Dietary nitrate supplementation in COPD: an acute, double-blind, randomized, placebo-controlled, crossover trial

Nitric Oxide. 2015 Jan 30;44:105-11. doi: 10.1016/j.niox.2014.12.010. Epub 2014 Dec 19.

Abstract

Background: The acute consumption of dietary nitrate has been shown to improve exercise capacity in athletes, healthy adults and subjects with peripheral vascular disease. Many COPD patients have reduced exercise capacity. We hypothesized that acute nitrate consumption might increase incremental shuttle walk test (ISWT) distance in COPD subjects.

Methods: Eleven COPD subjects were randomly assigned to consume either a high nitrate or a matched, low nitrate beverage in a double-blind, randomized, placebo-controlled, crossover design. ISWT distance was measured both before and 3 h after the beverage and change was recorded. After a 7-day washout, ISWT distances were re-measured before and 3 h after the alternate beverage and changes were recorded.

Results: We observed an increase in ISWT distance after consuming the high nitrate juice (25 m) compared with a reduction after the low nitrate juice (14 m) (p < 0.01). This improvement in exercise capacity was associated with significant increases in serum nitrate (p < 0.000005) and nitrite (p < 0.01) levels and a significant lowering of resting blood pressure (<0.05).

Conclusions: In patients with stable COPD, the acute consumption of dietary nitrate increased serum nitrate/nitrite levels and exercise capacity and was associated with a decrease in resting blood pressure. Nitrate consumption might alter exercise capacity in COPD patients.

Keywords: Beetroot; COPD; Dietary nitrate; Exercise tolerance; Nitric oxide; Nitrite.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Blood Pressure / drug effects
  • Cross-Over Studies
  • Double-Blind Method
  • Exercise Test / drug effects
  • Female
  • Hemodynamics / drug effects
  • Humans
  • Male
  • Middle Aged
  • Nitrates / administration & dosage*
  • Nitrates / blood
  • Nitric Oxide / blood
  • Nitrites / blood
  • Pulmonary Disease, Chronic Obstructive / blood
  • Pulmonary Disease, Chronic Obstructive / diet therapy*
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Walking

Substances

  • Nitrates
  • Nitrites
  • Nitric Oxide