Although dietary nitrate is known to improve exercise, both in terms of endurance and high-intensity exercise, researchers still have a lot to learn about why this effect occurs and how our bodies convert the dietary nitrate we ingest. into nitric oxide that our cells can use.
To help answer these questions, researchers tracked the distribution of ingested nitrate in the saliva, blood, muscle, and urine of ten healthy volunteers, who were then asked to perform a leg-maximal exercise. The team wanted to find out where in the body dietary nitrate was acting, to give clues to the mechanisms at work.
The study carried out by the University of Exeter (United Kingdom) has found that the consumption of dietary nitrate, the active molecule in beetroot juice, significantly increases muscle strength during exercise.
One hour after taking the nitrate, the participants were asked to perform 60 contractions of the quadriceps (the muscle in the thigh that is activated when you straighten the knee) at maximum intensity for five minutes on an exercise machine.
The team discovered a significant increase in nitrate levels in the muscle. During the exercises, the researchers found that this increase in nitrate caused a seven percent increase in muscle strength, compared to when the participants took a placebo.
‘Our research has already provided extensive evidence of the performance-enhancing properties of dietary nitrate, commonly present in beetroot juice. It is exciting that this latest study provides the best evidence to date on the mechanisms that explain why dietary nitrate improves human muscle performance,” said study leader Andy Jones, Professor of Applied Physiology at the University of Exeter.
Previous studies had detected an increase in nitrate in tissues and body fluids after ingesting labeled dietary nitrate. By using the tracer in the new study, the researchers were able to assess precisely where nitrate is increased and activated, and also shed new light on how the nitrate we consume is used to improve 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. These results have significant implications not only for the field of exercise, but possibly for other medical areas such as those targeting neuromuscular and metabolic diseases related to nitric oxide deficiency,” said another of the authors, Barbora Piknova.
