Aging, Sarcopenia
Conditions
Keywords
nitric oxide
Brief summary
Nitrate is a naturally-occurring substance found in foods, especially green leafy vegetables and beets. Increasing nitrate intake (by drinking beetroot juice (BRJ) has been shown to improve muscle function young and middle-aged subjects, athletes, and patients with heart failure. The purpose of this study is to determine whether dietary nitrate provides a similar benefit in older individuals, and if so, the optimal dose. We will be comparing the effects of ingesting BRJ containing a smaller or greater amount of nitrate versus the effects of a placebo (BRJ from which the nitrate has been removed).
Detailed description
This study consists of four visits that will take a minimum of 15 days to complete. Study Visit One (Screening) 1-2 hours The purpose of the screening visit is to explain all aspects of the study. The investigators will also determine if individuals can participate in the study. Eligible subjects will undergo a complete medical history and physical exam. They will have their blood drawn, and will provide a urine sample (to determine if they are pregnant). Subjects will also practice the entire neuromuscular function exercise test. During this test, the strength of the subject's muscles will be determined by having them kick, push and/or pull back as hard as they can while their leg is strapped to an exercise device. Blood pressure and heart rate and rhythm will be monitored. Subjects will be instructed to consume their normal diet throughout the study. However, they will be asked to avoid eating foods high in nitrate such as beets, spinach, and collard greens the evening before each visit. They will be asked to refrain from the use of antibacterial mouthwash, such as Listerine or Cepacol, during the study. Subjects will also be asked to not chew gum or to consume alcohol or food and drinks that contain caffeine for 24 hour before each visit. This includes coffee, tea, chocolate and soft drinks such as Mountain Dew. Finally, they will be asked to fast for 12 hour prior to each study visit. Study Visit Two - Approximately 5 hours At the beginning of this visit a catheter (small, flexible, sterile plastic tube) will be placed through a vein in one of the subject's arms. This is for collection of blood samples. Blood will be drawn four times during this visit. Each draw will be 6mL or about 1.2 teaspoons. The first blood draw will check nitrate and nitrogen levels. Subjects will then have a breath test to check nitric oxide. They will then drink about 280 mL (about 1 cup) of BRJ. In one trial, this will be a placebo, that is, BRJ from which the essentially all of the nitrate has been removed. In another trial, they will drink BRJ still containing nitrate. In a third trial, they will drink an equal mixture of the placebo and nitrate-containing BRJ. Blood and breath samples will be obtained every hour. Heart rate and blood pressure will be measured at the same times the blood and breath samples are obtained. About 2 hours after ingestion of BRJ (or placebo) subjects will be asked to perform the neuromuscular function test that was practiced during the screening visit. After completing the exercise test one final blood and breath sample will be obtained. Study Visits Three and Four The same procedures completed during Study Visit Two will be performed. The order of treatment (placebo vs. lower dose vs. higher dose of nitrate) will be randomized using a computer program. Neither the subjects nor the investigators will know the treatment they receive during each visit until the entire study is completed.
