Avid weightlifters and fitness enthusiasts concerned about their performance are always looking for ways to increase their strength. One place to possibly look is in the produce section of your neighborhood grocery store. That’s because researchers at the University of Exeter in England found dietary nitrate, the active molecule in beetroot juice, significantly increased muscle force while exercising.
While the concept of enhanced exercise performance is not new when it comes to dietary nitrate, scientists are actively searching for why it is so. Previous studies have shown increased endurance and more results from high-intensity exercise. And that has researchers looking for how our bodies use the dietary nitrate we ingest to boost nitric oxide that can be used by our cells.
Exeter professors teamed up with colleagues from the National Institutes of Health in the U.S. for this study and published their findings in the journal Acta Physiologica. The purpose of the trial was to track the distribution of ingested nitrate in the saliva, blood, muscle and urine of 10 volunteers who were asked to perform maximal leg exercise.
Researchers were hoping to see where the dietary nitrate was active in the body in order to determine which mechanisms were at work. An hour after the volunteers ingested the nitrate, they worked out at maximum intensity over a period of five minutes. During that time they had to perform 60 repetitions on the leg extension machine. That machine involves contracting the thigh muscles to straighten the knee.
Scientists found a large increase in the amount of nitrate in the muscles. And volunteers experienced an increase in muscle force of seven percent compared to when they took a placebo.
"Our research has already provided a large body of evidence on the performance-enhancing properties of dietary nitrate, commonly found in beetroot juice," said Andy Jones, Professor of Applied Physiology at the University of Exeter. "Excitingly, this latest study provides the best evidence to date on the mechanisms behind why dietary nitrate improves human muscle performance."
Researchers used a tracer in this study to more accurately assess where nitrate is increased and active. They hope to learn more how the nitrate we consume is used by the body to enhance exercise performance.
"This study provides the first direct evidence that muscle nitrate levels are important for exercise performance, presumably by acting as a source of nitric oxide," said Dr. Barbora Piknova, research collaborator and staff scientist in the National Institute of Diabetes and Digestive and Kidney Diseases at the National Institutes of Health. "These results have significant implications not only for the exercise field, but possibly for other medical areas such as those targeting neuromuscular and metabolic diseases related to nitric oxide deficiency."