http://www.telegraph.co.uk/health/main.jhtml?xml=/health/2008/07/07/hbeet107.xml
So how does beetroot work in the body? Like other superfoods, it has antioxidants in abundance, and is rich in iron, boron and folic acid. Betanene, which gives it its deep colour, is even more potent an antioxidant than polyphenols, the plant chemicals thought to be a key reason for people whose diets are rich in leafy vegetables having lower blood pressure.
But, says Professor Ben Benjamin, a consultant in Acute Medicine at the Peninsula Medical School in Plymouth and member of the research team, it is beetroot's capacity to absorb and store exceptionally high levels of nitrate that earns it the super-root title. Nitrates are nutrients found in soil which all plants need to build protein, and which the body harnesses in its battle against blood pressure.
"When nitrate is present in high concentration in saliva, bacteria on the tongue converts it into a more reactive chemical, nitrite," Prof Benjamin explains. "When the nitrite is swallowed, it is easily converted into nitric oxide, a chemical which is continually produced by our blood vessels to make them relax and hence keep blood pressure low. So dramatically increasing the levels of nitrate with beetroot juice increases this effect."
Along with its anti-hypertensive effects, the study also found that the high levels of nitrates in beetroot juice work like aspirin does to prevent blood clots, and help to protect the lining of the blood vessels.