Interventions
DIETARY_SUPPLEMENTBeet root juice
Beet root juice
Sponsors
Indiana University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
Double-blind, placebo-controlled, crossover
Eligibility
Sex/Gender
ALL
Age
65 Years to 79 Years
Healthy volunteers
Yes
Inclusion criteria
• In good health, as determined by the investigator's review of history (provided by subject at screening visit), physical examination, and routine blood and urine tests (done at screening visit)
Exclusion criteria
* Men and women \<65 or \>79 years of age * Unable to provide informed consent * Currently pregnant or lactating (given the age range for the study, verbal confirmation by subject is believed to be sufficient) * Current smokers * Significant orthopedic limitations or other contraindications to strenuous exercise * Those taking phosphodiesterase inhibitors (e.g., Viagra) * Those taking proton pump inhibitors, antacids, xanthine oxidase inhibitors, or on hormone replacement therapy * Those taking anti-coagulants (e.g., Coumadin) or on anti-platelet therapy * History of neuromuscular disease (e.g., cervical spondylotic radiculomyelpathy, lumbar spondylosis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, and acquired demyelinating polyneuropathies), cardiovascular disease (e.g., \> stage I hypertension, heart failure, myocardial infarction/ischemia, significant myocardial or pericardial diseases (e.g. amyloidosis, constriction), moderate or severe valvular disease, renal disease, liver disease, or anemia
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Maximal Knee Extensor Velocity | 1 day | Maximal knee extensor velocity determined using isokinetic dynamometry |
| Maximal Knee Extensor Power | 1 day | Maximal knee extensor power determined using isokinetic dynamometry |
Secondary
| Measure | Time frame |
|---|---|
| Plasma Nitrite | 0, 1, 2, 3 h after ingestion |
| Plasma Nitrate | 0, 1, 2, 3 h after ingestion |
| Breath Nitric Oxide | 0, 1, 2, 3 h after ingestion |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Placebo Then Low Then High 3.3 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day), washout (7 days), 1.55 mL/kg concentrated beet root juice containing nitrate + 1.55 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day), washout (7 days), 3.3 mL/kg concentrated beet root juice containing nitrate (1 day) | 2 |
| Low Then High Then Placebo 1.55 mL/kg concentrated beet root juice containing nitrate + 1.55 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day), washout (7 days), 3.3 mL/kg concentrated beet root juice containing nitrate (1 day), washout (7 days), 3.3 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day) | 3 |
| High Then Placebo Then Low 3.3 mL/kg concentrated beet root juice containing nitrate (1 day), washout (7 days), 3.3 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day), washout (7 days), 1.55 mL/kg concentrated beet root juice containing nitrate + 1.55 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day) | 2 |
| High Then Low Then Placebo 3.3 mL/kg concentrated beet root juice containing nitrate (1 day)washout (7 days), 1.55 mL/kg concentrated beet root juice containing nitrate + 1.55 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day), washout (7 days), 3.3 mL/kg concentrated beet root juice \*depleted of nitrate\* (1 day) | 2 |
| Total | 9 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 |
|---|---|---|---|---|---|
| Overall Study | Adverse Event | 1 | 0 | 1 | 0 |
| Overall Study | screen failure | 0 | 1 | 0 | 1 |
Baseline characteristics
| Characteristic | Placebo Then Low Then High | Total | High Then Low Then Placebo | High Then Placebo Then Low | Low Then High Then Placebo |
|---|---|---|---|---|---|
| Age, Continuous | 69 years STANDARD_DEVIATION 4 | 70 years STANDARD_DEVIATION 3 | 70 years STANDARD_DEVIATION 4 | 70 years STANDARD_DEVIATION 4 | 72 years STANDARD_DEVIATION 1 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 2 Participants | 9 Participants | 2 Participants | 2 Participants | 3 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 2 Participants | 9 Participants | 2 Participants | 2 Participants | 3 Participants |
| Region of Enrollment United States | 2 participants | 9 participants | 2 participants | 2 participants | 3 participants |
