pressure increased by 2–3 .5 mm Hg , increases correlated to a decrease in circulating nitrite concentrations ( r2 = 0.56 , p = 0.002 ) . The blood pressure effect appeared within 1 day of disruption of the oral microflora and was sustained during the 7-day mouthwash intervention . These results suggest that the recycling of endogenous nitrate by oral bacteria plays an important role in determination of plasma nitrite levels and thereby in the physiological control of blood pressure Nitric oxide ( NO ) synthase inhibition reduces leg glucose uptake during cycling without reducing leg blood flow ( LBF ) in young , healthy individuals . This study sought to determine the role of NO in glucose uptake during exercise in individuals with type 2 diabetes . Nine men with type 2 diabetes and nine control subjects matched for age , sex , peak pulmonary oxygen uptake ( VO(2 ) peak ) , and weight completed two 25-min bouts of cycling exercise at 60 + /- 2 % VO(2 ) peak , separated by 90 min . N(G)-monomethyl-L-arginine ( L-NMMA ) ( total dose 6 mg/kg ) or placebo was administered into the femoral artery for the final 15 min of exercise in a counterbalanced , blinded , crossover design . LBF was measured by thermodilution in the femoral vein , and leg glucose uptake was calculated as the product of LBF and femoral arteriovenous glucose difference . During exercise with placebo , glucose uptake was not different between control subjects and individuals with diabetes ; however , LBF was lower and arterial plasma glucose and insulin levels were higher in individuals with diabetes . L-NMMA had no effect on LBF or arterial plasma glucose and insulin concentrations during exercise in both groups . L-NMMA significantly reduced leg glucose uptake in both groups , with a significantly greater reduction ( P = 0.04 ) in the diabetic group ( 75 + /- 13 % , 5 min after L-NMMA ) compared with the control group ( 34 + /- 14 % , 5 min after L-NMMA ) . These data suggest a greater reliance on NO for glucose uptake during exercise in individuals with type 2 diabetes compared with control subjects Diets rich in green , leafy vegetables have been shown to lower blood pressure ( BP ) and reduce the risk of cardiovascular disease .  Green , leafy vegetables and beetroot are particularly rich in inorganic nitrate . Dietary nitrate supplementation , via sequential reduction to nitrite and NO , has previously been shown to lower BP and improve endothelial function in healthy humans . We sought to determine if supplementing dietary nitrate with beetroot juice , a rich source of nitrate , will lower BP and improve endothelial function and insulin sensitivity in individuals with type 2 diabetes ( T2DM ) . Twenty-seven patients , age 67.2±4.9 years ( 18 male ) , were recruited for a double-blind , r and omized , placebo-controlled crossover trial . Participants were r and omized to begin , in either order , a 2-week period of supplementation with 250ml beetroot juice daily ( active ) or 250ml nitrate-depleted beetroot juice ( placebo ) . At the conclusion of each intervention period 24-h ambulatory blood pressure monitoring , tests of macro- and microvascular endothelial function , and a hyperinsulinemic isoglycemic clamp were performed . After 2 weeks administration of beetroot juice mean ambulatory systolic BP was unchanged : 134.6±8.4mmHg versus 135.1±7.8mmHg ( mean±SD ) , placebo vs active-mean difference of -0.5mmHg ( placebo-active ) , p=0.737 ( 95 % CI -3.9 to 2.8 ) . There were no changes in macrovascular or microvascular endothelial function or insulin sensitivity . Supplementation of the diet with 7.5mmol of nitrate per day for 2 weeks caused an increase in plasma nitrite and nitrate concentration , but did not lower BP , improve endothelial function , or improve insulin sensitivity in individuals with T2DM Although dietary nitrate ( NO3- ) ingestion appears to enhance exercise capacity and performance in young individuals , inconclusive findings have been reported in older people . Therefore , we conducted a double-blind , crossover r and omized clinical trial using beetroot juice in older healthy participants , who were classified as normal weight and overweight . We tested whether consumption of beetroot juice ( a rich source of NO3- ) for 1 week would increase nitric oxide bioavailability via the nonenzymatic pathway and enhance ( 1 ) exercise capacity during an incremental exercise test , ( 2 ) physical capability , and ( 3 ) free-living physical activity .  Twenty nonsmoking , healthy participants between 60 and 75 years of age and with a body mass index of 20.0 to 29.9 kg/m2 were included . Presupplementation and postsupplementation resting , submaximal , maximal , and recovery gas exchanges were measured . Physical capability was measured by h and -grip strength , time-up- and -go , repeated chair rising test , and 
    Output:
    
The current literature indicates positive effects of dietary NO3− supplementation in older adults on physiological performance , with some evidence indicating benefits on cardiovascular and cerebrovascular health .
Effects on cognitive performance were mixed and studies on metabolic health indicated no benefit .