Gilchrist Mark, Winyard Paul G, Fulford Jon, Anning Christine, Shore Angela C, Benjamin Nigel
NIHR Exeter Clinical Research Facility and Institute of Biomedical and Clinical Science, University of Exeter Medical School (Previously Peninsula College of Medicine and Dentistry), University of Exeter, Exeter EX2 5AX, UK.
NIHR Exeter Clinical Research Facility and Institute of Biomedical and Clinical Science, University of Exeter Medical School (Previously Peninsula College of Medicine and Dentistry), University of Exeter, Exeter EX2 5AX, UK.
Nitric Oxide. 2014 Aug 31;40:67-74. doi: 10.1016/j.niox.2014.05.003. Epub 2014 May 21.
In this substudy of the effect of dietary nitrate on blood pressure, endothelial function, and insulin sensitivity in type 2 diabetes, we report the development of a novel nitrate depleted beetroot juice for use clinical trials and determine if dietary nitrate supplementation improved cognitive function in patients with type 2 diabetes mellitus.
Beetroot juice was treated with the anion exchange resin Purolite A520e. UV-vis-spectrophotometry, and a blind taste test were performed along with determination of sugar content, measurement of ascorbate and dehydroascorbate, the ionic composition of juice and Proton NMR. Subsequently, 27 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 beetroot juice (nitrate content 7.5 mmol per 250 ml) or placebo (nitrate depleted beetroot juice nitrate content 0.002 mmol per 250 ml). At the end of each 2 week supplementation period cognitive function was assessed using E-prime, E-Studio software with 5 separate tests being performed. The tests utilised in the present study have been adapted from the Cambridge Neuropsychological Test Automated Battery (CANTAB).
The differences in the UV-vis spectra were comparable to the natural variation found in differing cultivars. There were no discernable differences in taste, sugar content, or Proton NMR. Ascorbate and dehydroascorbate were undetectable in either juice. After 2 weeks of beetroot juice simple reaction time was significantly quicker in the active arm at 327±40 ms versus 341.8±52.7 ms in the placebo arm, mean difference 13.9±25.6 ms (95% CI 3.8-24.0 ms), p=0.009. No other measures of cognitive function differed between treatment arms.
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.
在这项关于膳食硝酸盐对2型糖尿病患者血压、内皮功能和胰岛素敏感性影响的子研究中，我们报告了一种用于临床试验的新型硝酸盐耗尽甜菜根汁的研发情况，并确定膳食硝酸盐补充剂是否能改善2型糖尿病患者的认知功能。
用阴离子交换树脂Purolite A520e处理甜菜根汁。进行紫外可见分光光度法和盲味测试，同时测定糖含量、抗坏血酸和脱氢抗坏血酸含量、果汁的离子组成以及质子核磁共振。随后，招募了27名年龄为67.2±4.9岁（18名男性）的患者进行双盲、随机、安慰剂对照交叉试验。参与者被随机分为两组，分别按顺序开始饮用甜菜根汁（每250毫升硝酸盐含量7.5毫摩尔）或安慰剂（硝酸盐耗尽甜菜根汁，每250毫升硝酸盐含量0.002毫摩尔）。在每个为期2周的补充期结束时，使用E-prime、E-Studio软件进行认知功能评估，共进行5项独立测试。本研究中使用的测试是根据剑桥神经心理测试自动成套系统（CANTAB）改编的。
紫外可见光谱的差异与不同品种中发现的自然变异相当。在味道、糖含量或质子核磁共振方面没有明显差异。两种果汁中均未检测到抗坏血酸和脱氢抗坏血酸。饮用甜菜根汁2周后，试验组的简单反应时间明显更快，为327±40毫秒，而安慰剂组为341.8±52.7毫秒，平均差异为13.9±25.6毫秒（95%可信区间3.8 - 24.0毫秒），p = 0.009。治疗组之间的其他认知功能指标没有差异。
我们研发了一种有效的安慰剂甜菜根汁，用于膳食硝酸盐补充试验。每天补充7.5毫摩尔硝酸盐，为期2周，可使2型糖尿病患者的简单反应时间显著改善。
