Writing in the journal Hypertension, scientists from the University of California, San Francisco, Institute of Physiology of the Czech Academy of Sciences, and Michigan State University reported that beetroot juice and nitrate supplements were more than 100 times more potent than potassium in protecting salt-sensitive rats against blood pressure rises.
“Given that leafy green and root vegetables contain large amounts of inorganic nitrate, these findings raise the possibility that fortification of salty food products with small amounts of a nitrate-rich vegetable concentrate may provide a simple method for reducing risk for salt-induced hypertension,” they wrote.
The study adds to a growing body of science supporting the potential cardiovascular benefits of beetroot juice, linked to the nitrate content.
Until relatively recently nitrate – which is abundant in green leafy vegetables – had been considered merely as an inert end product of nitric oxide (NO) metabolism or as a potentially toxic constituent in our diet.
However, the last decade has brought understanding of its importance in biological processes, including regulation of blood flow, blood pressure, cellular signaling, glucose homeostasis, and tissue responses to low oxygen levels (hypoxia). In addition, epidemiological studies have linked the intake of green leafy vegetables to a reduction in the risk of cardiovascular disease.
The researchers found that fortifying salty foods with “surprisingly small amounts” of nitrate-rich vegetable products prevented increases in blood pressure in male Dahl salt-sensitive rats.
“In the most widely studied animal model of spontaneous salt sensitivity, we found that supplemental dietary sodium nitrate confers significant and substantial protection from the pressor effects of increased salt intake when the molar ratio of added nitrate to added salt is only [approximatley] 1:170,” wrote the researchers.
“Furthermore, provision of a low molar ratio of added nitrate to added salt of [approximatley] 1:110 by supplementing the diet with beetroot and a large amount of salt also conferred significant and substantial protection against salt-induced increases in blood pressure. Beetroot treatment reduced the effect of salt loading on mean arterial pressure by 60%.
“To our knowledge, no other dietary ingredient has been identified that can provide this degree of protection against salt-induced increases in blood pressure when added to the diet in such low molar amounts relative to that of added salt.”
The researchers added that, if additional research supports the findings and they could be translated to humans, this nitrate-fortification approach may offer a way to reduce the impact of salty foods on blood pressure without affecting the taste of physical properties of the food, and thereby without affecting eating habits.
Published online ahead of print, doi: 10.1161/HYPERTENSIONAHA.118.12234
“Small Amounts of Inorganic Nitrate or Beetroot Provide Substantial Protection From Salt-Induced Increases in Blood Pressure”
Authors: R.C. Morris Jr, et al.