Effects of inorganic nitrate and vitamin C co-supplementation on blood pressure and vascular function in younger and older healthy adults: A randomised double-blind crossover trial

Ammar W Ashor, Oliver M Shannon, Anke-Dorothee Werner, Filippo Scialo, Cameron N Gilliard, Katelyn S Cassel, Chris J Seal, D. Zheng, John C Mathers, Mario Siervo

Research output: Contribution to journalArticle

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Abstract

Background
Vitamin C and inorganic nitrate have been linked to enhanced nitric oxide (NO) production and reduced oxidative stress. Vitamin C may also enhance the conversion of nitrite into NO.

Aims
We investigated the potential acute effects of vitamin C and inorganic nitrate co-supplementation on blood pressure (BP) and peripheral vascular function. The secondary aim was to investigate whether age modified the effects of vitamin C and inorganic nitrate on these vascular outcomes.

Methods
Ten younger (age 18–40 y) and ten older (age 55–70 y) healthy participants were enrolled in a randomised double-blind crossover clinical trial. Participants ingested a solution of potassium nitrate (7 mg/kg body weight) and/or vitamin C (20 mg/kg body weight) or their placebos. Acute changes in resting BP and vascular function (post-occlusion reactive hyperemia [PORH], peripheral pulse wave velocity [PWV]) were monitored over a 3-h period.

Results
Vitamin C supplementation reduced PWV significantly (vitamin C: −0.70 ± 0.31 m/s; vitamin C placebo: +0.43 ± 0.30 m/s; P = 0.007). There were significant interactions between age and vitamin C for systolic, diastolic, and mean arterial BP (P = 0.02, P = 0.03, P = 0.02, respectively), with systolic, diastolic and mean BP decreasing in older participants and diastolic BP increasing in younger participants following vitamin C administration. Nitrate supplementation did not influence BP (systolic: P = 0.81; diastolic: P = 0.24; mean BP: P = 0.87) or vascular function (PORH: P = 0.05; PWV: P = 0.44) significantly in both younger and older participants. However, combined supplementation with nitrate and vitamin C reduced mean arterial BP (−2.6 mmHg, P = 0.03) and decreased PWV in older participants (PWV: −2.0 m/s, P = 0.02).

Conclusions
The co-administration of a single dose of inorganic nitrate and vitamin C lowered diastolic BP and improved PVW in older participants. Vitamin C supplementation improved PWV in both age groups but decreased systolic and mean BP in older participants only.

Clinical trial registration
Current Controlled Trials (ISRCTN98942199).
Original languageEnglish
Pages (from-to)(In-Press)
JournalClinical Nutrition
Volume(In-Press)
Early online date20 Mar 2019
DOIs
Publication statusE-pub ahead of print - 20 Mar 2019
Externally publishedYes

Fingerprint

Nitrates
Cross-Over Studies
Ascorbic Acid
Blood Vessels
Blood Pressure
Pulse Wave Analysis
Arterial Pressure
Hyperemia
Nitric Oxide
Placebos
Body Weight
Controlled Clinical Trials
Nitrites
Healthy Volunteers
Oxidative Stress
Age Groups
Clinical Trials

Keywords

  • Dietary nitrate
  • Ascorbic acid
  • Aging
  • Blood pressure
  • Vascular function
  • Arterial stiffness

Cite this

Effects of inorganic nitrate and vitamin C co-supplementation on blood pressure and vascular function in younger and older healthy adults: A randomised double-blind crossover trial. / Ashor, Ammar W; Shannon, Oliver M; Werner, Anke-Dorothee; Scialo, Filippo; Gilliard, Cameron N; Cassel, Katelyn S; Seal, Chris J; Zheng, D.; Mathers, John C; Siervo, Mario.

In: Clinical Nutrition, Vol. (In-Press), 20.03.2019, p. (In-Press).

