Publications by authors named "Alex H Liu"

Background: Higher cruciferous vegetable intake is associated with lower cardiovascular disease risk in observational studies. The pathways involved remain uncertain. We aimed to determine whether cruciferous vegetable intake (active) lowers 24-h brachial systolic blood pressure (SBP; primary outcome) compared to root and squash vegetables (control) in Australian adults with mildly elevated BP (SBP 120-160 mmHg inclusive).

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Article Synopsis
  • Dietary nitrate from vegetables, like beetroot, may help reduce inflammation and improve immune response, but its effects on those with hypertension are unclear.
  • A study involving 27 people tested the impact of nitrate-rich beetroot juice versus a placebo over one week on inflammatory markers in individuals with treated hypertension.
  • The results showed no significant changes in inflammatory markers, although participants experienced notable increases in nitrate and nitrite levels in saliva, plasma, and urine after consuming beetroot juice.
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Scope: Nitrate and nitrite are approved food additives in some animal-based food products. However, nitrate and nitrite in foods are strictly regulated due to health concerns over methaemoglobinaemia and the potential formation of carcinogenic nitrosamines. In contrast, plants (like leafy vegetables) naturally accumulate nitrate ions; a growing body of research reveals beneficial metabolic effects of nitrate via its endogenous conversion to nitric oxide.

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Purpose: Short-term trials indicate inorganic nitrate and nitrate-rich vegetables may have vascular health benefits. However, few observational studies have explored the relationship between nitrate intake and long-term cardiovascular disease (CVD) outcomes. The primary aim of this study was to investigate the association of nitrate intake from vegetables with CVD mortality in a sample of older Australians.

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Background: Dietary nitrate is an important source of nitric oxide (NO), a molecule critical for cardiovascular health. Nitrate is sequentially reduced to NO through an enterosalivary nitrate-nitrite-NO pathway that involves the oral microbiome. This pathway is considered an important adjunct pathway to the classical l-arginine-NO synthase pathway.

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Vegetable derived nitrate is now recognised as an important bioactive phytochemical with cardioprotective properties. Nitrate, through the recently described enterosalivary nitrate-nitrite-nitric oxide (NO) pathway, increases NO, a molecule pivotal for cardiovascular health. Clinical trials have observed that dietary nitrate has similar effects to NO when supplied exogenously.

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Background: Dietary nitrate, which is in green leafy vegetables and beetroot, decreases blood pressure through the enterosalivary nitrate-nitrite-nitric oxide pathway in healthy individuals. Whether similar effects would occur in individuals with treated hypertension and, therefore, at increased risk of cardiovascular disease is unclear.

Objective: We assessed whether increased dietary nitrate intake by using beetroot juice for 1 wk lowers blood pressure in treated hypertensive men and women.

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Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined.

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Background: Endothelial nitric oxide (NO) is fundamental to cardiovascular health. Dietary nitrate and nitrate from endothelial derived NO metabolism provides a significant contribution to the circulating NO pool through the nitrate-nitrite-NO pathway. A critical step in this pathway is the reduction of nitrate to nitrite by the oral microbiota.

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Evidence for a beneficial effect of dietary nitrate, through the nitrate-nitrite-NO pathway, on measures of cardiovascular function in healthy individuals is accumulating. It is less clear whether increased dietary nitrate intake from green leafy vegetables would have similar beneficial vascular effects in those at increased risk of developing hypertension. Our aim was to assess the effects of short-term regular consumption of increased nitrate from green leafy vegetables on blood pressure and arterial stiffness in individuals with high-normal blood pressure.

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An increase in nitrate intake can augment circulating nitrite and nitric oxide. This may lead to lower blood pressure and improved vascular function. Green leafy vegetables, such as spinach, are rich sources of nitrate.

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There is mounting evidence that specific dietary polyphenols can enhance vascular health by augmenting nitric oxide. Our aim was to investigate the acute effects of chlorogenic acid, an important dietary phenolic acid present in coffee (400 mg, equivalent to 2 cups of coffee), on nitric oxide status, endothelial function, and blood pressure. Healthy men and women (n = 23) were recruited to a randomized, double-blind, placebo-controlled, crossover trial.

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