| Sex: Female, Male Female | 1 Participants | 8 Participants | 2 Participants | 2 Participants | 3 Participants |
| Sex: Female, Male Male | 1 Participants | 1 Participants | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 9 |
| other Total, other adverse events | 0 / 9 |
| serious Total, serious adverse events | 0 / 9 |
Outcome results
Primary
Maximal Knee Extensor Power
Maximal knee extensor power determined using isokinetic dynamometry
Time frame: 1 day
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Placebo | Maximal Knee Extensor Power | 3.74 W/kg | Standard Deviation 1.19 |
| Low Nitrate | Maximal Knee Extensor Power | 3.92 W/kg | Standard Deviation 1.1 |
| High Nitrate | Maximal Knee Extensor Power | 3.69 W/kg | Standard Deviation 1.04 |
p-value: 0.0131ANOVA
Primary
Maximal Knee Extensor Velocity
Maximal knee extensor velocity determined using isokinetic dynamometry
Time frame: 1 day
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Placebo | Maximal Knee Extensor Velocity | 10.83 rad/s | Standard Deviation 2.41 |
| Low Nitrate | Maximal Knee Extensor Velocity | 11.91 rad/s | Standard Deviation 2.01 |
| High Nitrate | Maximal Knee Extensor Velocity | 11.24 rad/s | Standard Deviation 2.32 |
p-value: 0.0833ANOVA
Secondary
Breath Nitric Oxide
Time frame: 0, 1, 2, 3 h after ingestion
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Breath Nitric Oxide | 0 h | 19 ppm | Standard Deviation 10 |
| Placebo | Breath Nitric Oxide | 1 h | 22 ppm | Standard Deviation 10 |
| Placebo | Breath Nitric Oxide | 2 h | 25 ppm | Standard Deviation 10 |
| Placebo | Breath Nitric Oxide | 3 h | 21 ppm | Standard Deviation 11 |
| Low Nitrate | Breath Nitric Oxide | 3 h | 50 ppm | Standard Deviation 31 |
| Low Nitrate | Breath Nitric Oxide | 0 h | 18 ppm | Standard Deviation 9 |
| Low Nitrate | Breath Nitric Oxide | 2 h | 43 ppm | Standard Deviation 21 |
| Low Nitrate | Breath Nitric Oxide | 1 h | 39 ppm | Standard Deviation 18 |
| High Nitrate | Breath Nitric Oxide | 3 h | 36 ppm | Standard Deviation 17 |
| High Nitrate | Breath Nitric Oxide | 1 h | 31 ppm | Standard Deviation 12 |
| High Nitrate | Breath Nitric Oxide | 2 h | 36 ppm | Standard Deviation 12 |
| High Nitrate | Breath Nitric Oxide | 0 h | 18 ppm | Standard Deviation 8 |
p-value: 0.017215ANOVA
Secondary
Plasma Nitrate
Time frame: 0, 1, 2, 3 h after ingestion
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Plasma Nitrate | 0 h | 55 umol/L | Standard Deviation 31 |
| Placebo | Plasma Nitrate | 1 h | 57 umol/L | Standard Deviation 14 |
| Placebo | Plasma Nitrate | 2 h | 67 umol/L | Standard Deviation 17 |
| Placebo | Plasma Nitrate | 3 h | 66 umol/L | Standard Deviation 16 |
| Low Nitrate | Plasma Nitrate | 3 h | 628 umol/L | Standard Deviation 142 |
| Low Nitrate | Plasma Nitrate | 0 h | 40 umol/L | Standard Deviation 16 |
| Low Nitrate | Plasma Nitrate | 2 h | 624 umol/L | Standard Deviation 158 |
| Low Nitrate | Plasma Nitrate | 1 h | 523 umol/L | Standard Deviation 155 |
| High Nitrate | Plasma Nitrate | 3 h | 1296 umol/L | Standard Deviation 282 |
| High Nitrate | Plasma Nitrate | 1 h | 793 umol/L | Standard Deviation 218 |
| High Nitrate | Plasma Nitrate | 2 h | 1184 umol/L | Standard Deviation 266 |
| High Nitrate | Plasma Nitrate | 0 h | 34 umol/L | Standard Deviation 14 |
p-value: 2e-8ANOVA
Secondary
Plasma Nitrite
Time frame: 0, 1, 2, 3 h after ingestion
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Placebo | Plasma Nitrite | 1 h | .299 umol/L | Standard Deviation 0.067 |
| Placebo | Plasma Nitrite | 0 h | .306 umol/L | Standard Deviation 0.138 |
| Placebo | Plasma Nitrite | 3 h | .347 umol/L | Standard Deviation 0.14 |
| Placebo | Plasma Nitrite | 2 h | .326 umol/L | Standard Deviation 0.113 |
| Low Nitrate | Plasma Nitrite | 0 h | 40 umol/L | Standard Deviation 16 |
| Low Nitrate | Plasma Nitrite | 3 h | .820 umol/L | Standard Deviation 0.543 |
| Low Nitrate | Plasma Nitrite | 2 h | .528 umol/L | Standard Deviation 0.219 |
| Low Nitrate | Plasma Nitrite | 1 h | .459 umol/L | Standard Deviation 0.203 |
| High Nitrate | Plasma Nitrite | 3 h | 1.216 umol/L | Standard Deviation 0.458 |
| High Nitrate | Plasma Nitrite | 2 h | .949 umol/L | Standard Deviation 0.535 |
| High Nitrate | Plasma Nitrite | 1 h | .478 umol/L | Standard Deviation 0.219 |
| High Nitrate | Plasma Nitrite | 0 h | .341 umol/L | Standard Deviation 0.165 |
p-value: 0.012728ANOVA