Dietary Nitrate and Physiological Aging

Darren P Casey

Status: Completed

Conditions: Aging

Treatments: Dietary Supplement: Super Beets Placebo; Dietary Supplement: Super Beets

Study type: Interventional

Funder types: Other

Identifiers

NCT02593305

201507735

Details and patient eligibility

About

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.

Full 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.

Enrollment: 23 patients

Sex: All

Ages: 18 to 85 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Two separate age groups were included.

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.

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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23 participants in 3 patient groups

Beetroot crystals (nitrate), then placebo

Experimental group

Description:

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.

Treatment:

Dietary Supplement: Super Beets

Dietary Supplement: Super Beets Placebo

Placebo, then beetroot crystals (nitrate)

Experimental group

Description:

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.

Treatment:

Dietary Supplement: Super Beets

Dietary Supplement: Super Beets Placebo

Young Comparison

No Intervention group

Description:

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