Dietary Nitrate and Physiological Aging

NCT ID: NCT02593305

Last Updated: 2019-10-14

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 23 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-10-31
• Study Completion Date: 2017-04-28

Brief Summary

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.

Detailed Description

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.

Conditions

Aging

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: DOUBLE

Study Groups

Beetroot crystals (nitrate), then placebo

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.

Group Type: EXPERIMENTAL

Super Beets

Intervention Type: DIETARY_SUPPLEMENT

Nitrate rich beetroot powder (10g/day) for 4 weeks

Super Beets Placebo

Intervention Type: DIETARY_SUPPLEMENT

Nitrate deficient beetroot powder (10g/day) for 4 weeks

Placebo, then beetroot crystals (nitrate)

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.

Group Type: EXPERIMENTAL

Super Beets

Intervention Type: DIETARY_SUPPLEMENT

Nitrate rich beetroot powder (10g/day) for 4 weeks

Super Beets Placebo

Intervention Type: DIETARY_SUPPLEMENT

Nitrate deficient beetroot powder (10g/day) for 4 weeks

Young Comparison

Young control group, used for age-related comparisons. This group did not go through any intervention.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

Super Beets

Nitrate rich beetroot powder (10g/day) for 4 weeks

Intervention Type: DIETARY_SUPPLEMENT

Super Beets Placebo

Nitrate deficient beetroot powder (10g/day) for 4 weeks

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

Beetroot crystals; Beetroot crystals no nitrate

Eligibility Criteria

Inclusion Criteria

• Healthy young adults 18-35 years of age (comparison group)
• Healthy older adults 60-85 years of age (intervention group)

Exclusion Criteria

• Hypertension, hyperlipidemia, current smoker or smoker within the last year, heart disease, diabetes, Chronic obstructive pulmonary disease, asthma, sleep apnea, Raynaud's disease, body mass index (BMI) > 30 kg/m2, allergy medication, clinical depression, autonomic disorders and other conditions or medications that might normally alter cardiovascular function, exercise tolerance, and/or blood pressure responses.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 85 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Neogenis Laboratories

OTHER

Sponsor Role: collaborator

Darren P Casey

OTHER

Sponsor Role: lead

Responsible Party

Darren P Casey

Assistant Professor

Responsibility Role: SPONSOR_INVESTIGATOR

Principal Investigators

Darren Casey, PhD.

Role: PRINCIPAL_INVESTIGATOR

University of Iowa

Locations

University of Iowa

Iowa City, Iowa, United States

Countries

United States

Provided Documents

Document Type: Informed Consent Form

View Document

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

201507735

Identifier Type: -

Identifier Source: org_study_id