Trial Outcomes & Findings for Inorganic Nitrate Supplementation on Cerebrovascular Aging and Arterial Stiffness Study (NCT NCT03617302)

Last Updated: 2026-03-04

Results Overview

Common carotid artery compliance measured by ultrasonography and applanation tonometry. Carotid compliance is the change in carotid diameter per change in carotid pulse pressure.

Recruitment status

COMPLETED

Study phase

EARLY_PHASE1

Target enrollment

16 participants

Primary outcome timeframe

Baseline and 2 hours following nitrate-depleted placebo beetroot juice or nitrate-containing beetroot juice

Results posted on

2026-03-04

Participant Flow

Participants were randomly assigned to receive beetroot juice or placebo on visit one and then crossed-over to receive the other treatment on visit 2.

Participant milestones

Participant milestones
Measure	Beetroot Juice First, Then Placebo Beetroot Juice 10-grams of nitrate-containing beetroot concentrate diluted in 120-180 milliliters of water or placebo	Placebo Beetroot Juice, Then Beetroot Juice Placebo or 10-grams of nitrate-containing beetroot concentrate diluted in 120-180 milliliters of water
First Intervention 2 Hrs, Washout 3 Hrs STARTED	8	8
First Intervention 2 Hrs, Washout 3 Hrs COMPLETED	8	8
First Intervention 2 Hrs, Washout 3 Hrs NOT COMPLETED	0	0
2nd Intervention 2 Hrs, Washout 3 Hrs STARTED	8	8
2nd Intervention 2 Hrs, Washout 3 Hrs COMPLETED	8	8
2nd Intervention 2 Hrs, Washout 3 Hrs NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Inorganic Nitrate Supplementation on Cerebrovascular Aging and Arterial Stiffness Study

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	All Study Participants n=16 Participants 10-grams of nitrate-containing beetroot concentrate diluted in 120-180 milliliters of water. Experimental: Nitrate-containing: Experimental 10 grams of nitrate-depleted beetroot concentrate balanced for anti-oxidant content diluted in 120-180 milliliters of water. Placebo: Nitrate-depleted: Placebo
Age, Categorical <=18 years	0 Participants n=41 Participants
Age, Categorical Between 18 and 65 years	11 Participants n=41 Participants
Age, Categorical >=65 years	5 Participants n=41 Participants
Age, Continuous	63 years STANDARD_DEVIATION 6.9 • n=41 Participants
Sex: Female, Male Female	9 Participants n=41 Participants
Sex: Female, Male Male	7 Participants n=41 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=41 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	16 Participants n=41 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=41 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=41 Participants
Race (NIH/OMB) Asian	0 Participants n=41 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=41 Participants
Race (NIH/OMB) Black or African American	0 Participants n=41 Participants
Race (NIH/OMB) White	16 Participants n=41 Participants
Race (NIH/OMB) More than one race	0 Participants n=41 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=41 Participants

PRIMARY outcome

Timeframe: Baseline and 2 hours following nitrate-depleted placebo beetroot juice or nitrate-containing beetroot juice

Common carotid artery compliance measured by ultrasonography and applanation tonometry. Carotid compliance is the change in carotid diameter per change in carotid pulse pressure.

Outcome measures

Outcome measures
Measure	Beetroot Juice n=16 Participants 10-grams of nitrate-containing beetroot concentrate diluted in 120-180 milliliters of water. Experimental: Nitrate-containing: Experimental	Placebo Beetroot Juice n=16 Participants 10 grams of nitrate-depleted beetroot concentrate balanced for anti-oxidant content diluted in 120-180 milliliters of water. Placebo: Nitrate-depleted: Placebo
Change in Carotid Artery Compliance in mm/mmHg x 10-1 Baseline	0.88 mm/mmHg x 10-1 Standard Error 0.01	0.87 mm/mmHg x 10-1 Standard Error 0.01
Change in Carotid Artery Compliance in mm/mmHg x 10-1 Post 2 hours	0.90 mm/mmHg x 10-1 Standard Error 0.01	0.79 mm/mmHg x 10-1 Standard Error 0.01

PRIMARY outcome

Timeframe: Baseline and 2 hours following nitrate-depleted beetroot juice or nitrate-containing beetroot juice

Carotid Augmentation Index is calculated as the augmentation pressure divided by the pulse pressure, and expressed as a percentage. Higher augmentation index percentage is a worse outcome than lower percentage.

Outcome measures

Outcome measures
Measure	Beetroot Juice n=16 Participants 10-grams of nitrate-containing beetroot concentrate diluted in 120-180 milliliters of water. Experimental: Nitrate-containing: Experimental	Placebo Beetroot Juice n=16 Participants 10 grams of nitrate-depleted beetroot concentrate balanced for anti-oxidant content diluted in 120-180 milliliters of water. Placebo: Nitrate-depleted: Placebo
Change in Carotid Augmentation Index Baseline	11 % of aug blood pressure to pulse pressur Standard Error 2	10 % of aug blood pressure to pulse pressur Standard Error 5
Change in Carotid Augmentation Index Post 2 hours	19 % of aug blood pressure to pulse pressur Standard Error 3	17 % of aug blood pressure to pulse pressur Standard Error 3

PRIMARY outcome

Timeframe: Baseline and 2 hours following nitrate-depleted beetroot juice or nitrate-containing beetroot juice

Carotid pulse pressure measured by carotid tonometry calibrated to brachial mean and diastolic pressure. Carotid pulse pressure is the difference between carotid systolic blood pressure and diastolic blood pressure.

Outcome measures

Outcome measures
Measure	Beetroot Juice n=16 Participants 10-grams of nitrate-containing beetroot concentrate diluted in 120-180 milliliters of water. Experimental: Nitrate-containing: Experimental	Placebo Beetroot Juice n=16 Participants 10 grams of nitrate-depleted beetroot concentrate balanced for anti-oxidant content diluted in 120-180 milliliters of water. Placebo: Nitrate-depleted: Placebo
Change in Carotid Pulse Pressure in mmHg Baseline	45 mmHg Standard Error 3	44 mmHg Standard Error 3
Change in Carotid Pulse Pressure in mmHg Post 2 hours	48 mmHg Standard Error 3	51 mmHg Standard Error 3

Adverse Events

Placebo

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Beetroot Juice

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Gary Pierce

University of Iowa

Phone: 319-335-9487

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place