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Effect of Spinach, a High Dietary Nitrate Source, on Arterial Stiffness and Related Hemodynamic Measures: A Randomized, Controlled Trial in Healthy Adults.

Jovanovski E, Bosco L, Khan K, Au-Yeung F, Ho H, Zurbau A, Jenkins AL, Vuksan V - Clin Nutr Res (2015)

Bottom Line: However, the constituents responsible for this effect have not been well established.A postprandial reduction in augmentation index was observed at 180 min on high-nitrate compared to low-nitrate intervention (-6.54 ± 9.7% vs. -0.82 ± 8.0%, p = 0.01) on Day 1, and from baseline on Day 7 (-6.93 ± 8.7%, p < 0.001; high vs. low: -2.28 ± 12.5%, p = 0.35), suggesting that the nitrate intervention is not associated with the development of tolerance for at least 7 days of continued supplementation.High vs. low-nitrate intervention also reduced central systolic (-3.39 ± 5.6 mmHg, p = 0.004) and diastolic BP (-2.60 ± 5.8 mmHg, p = 0.028) and brachial systolic BP (-3.48 ± 7.4 mmHg, p = 0.022) at 180 min following 7-day supplementation only.

View Article: PubMed Central - PubMed

Affiliation: Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Toronto, ON M5B 1W8, Canada. ; Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.

ABSTRACT
Diets rich in fruits and vegetables reduce risk of adverse cardiovascular events. However, the constituents responsible for this effect have not been well established. Lately, the attention has been brought to vegetables with high nitrate content with evidence that this might represent a source of vasoprotective nitric oxide. We hypothesized that short-term consumption of spinach, a vegetable having high dietary nitrate content, can affect the arterial waveform indicative of arterial stiffness, as well as central and peripheral blood pressure (BP). Using a placebo-controlled, crossover design, 27 healthy participants were randomly assigned to receive either a high-nitrate (spinach; 845 mg nitrate/day) or low-nitrate soup (asparagus; 0.6 mg nitrate/day) for 7 days with a 1-week washout period. On days 1 and 7, profiles of augmentation index, central, and brachial BP were obtained over 180 min post-consumption in 4 fasted visits. A postprandial reduction in augmentation index was observed at 180 min on high-nitrate compared to low-nitrate intervention (-6.54 ± 9.7% vs. -0.82 ± 8.0%, p = 0.01) on Day 1, and from baseline on Day 7 (-6.93 ± 8.7%, p < 0.001; high vs. low: -2.28 ± 12.5%, p = 0.35), suggesting that the nitrate intervention is not associated with the development of tolerance for at least 7 days of continued supplementation. High vs. low-nitrate intervention also reduced central systolic (-3.39 ± 5.6 mmHg, p = 0.004) and diastolic BP (-2.60 ± 5.8 mmHg, p = 0.028) and brachial systolic BP (-3.48 ± 7.4 mmHg, p = 0.022) at 180 min following 7-day supplementation only. These findings suggest that dietary nitrate from spinach may contribute to beneficial hemodynamic effects of vegetable-rich diets and highlights the potential of developing a targeted dietary approach in the management of elevated BP.

No MeSH data available.


Related in: MedlinePlus

Mean change from baseline in AI75 (%) of high-nitrate versus low-nitrate intervention on (A) Day 1 and (B) Day 7 in 27 healthy participants. Values are expressed as mean ± SEM. An intervention × time interaction was observed on Day 1 (p = 0.03, repeated measures ANOVA). *Significantly different from low-nitrate intervention as assessed by repeated measures ANOVA, p = 0.01.
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Figure 1: Mean change from baseline in AI75 (%) of high-nitrate versus low-nitrate intervention on (A) Day 1 and (B) Day 7 in 27 healthy participants. Values are expressed as mean ± SEM. An intervention × time interaction was observed on Day 1 (p = 0.03, repeated measures ANOVA). *Significantly different from low-nitrate intervention as assessed by repeated measures ANOVA, p = 0.01.

Mentions: A significant treatment × time interaction was observed on Day 1 for AI75 (p = 0.03, two-way ANOVA). On Day 1, there was a reduction in AI75 following the high-nitrate intervention with a maximum effect of -5.72 ± 10.8% at 180 minutes relative to control (p = 0.01) and -6.54 ± 9.7% reduction relative to baseline (p = 0.002; Figure 1). Following 7 days of intervention, the high-nitrate intervention produced a comparable reduction on AI75 from baseline when compared to Day 1 (6.93 ± 8.7%, p < 0.001). However, on Day 7, the low-nitrate intervention produced a similar effect to the high-nitrate meal, with no differences between interventions (high vs. low-nitrate: -2.28 ± 12.5%, p = 0.35; Figure 1). A significant reduction of AI75 on Day 7 compared to Day 1 was observed in the low-nitrate intervention at 120 minutes (-4.55 ± 10.3%, p = 0.03), but not at 180 minutes (-3.83 ± 10.4%, p = 0.065; Table 2). The within subject coefficient of variation for AI75 was 16.6%, in line with recently reported values [10].


