Effect of dietary nitrate on blood pressure, endothelial function, and insulin sensitivity in type 2 diabetes.
Study Goal
The researchers sought to determine if dietary nitrate supplementation via beetroot juice would lower blood pressure, improve endothelial function, and enhance insulin sensitivity in individuals with type 2 diabetes.
Results Summary
The study found that beetroot juice supplementation increased plasma nitrite and nitrate concentrations but did not lower blood pressure, improve endothelial function, or enhance insulin sensitivity in individuals with type 2 diabetes. No significant changes were observed in any of the measured outcomes compared to placebo.
Population
27 patients with type 2 diabetes (age 67.2±4.9 years, 18 male).
Effective Dosage
250ml beetroot juice daily (containing 7.5mmol nitrate).
Duration
2 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Diets rich in green, leafy vegetables | decrease | blood pressure (BP) | - | - | have been shown to lower | #1 |
Diets rich in green, leafy vegetables | decrease | risk of cardiovascular disease | - | - | reduce | #2 |
Dietary nitrate supplementation | decrease | BP | healthy humans | - | has previously been shown to lower | #3 |
Dietary nitrate supplementation | increase | endothelial function | healthy humans | - | improve | #4 |
supplementing dietary nitrate with beetroot juice | decrease | BP | individuals with type 2 diabetes (T2DM) | - | will lower | #5 |
supplementing dietary nitrate with beetroot juice | increase | endothelial function | individuals with type 2 diabetes (T2DM) | - | improve | #6 |
supplementing dietary nitrate with beetroot juice | increase | insulin sensitivity | individuals with type 2 diabetes (T2DM) | - | improve | #7 |
beetroot juice | no change | mean ambulatory systolic BP | patients with type 2 diabetes | 134.6±8.4mmHg versus 135.1±7.8mmHg (mean±SD), placebo vs active-mean difference of -0.5mmHg (placebo-active), p=0.737 (95% CI -3.9 to 2.8) | was unchanged | #8 |
beetroot juice | no change | macrovascular endothelial function | patients with type 2 diabetes | - | no changes | #9 |
beetroot juice | no change | microvascular endothelial function | patients with type 2 diabetes | - | no changes | #10 |
beetroot juice | no change | insulin sensitivity | patients with type 2 diabetes | - | no changes | #11 |
Supplementation of the diet with 7.5mmol of nitrate per day for 2 weeks | increase | plasma nitrite and nitrate concentration | individuals with T2DM | - | caused an increase | #12 |
Supplementation of the diet with 7.5mmol of nitrate per day for 2 weeks | no change | BP | individuals with T2DM | - | did not lower | #13 |
Supplementation of the diet with 7.5mmol of nitrate per day for 2 weeks | no change | endothelial function | individuals with T2DM | - | did not improve | #14 |
Supplementation of the diet with 7.5mmol of nitrate per day for 2 weeks | no change | insulin sensitivity | individuals with T2DM | - | did not improve | #15 |
Diets rich in green, leafy vegetables have been shown to lower blood pressure (BP) and reduce the risk of cardiovascular disease. Green, leafy vegetables and beetroot 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 and 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, randomized, placebo-controlled crossover trial. Participants were randomized to begin, in either order, a 2-week period of supplementation with 250ml beetroot juice daily (active) or 250ml nitrate-depleted beetroot juice (placebo). At the conclusion of each intervention period 24-h ambulatory blood pressure monitoring, tests of macro- and microvascular endothelial function, and a hyperinsulinemic isoglycemic clamp were performed. After 2 weeks administration of beetroot juice mean ambulatory systolic BP was unchanged: 134.6±8.4mmHg versus 135.1±7.8mmHg (mean±SD), placebo vs active-mean difference of -0.5mmHg (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 7.5mmol 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 improve insulin sensitivity in individuals with T2DM.