US researchers have found that nitrite, a common small ion in the blood, also found in leafy green vegetables and red meat, could help treat high blood pressure, heart attacks and sickle cell disease.
The team from the US government-funded National Institutes of Health report that nitrite improves blood flow by opening blood vessels. It therefore increases oxygen in the blood helping the body combat related diseases.
Nitrite is present in leafy green vegetables and also responsible for the red colour of some meat. However further study will be needed to determine if dietary sources of nitrite can affect blood flow and bloodpressure.
"The importance of this work is that no one considered thismolecule to have any significant function and it isrelatively abundant in the blood stream," said Dr MarkGladwin, senior investigator in Critical Care Medicine, at the NIH Clinical Center and an author of the article.
Nitrite levels have been shown to be low in patients with high blood pressure.
The study also describes a newly discovered function forthe haemoglobin molecule itself, perhaps the most studiedprotein in human history. The researchers demonstrated thatwhen haemoglobin releases its oxygen in regions of the bodywith low oxygen (such as organs) or high metabolism, it canthen convert nitrite to nitric oxide, which is known todilate blood vessels.
Gladwin and coauthor Dr Richard Cannon studied 18 healthy volunteers who were enrolled in a physiological study. They wereinfused with sodium nitrite to determine whether nitriteaffects blood flow. They showed that blood flow increasedby 175 per cent.
"We saw a huge improvement in blood flow," said Gladwin."Nitrite helps get more blood to regions of the body withlow oxygen, such as kidneys, the heart, the brain andmuscles. This has potential as a new therapy that waspreviously overlooked."
However, he warned that at high concentrations the chemical can be toxic and clinical trials, now in progress at NIH, are required to establish its clinical usefulness in various diseases.
The article will be published in theDecember issue of Nature Medicine and was published in advance, online, on 2 November.