Research output: Contribution to journalArticle

Ashor, Ammar W ; Shannon, Oliver M ; Werner, Anke-Dorothee ; Scialo, Filippo ; Gilliard, Cameron N ; Cassel, Katelyn S ; Seal, Chris J ; Zheng, D. ; Mathers, John C ; Siervo, Mario. / Effects of inorganic nitrate and vitamin C co-supplementation on blood pressure and vascular function in younger and older healthy adults: A randomised double-blind crossover trial. In: Clinical Nutrition. 2019 ; Vol. (In-Press). pp. (In-Press).
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abstract = "BackgroundVitamin C and inorganic nitrate have been linked to enhanced nitric oxide (NO) production and reduced oxidative stress. Vitamin C may also enhance the conversion of nitrite into NO.AimsWe investigated the potential acute effects of vitamin C and inorganic nitrate co-supplementation on blood pressure (BP) and peripheral vascular function. The secondary aim was to investigate whether age modified the effects of vitamin C and inorganic nitrate on these vascular outcomes.MethodsTen younger (age 18–40 y) and ten older (age 55–70 y) healthy participants were enrolled in a randomised double-blind crossover clinical trial. Participants ingested a solution of potassium nitrate (7 mg/kg body weight) and/or vitamin C (20 mg/kg body weight) or their placebos. Acute changes in resting BP and vascular function (post-occlusion reactive hyperemia [PORH], peripheral pulse wave velocity [PWV]) were monitored over a 3-h period.ResultsVitamin C supplementation reduced PWV significantly (vitamin C: −0.70 ± 0.31 m/s; vitamin C placebo: +0.43 ± 0.30 m/s; P = 0.007). There were significant interactions between age and vitamin C for systolic, diastolic, and mean arterial BP (P = 0.02, P = 0.03, P = 0.02, respectively), with systolic, diastolic and mean BP decreasing in older participants and diastolic BP increasing in younger participants following vitamin C administration. Nitrate supplementation did not influence BP (systolic: P = 0.81; diastolic: P = 0.24; mean BP: P = 0.87) or vascular function (PORH: P = 0.05; PWV: P = 0.44) significantly in both younger and older participants. However, combined supplementation with nitrate and vitamin C reduced mean arterial BP (−2.6 mmHg, P = 0.03) and decreased PWV in older participants (PWV: −2.0 m/s, P = 0.02).ConclusionsThe co-administration of a single dose of inorganic nitrate and vitamin C lowered diastolic BP and improved PVW in older participants. Vitamin C supplementation improved PWV in both age groups but decreased systolic and mean BP in older participants only.Clinical trial registrationCurrent Controlled Trials (ISRCTN98942199).",
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author = "Ashor, {Ammar W} and Shannon, {Oliver M} and Anke-Dorothee Werner and Filippo Scialo and Gilliard, {Cameron N} and Cassel, {Katelyn S} and Seal, {Chris J} and D. Zheng and Mathers, {John C} and Mario Siervo",
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T1 - Effects of inorganic nitrate and vitamin C co-supplementation on blood pressure and vascular function in younger and older healthy adults: A randomised double-blind crossover trial

AU - Ashor, Ammar W

AU - Shannon, Oliver M

AU - Werner, Anke-Dorothee

AU - Scialo, Filippo

AU - Gilliard, Cameron N

AU - Cassel, Katelyn S

AU - Seal, Chris J

AU - Zheng, D.

