A Wake Forest University study to investigate the effects of acute beetroot juice ingestion on the exercise capacity of COPD patients shows some promise, but a larger clinical trial is needed to verify results.
The new research, published online ahead of print in the journal Nitric Oxide: Biology and Chemistry, looked at a small group of COPD patients who drank beetroot juice as compared to a placebo drink before exercise.
Researchers recruited 15 COPD patients; 11 white males, one African-American male and three white females. Patients completed four visits. During visit one, they completed baseline pulmonary function testing, filled out health status questionnaires, had a brief medical examination and completed an incremental exercise test on a stationary bicycle to determine their maximal exercise work rate.
The second visit one week later consisted of additional pulmonary function and lung volume testing, as well as a familiarization exercise test on an exercise bicycle at 75% of the patients’ previously determined maximal work rates.
This type of exercise test has been used in previous trials with COPD patients examining the effects of pharmaceutical agents on exercise performance and is designed to exhaust the patient in a period of four to 10 minutes, said Michael Berry, who is the primary investigator and lead author of the study.
Participants were assigned to one of two treatments—beetroot juice (visit three) and placebo (visit four) or placebo (visit three) and beetroot juice (visit four). These visits were separated by at least a seven-day break.
All visits were performed at a similar time in the morning and the beetroot juice or placebo juice, about three ounces of each, was ingested two-and-a-half hours before the final two visits. Prune juice was used as the placebo because it contains similar amounts of carbohydrates, sugars and fats, but does not contain any nitrates, Berry said.
How long patients exercised during the third and fourth visits was recorded.
Berry said that while the study has its limitations, he is hopeful the data generated will lead to grant funding for a larger study to look at the mechanisms for how nitrates can improve the physical function of COPD patients.
“One of the benefits of exercise is that if you get positive results, you’re more likely to continue doing it. If beetroot juice positively impacts those results, it could motivate COPD patients to continue to be physically active and improve their health,” he said.