Dose-response Effect of Dietary Nitrate on Muscle Function in Older Individuals
| Status: | Recruiting |
|---|---|
| Conditions: | Healthy Studies, Orthopedic |
| Therapuetic Areas: | Orthopedics / Podiatry, Other |
| Healthy: | No |
| Age Range: | 65 - 79 |
| Updated: | 2/28/2019 |
| Start Date: | September 1, 2018 |
| End Date: | July 31, 2019 |
| Contact: | Richard L Hoffman, MS |
| Email: | richoffm@iu.edu |
| Phone: | 3172740648 |
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).
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).
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.
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.
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
We found this trial at
1
site
Indianapolis, Indiana 46202
Phone: 317-274-0648
Click here to add this to my saved trials