AU - Mathers, John C

AU - Siervo, Mario

PY - 2019/3/20

Y1 - 2019/3/20

N2 - BackgroundVitamin C and inorganic nitrate have been linked to enhanced nitric oxide (NO) production and reduced oxidative stress. Vitamin C may also enhance the conversion of nitrite into NO.AimsWe investigated the potential acute effects of vitamin C and inorganic nitrate co-supplementation on blood pressure (BP) and peripheral vascular function. The secondary aim was to investigate whether age modified the effects of vitamin C and inorganic nitrate on these vascular outcomes.MethodsTen younger (age 18–40 y) and ten older (age 55–70 y) healthy participants were enrolled in a randomised double-blind crossover clinical trial. Participants ingested a solution of potassium nitrate (7 mg/kg body weight) and/or vitamin C (20 mg/kg body weight) or their placebos. Acute changes in resting BP and vascular function (post-occlusion reactive hyperemia [PORH], peripheral pulse wave velocity [PWV]) were monitored over a 3-h period.ResultsVitamin C supplementation reduced PWV significantly (vitamin C: −0.70 ± 0.31 m/s; vitamin C placebo: +0.43 ± 0.30 m/s; P = 0.007). There were significant interactions between age and vitamin C for systolic, diastolic, and mean arterial BP (P = 0.02, P = 0.03, P = 0.02, respectively), with systolic, diastolic and mean BP decreasing in older participants and diastolic BP increasing in younger participants following vitamin C administration. Nitrate supplementation did not influence BP (systolic: P = 0.81; diastolic: P = 0.24; mean BP: P = 0.87) or vascular function (PORH: P = 0.05; PWV: P = 0.44) significantly in both younger and older participants. However, combined supplementation with nitrate and vitamin C reduced mean arterial BP (−2.6 mmHg, P = 0.03) and decreased PWV in older participants (PWV: −2.0 m/s, P = 0.02).ConclusionsThe co-administration of a single dose of inorganic nitrate and vitamin C lowered diastolic BP and improved PVW in older participants. Vitamin C supplementation improved PWV in both age groups but decreased systolic and mean BP in older participants only.Clinical trial registrationCurrent Controlled Trials (ISRCTN98942199).

AB - BackgroundVitamin C and inorganic nitrate have been linked to enhanced nitric oxide (NO) production and reduced oxidative stress. Vitamin C may also enhance the conversion of nitrite into NO.AimsWe investigated the potential acute effects of vitamin C and inorganic nitrate co-supplementation on blood pressure (BP) and peripheral vascular function. The secondary aim was to investigate whether age modified the effects of vitamin C and inorganic nitrate on these vascular outcomes.MethodsTen younger (age 18–40 y) and ten older (age 55–70 y) healthy participants were enrolled in a randomised double-blind crossover clinical trial. Participants ingested a solution of potassium nitrate (7 mg/kg body weight) and/or vitamin C (20 mg/kg body weight) or their placebos. Acute changes in resting BP and vascular function (post-occlusion reactive hyperemia [PORH], peripheral pulse wave velocity [PWV]) were monitored over a 3-h period.ResultsVitamin C supplementation reduced PWV significantly (vitamin C: −0.70 ± 0.31 m/s; vitamin C placebo: +0.43 ± 0.30 m/s; P = 0.007). There were significant interactions between age and vitamin C for systolic, diastolic, and mean arterial BP (P = 0.02, P = 0.03, P = 0.02, respectively), with systolic, diastolic and mean BP decreasing in older participants and diastolic BP increasing in younger participants following vitamin C administration. Nitrate supplementation did not influence BP (systolic: P = 0.81; diastolic: P = 0.24; mean BP: P = 0.87) or vascular function (PORH: P = 0.05; PWV: P = 0.44) significantly in both younger and older participants. However, combined supplementation with nitrate and vitamin C reduced mean arterial BP (−2.6 mmHg, P = 0.03) and decreased PWV in older participants (PWV: −2.0 m/s, P = 0.02).ConclusionsThe co-administration of a single dose of inorganic nitrate and vitamin C lowered diastolic BP and improved PVW in older participants. Vitamin C supplementation improved PWV in both age groups but decreased systolic and mean BP in older participants only.Clinical trial registrationCurrent Controlled Trials (ISRCTN98942199).

KW - Dietary nitrate

KW - Ascorbic acid

KW - Aging

KW - Blood pressure

KW - Vascular function

KW - Arterial stiffness

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DO - 10.1016/j.clnu.2019.03.006

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