Effects of Dietary Nitrate and Vitamin C Co-supplementation on Blood Pressure and Endothelial Function in Overweight Individuals
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 15
- 试验地点
- 1
- 主要终点
- Cardiac function
研究概览
简要总结
The investigators have shown in two short-term studies in healthy, young participants that the combined supplementation of inorganic nitrate with vitamin C has beneficial effects on blood pressure and blood vessel wall stiffness. However, the effects of the combined supplementation have not been tested in individuals at greater cardiovascular disease risk. The investigators would like to show whether inorganic nitrate and vitamin C will produce greater effects on blood pressure and endothelial function when compared to inorganic nitrate alone versus the placebo treatment in people at greater risk of cardiovascular disease.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 50 Years 至 75 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Participant is willing and able to give informed consent for participation in the study.
- •Participant is willing and able to comply with the requirements of the study protocol.
- •Non-smoking men and women.
- •Aged between 50-75 years.
- •Overweight and obese (BMI: over 25.0 kg/m2).
排除标准
- •Having taken part in a research study in the last 3 months involving invasive procedures or an inconvenience allowance.
- •Vegetarian.
- •Resting systolic blood pressure greater than 160 mmHg; diastolic blood pressure greater than 100 mmHg.
- •Active cancer and any diagnosis of malignant cancer in the last 5 years.
- •Excessive alcohol intake (>21 units per week).
- •Allergy or intolerance to the intervention food (Beetroot juice).
- •Diagnosis of chronic or acute metabolic and inflammatory conditions that may interfere with the study outcomes.
- •Major surgical operations.
- •Use of prescribed psychiatric drugs (antidepressants, sedatives, antipsychotics), diuretics, organic nitrates, statins and proton pump inhibitors.
- •Use of prescribed hormonal therapies (oestrogens, thyroxin, and progesterone), anti-hypertensive (Calcium++ channel blockers, beta-blockers, and angiotensin-converting-enzyme (ACE) inhibitors), only if the prescription had started, or the dose had been started/changed, in the previous three months.
- •Non-prescribed dietary supplements if not stopped at least for 2 weeks before starting the trial.
- •Use of the mouthwash during the study was not allowed as it interferes with the conversion of oral nitrate into nitrite.
研究组 & 干预措施
Placebo
Placebo beetroot juice and tablet
干预措施: Nitrate-depleted beetroot juice plus placebo tablet (Dietary Supplement)
Beetroot juice + Vitamin C
Beetroot juice and Vitamin C
干预措施: Beetroot juice plus vitamin C tablet (Dietary Supplement)
Beetroot juice + placebo
Beetroot juice + placebo tablet
干预措施: Beetroot juice plus placebo tablet (Dietary Supplement)
结局指标
主要结局
Cardiac function
时间窗: Pre and post 3 days of supplementation
Resting cardiac function using a non-invasive methodology (Finometer)
Blood pressure
时间窗: Pre, 24 hours, 48 hours and 72 hours after supplementation
Resting diastolic and systolic blood pressure using portable automated monitor
Cardiac function
时间窗: Pre and post 3 days of supplementation
Resting cardiac function using a non-invasive methodology (Finometer)
次要结局
- Flow-mediated dilation(Pre and post 3 days of supplementation)
- Saliva nitrate concentration(Pre and post 3 days supplementation)
- Urinary nitrate concentration(Pre and post 3 days supplementation)
- Saliva nitrite concentration(Pre and post 3 days supplementation)
- Urine vitamin C concentration(Pre and post 3 days supplementation)
- Urine 8-isoprastane concentration(Pre and post 3 days supplementation)
研究者
Kostas Tsintzas
Professor of Human Physiology
University of Nottingham