Influence of dietary nitrate supplementation on lung function and exercise gas exchange in COPD patients
Behnia M, Wheatley CM, Avolio A, Johnson BD
Nitric oxide : biology and chemistry · 24 citations
Review labels
Neutral facts our review recorded about how this study was done. They describe method, never whether we like the result.
How it was studied
- Design
- Randomized controlled trial (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
- Intake measured by
- Not stated
Who paid for it
- Funding
- Funding not disclosed
Publication
- Published
- 2018-03-18 · Nitric Oxide · vol. 76 · pp. 53–61
- Publisher
- Elsevier BV
- Cited
- 28 citations · more than 91% of similar papers · 2.8× the field average
- Impact
- Top 10% most cited in its field
- References
- 53 works
- Access
- Open access (hybrid journal) · CC-BY-NC-ND
- Research areas
- Chronic Obstructive Pulmonary Disease (COPD) Research · Cardiovascular and exercise physiology · Nitric Oxide and Endothelin Effects
- Keywords
- Exhaled nitric oxide, DLCO, Spirometry, Nitric oxide, Diffusing capacity, Medicine, Pulmonary function testing, COPD, Internal medicine, Cardiology, Placebo, pCO2, Respiratory system, Pulmonary Diffusing Capacity, Arterial blood, Anesthesia, Lung, Lung function, Asthma, Pathology
- MeSH
- lung, humans, pulmonary disease, chronic obstructive, nitrogen oxides, pulmonary gas exchange, exercise, dietary supplements, aged, female, male
4 authors
From US, AU
- Mehrdad M Behnia · correspondingAdventHealth Orlando; AdventHealth
- Courtney M. WheatleyMayo Clinic in Arizona
- Alberto P. AvolioMacquarie University
- Bruce D. JohnsonMayo Clinic in Arizona
Abstract
Background
During exercise as pulmonary blood flow rises, pulmonary capillary blood volume increases and gas exchange surface area expands through distention and recruitment. We have previously demonstrated that pulmonary capillary recruitment is limited in COPD patients with poorer exercise tolerance. Hypoxia and endothelial dysfunction lead to pulmonary vascular dysregulation possibly in part related to nitric oxide related pathways.
Purpose
To determine if increasing dietary nitrate might influence lung surface area for gas exchange and subsequently impact exercise performance.
Methods
Subjects had stable, medically treated COPD (n = 25), gave informed consent, filled out the St George Respiratory Questionnaire (SGRQ), had a baseline blood draw for Hgb, performed spirometry, and had exhaled nitric oxide (exNO) measured. Then they performed the intra-breath (IB) technique for lung diffusing capacity for carbon monoxide (DLCO) as well as pulmonary blood flow (Qc). Subsequently they completed a progressive semi-recumbent cycle ergometry test to exhaustion with measures of oxygen saturation (SpO2) and expired gases along with DLCO and Qc measured during the 1st work load only. Subjects were randomized to nitrate supplement group (beetroot juice) or placebo group (black currant juice) for 8 days and returned for repeat of the above protocol.
Results
Exhaled nitric oxide levels rose >200% in the nitrate group (p 2 or other measures of respiratory gas exchange. There was a tendency for the exercise DLCO to increase slightly in the nitrate group with a trend towards a rise in the DLCO/Qc relationship (p = 0.08) but not in the placebo group. The only other significant finding was a fall in the exercise blood pressure in the nitrate group, but not placebo group (p < 0.05).
Conclusion
Despite evidence of a rise in exhaled nitric oxide levels with nitrate supplementation, there was minimal evidence for improvement in exercise performance or pulmonary gas exchange surface area in a stable medically treated COPD population.
Abstract via Europe PMC. Copyright remains with the authors or publisher (CC BY-NC-ND).
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