Effect of Spinach, a High Dietary Nitrate Source, on Arterial Stiffness and Related Hemodynamic Measures: A Randomized, Controlled Trial in Healthy Adults.

Jovanovski E, Bosco L, Khan K, Au-Yeung F, Ho H, Zurbau A, Jenkins AL, Vuksan V - Clin Nutr Res (2015)

Mean change from baseline in AI75 (%) of high-nitrate versus low-nitrate intervention on (A) Day 1 and (B) Day 7 in 27 healthy participants. Values are expressed as mean ± SEM. An intervention × time interaction was observed on Day 1 (p = 0.03, repeated measures ANOVA). *Significantly different from low-nitrate intervention as assessed by repeated measures ANOVA, p = 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525132&req=5

Figure 1: Mean change from baseline in AI75 (%) of high-nitrate versus low-nitrate intervention on (A) Day 1 and (B) Day 7 in 27 healthy participants. Values are expressed as mean ± SEM. An intervention × time interaction was observed on Day 1 (p = 0.03, repeated measures ANOVA). *Significantly different from low-nitrate intervention as assessed by repeated measures ANOVA, p = 0.01.
Mentions: A significant treatment × time interaction was observed on Day 1 for AI75 (p = 0.03, two-way ANOVA). On Day 1, there was a reduction in AI75 following the high-nitrate intervention with a maximum effect of -5.72 ± 10.8% at 180 minutes relative to control (p = 0.01) and -6.54 ± 9.7% reduction relative to baseline (p = 0.002; Figure 1). Following 7 days of intervention, the high-nitrate intervention produced a comparable reduction on AI75 from baseline when compared to Day 1 (6.93 ± 8.7%, p < 0.001). However, on Day 7, the low-nitrate intervention produced a similar effect to the high-nitrate meal, with no differences between interventions (high vs. low-nitrate: -2.28 ± 12.5%, p = 0.35; Figure 1). A significant reduction of AI75 on Day 7 compared to Day 1 was observed in the low-nitrate intervention at 120 minutes (-4.55 ± 10.3%, p = 0.03), but not at 180 minutes (-3.83 ± 10.4%, p = 0.065; Table 2). The within subject coefficient of variation for AI75 was 16.6%, in line with recently reported values [10].

Bottom Line: However, the constituents responsible for this effect have not been well established.A postprandial reduction in augmentation index was observed at 180 min on high-nitrate compared to low-nitrate intervention (-6.54 ± 9.7% vs. -0.82 ± 8.0%, p = 0.01) on Day 1, and from baseline on Day 7 (-6.93 ± 8.7%, p < 0.001; high vs. low: -2.28 ± 12.5%, p = 0.35), suggesting that the nitrate intervention is not associated with the development of tolerance for at least 7 days of continued supplementation.High vs. low-nitrate intervention also reduced central systolic (-3.39 ± 5.6 mmHg, p = 0.004) and diastolic BP (-2.60 ± 5.8 mmHg, p = 0.028) and brachial systolic BP (-3.48 ± 7.4 mmHg, p = 0.022) at 180 min following 7-day supplementation only.

View Article: PubMed Central - PubMed

Affiliation: Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Toronto, ON M5B 1W8, Canada. ; Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.

ABSTRACT
Diets rich in fruits and vegetables reduce risk of adverse cardiovascular events. However, the constituents responsible for this effect have not been well established. Lately, the attention has been brought to vegetables with high nitrate content with evidence that this might represent a source of vasoprotective nitric oxide. We hypothesized that short-term consumption of spinach, a vegetable having high dietary nitrate content, can affect the arterial waveform indicative of arterial stiffness, as well as central and peripheral blood pressure (BP). Using a placebo-controlled, crossover design, 27 healthy participants were randomly assigned to receive either a high-nitrate (spinach; 845 mg nitrate/day) or low-nitrate soup (asparagus; 0.6 mg nitrate/day) for 7 days with a 1-week washout period. On days 1 and 7, profiles of augmentation index, central, and brachial BP were obtained over 180 min post-consumption in 4 fasted visits. A postprandial reduction in augmentation index was observed at 180 min on high-nitrate compared to low-nitrate intervention (-6.54 ± 9.7% vs. -0.82 ± 8.0%, p = 0.01) on Day 1, and from baseline on Day 7 (-6.93 ± 8.7%, p < 0.001; high vs. low: -2.28 ± 12.5%, p = 0.35), suggesting that the nitrate intervention is not associated with the development of tolerance for at least 7 days of continued supplementation. High vs. low-nitrate intervention also reduced central systolic (-3.39 ± 5.6 mmHg, p = 0.004) and diastolic BP (-2.60 ± 5.8 mmHg, p = 0.028) and brachial systolic BP (-3.48 ± 7.4 mmHg, p = 0.022) at 180 min following 7-day supplementation only. These findings suggest that dietary nitrate from spinach may contribute to beneficial hemodynamic effects of vegetable-rich diets and highlights the potential of developing a targeted dietary approach in the management of elevated BP.

No MeSH data available.


Related in: MedlinePlus