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| Name | Class |
|---|---|
| Neogenis Laboratories | OTHER |
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The main purpose/s of this study is to examine the effects of 4 weeks of dietary nitrate supplementation on peripheral chemoreceptor sensitivity, spontaneous baroreflex sensitivity, and blood pressure responsiveness to a variety of physiological stressors in older healthy adults. We will also examine the effect of dietary nitrate supplementation on measures of central artery stiffness and aortic blood pressure in older adults. Lastly, we will also recruit a group of young subjects in order to help characterize the age-related changes associated with the physiological outcome measures of the present study.
1 in 3 adults in the U.S. have hypertension which is known to increase the risk of heart disease and stroke. Blood pressure regulation is mediated by many factors including but not limited to metabolic factors, pressure/stretch sensing receptors located in the aorta and carotid arteries, endothelial cell function, and kidney function (via water and sodium absorption/excretion). It has been shown that many of these regulatory mechanisms are altered and/or become dysfunctional with aging. Specifically older adults commonly demonstrate a decreased sensitivity in pressure receptors and/or endothelial dysfunction. Additionally with aging, there is an increase in sympathetic nervous system activity and arterial stiffness which can contribute to higher blood pressure. The important vasodilator, nitric oxide (NO), has been implicated as a key signaling molecule involved in several of the mechanisms in blood pressure regulation outlined above. A decreased NO production or bioavailability is thought to contribute to several of the physiologic changes that come with aging. Therefore, the overall aim of this study is to use a randomized, double-blind crossover, placebo controlled study to examine the effects of acute dietary nitrate supplementation (to boost bioavailable NO) on various parameters of blood pressure regulation and responsiveness in normal healthy older adults. Our main hypothesis is that 4 weeks of dietary nitrate supplementation will decrease the blood pressure responses in older adults in response to a variety of physiological stressors.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Beetroot crystals (nitrate), then placebo | Experimental | Participants will receive a nitrate rich beetroot powder (10g/day) for 4 weeks. After a washout period of 4 weeks, they will then receive the placebo (beetroot powder, no nitrate) for 4 weeks. |
|
| Placebo, then beetroot crystals (nitrate) | Experimental | Participants will receive a beetroot powder placebo (no nitrate) for 4 weeks. After a 4 week washout period, they will receive the nitrate rich beetroot powder for 4 weeks. |
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| Young Comparison | No Intervention | Young control group, used for age-related comparisons. This group did not go through any intervention. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Super Beets | Dietary Supplement | Nitrate rich beetroot powder (10g/day) for 4 weeks |
|
| Measure | Description | Time Frame |
|---|---|---|
| Change in Carotid Chemosensitivity Following 4 Weeks of Dietary Nitrate Supplementation and Placebo in Older Adults | Carotid chemosensitivity examined by measuring hypoxia ventilatory responsiveness in older adults before and after 4 weeks of beet root juice supplementation and placebo. Chemoreflex sensitivity was quantified as the change in ventilation in relation to the change in pulse oxygen saturation. | Pre and post 4 weeks dietary nitrate supplementation and pre and post 4 weeks of placebo. |
| Change in Systolic Blood Pressure During Metaboreflex Testing Following 4 Weeks of Dietary Nitrate Supplementation and Placebo in Older Adults. | Muscle metaboreflex examined by measuring systolic blood pressure responses to ischemic isometric muscle contraction in older adults before and after 4 weeks of beet root juice supplementation and placebo. | Pre and post 4 weeks dietary nitrate supplementation and pre and post 4 weeks of placebo. |
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Two separate age groups were included.
Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Darren Casey, PhD. | University of Iowa | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Iowa | Iowa City | Iowa | 52242 | United States |
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| ID | Title | Description |
|---|---|---|
| FG000 | Nitrate First Arm | Subjects consumed beet root juice with nitrate for 4 weeks during the first arm of the study. After a 4 week washout period, subjects consumed beetroot juice without nitrate (placebo) for 4 weeks. |
| FG001 | Placebo First Arm | Subjects consumed beet root juice without nitrate (placebo) for 4 weeks during the first arm of the study. After a 4 week washout period, subjects consumed beetroot juice with nitrate for 4 weeks. |
| FG002 | Young Comparison Group | Young subjects only completed a single experimental visit and no intervention. Data from young were used for age-related comparisons at baseline. |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Baseline 1 |
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| Post 1 |
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| Baseline 2 |
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| Post 2 |
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| ID | Title | Description |
|---|---|---|
| BG000 | Nitrate First Arm | Subjects consumed beet root juice with nitrate for 4 weeks during the first arm of the study. After a 4 week washout period, subjects consumed beetroot juice without nitrate (placebo) for 4 weeks. |
| BG001 | Placebo First Arm |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical | Count of Participants |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Change in Carotid Chemosensitivity Following 4 Weeks of Dietary Nitrate Supplementation and Placebo in Older Adults | Carotid chemosensitivity examined by measuring hypoxia ventilatory responsiveness in older adults before and after 4 weeks of beet root juice supplementation and placebo. Chemoreflex sensitivity was quantified as the change in ventilation in relation to the change in pulse oxygen saturation. | Posted | Mean | Standard Error | L/min/%SpO2 | Pre and post 4 weeks dietary nitrate supplementation and pre and post 4 weeks of placebo. |
|
The length of study enrollment of each older subject (~3 months). Young subjects only completed one single study visit.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Nitrate | Subjects consumed beet root juice with nitrate for 4 weeks. | 0 |
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All subjects (young and older) completed the initial study visit. The young adults were used as a comparison group only and did not go through any intervention. The older adults underwent the intervention and completed a total of four study visits.
| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Dr. Darren P. Casey | University of Iowa | 3193841009 | darren-casey@uiowa.edu |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| ICF | No | No | Yes | Informed Consent Form | Jul 28, 2016 | Oct 12, 2018 | ICF_000.pdf |
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Jul 1, 2015 | Jul 29, 2019 | Prot_SAP_001.pdf |
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| ID | Term |
|---|---|
| D000860 | Hypoxia |
| ID | Term |
|---|---|
| D012818 | Signs and Symptoms, Respiratory |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
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| Super Beets Placebo | Dietary Supplement | Nitrate deficient beetroot powder (10g/day) for 4 weeks |
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| NOT COMPLETED |
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| NOT COMPLETED |
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| NOT COMPLETED |
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Subjects consumed beet root juice without nitrate (placebo) for 4 weeks during the first arm of the study. After a 4 week washout period, subjects consumed beetroot juice with nitrate for 4 weeks. |
| BG002 | Young Comparison Group | Young control group, used for age-related comparisons. This group did not go through any intervention. |
| BG003 | Total | Total of all reporting groups |
| Participants |
|
| Age, Continuous | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | years |
|
| Sex: Female, Male | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
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| Race (NIH/OMB) | Count of Participants | Participants |
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| Region of Enrollment | Number | participants |
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| Body Mass Index | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | kg/m^2 |
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| Systolic Blood Pressure | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | mmHg |
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| Diastolic Blood Pressure | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | mmHg |
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| Glucose | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | mg/dl |
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| Total Cholesterol | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | mg/dl |
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| HDL | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | mg/dl |
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| LDL | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | mg/dl |
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| Triglycerides | Row population reflect each distinct age group. Row older adults =13 subjects. Row young adults = 10 subjects. Together the two age groups (rows) total the overall 23 subjects enrolled in the study. | Mean | Standard Deviation | mg/dl |
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| OG002 | Placebo Pre | Subjects randomized to the placebo group for 4 weeks. Values reflect pre intervention measures. |
| OG003 | Placebo Post | Subjects randomized to the placebo group for 4 weeks. Values reflect post intervention measures. |
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| Primary | Change in Systolic Blood Pressure During Metaboreflex Testing Following 4 Weeks of Dietary Nitrate Supplementation and Placebo in Older Adults. | Muscle metaboreflex examined by measuring systolic blood pressure responses to ischemic isometric muscle contraction in older adults before and after 4 weeks of beet root juice supplementation and placebo. | Posted | Mean | Standard Error | mmHg | Pre and post 4 weeks dietary nitrate supplementation and pre and post 4 weeks of placebo. |
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| 13 |
| 0 |
| 13 |
| 0 |
| 13 |
| EG001 | Placebo | Subjects consumed beet root juice without nitrate (placebo) for 4 weeks. | 0 | 13 | 0 | 13 | 0 | 13 |
| EG002 | Young Comparison Group | Subjects completed one single study visit. | 0 | 10 | 0 | 10 | 0 | 10 |
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| Between 18 and 65 years |
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| >=65 years |
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| Title | Measurements |
|---|---|
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| Male |
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| Not Hispanic or Latino |
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| Unknown or Not Reported |
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| Asian |
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| Native Hawaiian or Other Pacific Islander |
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| Black or African American |
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| White |
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| More than one race |
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| Unknown or Not Reported |
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