Beetroot is 85% water and about 25 kcal per portion and is rich in nitrates!
Back in 1983 the vegetarian diet was identified to offer a blood pressure lowering effect, the specific nutrients at that time were unknown. Between 1983-2006 evidence continued to emerge that beetroot may be beneficial in lowering blood pressure. This body of evidence has continued to grow.
Here's the research
A study in 2014, revealed that supplementing the diet with beetroot juice (250mls/day) could provide a long-lasting reduction in blood pressure in patients with high blood pressure, via nitrates.
The effect was similar to that of medication...although this all sounds very promising... it is still early days and more studies are needed before this approach can become a recommended treatment for high blood pressure, so don’t switch blood pressure medication for beetroot just yet!