Diets rich in green, leafy vegetables have been shown to lower BP and reduce the risk of cardiovascular disease. Green, leafy vegetables and beetroots are particularly rich in inorganic nitrate. Dietary nitrate supplementation, via sequential reduction to nitrite and NO, has previously been shown to lower BP and improve endothelial function in healthy humans.We sought to determine if supplementing dietary nitrate with beetroot juice, a rich source of nitrate, will lower BP, improve endothelial function and insulin sensitivity in individuals with type 2 diabetes (T2DM). Twenty-seven patients, age 67.2 +/-4.9 years, (18 male) were recruited for a double blind, randomised, placebo-controlled crossover trial. Participants were randomised to begin in either order a 2 week period of supplementation with 250 ml beetroot juice daily (active) or 250 ml nitratedepleted beetroot juice (placebo). At the conclusion of each intervention period 24 hour ambulatory blood pressure monitoring, tests of macro and microvascular endothelial function and a hyperinsulinaemic isoglycaemic clamp were performed. After two weeks administration of beetroot juice mean ambulatory systolic BP was unchanged: 134.6 ± 8.4 mmHg versus 135.1 ± 7.8 mmHg (mean ± SD) placebo vs. active -mean difference of -0.5 mmHg (placebo-active), p=0.737 (95% CI -3.9 to 2.8). There were no changes in macrovascular or microvascular endothelial function or insulin sensitivity. Supplementation of the diet with 7.5 mmoles of nitrate per day for 2 weeks caused an increase in plasma nitrite and nitrate concentration, but did not lower BP, improve endothelial function or insulin sensitivity in individuals with T2DM.3

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We have developed an effective placebo beetroot juice for use in trials of supplementation of dietary nitrate. Two weeks supplementation of the diet with 7.5 mmol of nitrate per day caused a significant improvement in simple reaction time in individuals with T2DM.