Researchers have found that consuming nitrates in the diet – the active molecule in beetroot juice – can increase muscle strength during exercise, which may lead to better training supplements.
While previous research has shown that nitrates in the diet improve exercise, it was unclear how the body converts this molecule into the chemical nitric oxide to be used by our cells.
In a new study published earlier this month in the journal Acta PhysiologicaResearchers tracked the distribution of ingested nitrates in the saliva, blood, muscles and urine of ten healthy volunteers who performed leg exercises.
Researchers have studied where in the body nitrate molecules in the diet are active to better understand the mechanisms involved.
During a workout that involved 60 thigh muscle contractions at maximum intensity for more than five minutes, the researchers found a significant increase in nitrate levels in the quadriceps.
They say the nitrate injection led to an increase in muscle strength of about seven percent, compared to when participants took a placebo.
“Our research has already provided ample evidence of the performance-enhancing dietary properties of nitrates, commonly found in beetroot juice,” said study co-author Andy Jones of the University of Exeter in the UK.
“Interestingly, this latest study provides the best evidence yet on the mechanisms behind why dietary nitrates improve human muscle performance,” added Dr Jones.
Previous studies have shown an increase in nitrates in tissues and body fluids after ingestion of labeled dietary nitrates.
But in new research, scientists were able to gauge exactly where nitrates are increased and active.
They were also able to shed new light on how ingested nitrates are used by the body to increase exercise performance.
Citing the limitations of the study, the researchers said that while nitrate supplementation in the diet often comes in the form of beetroot juice, they say it’s unclear how the results might have differed if the drink had been consumed by participants.
Since the research was conducted on a population of young men, the researchers say more research is needed to determine how women and the elderly responded to supplementation.
“This study provides the first direct evidence that muscle nitrate levels are important for exercise performance, possibly acting as a source of nitric oxide,” said Barbora Piknova, another study author from the US National Institutes of Health.
“These results have significant implications not only for the field of exercise, but perhaps for other fields of medicine, such as neuromuscular and metabolic diseases related to nitric oxide deficiency,” Dr. Piknova added.