A Double-blind Placebo Controlled Study to Determine the Effect of Tea Consumption on Gut Microbiota Composition and Body-Iron Status
试验速览
- 阶段
- 不适用
- 入组人数
- 40
- 试验地点
- 1
- 主要终点
- Levels of faecal and urine metabolites of the individuals consuming tea/placebo during the 4 weeks intervention
研究概览
简要总结
Iron is an essential micronutrient for nearly all living organisms, including microbes. The adult human body contains approximately 3-5 g of iron (45-55 mg/kg of body weight in adult women and men, respectively). Iron-deficiency related anaemia (IDA) is a major public health problem that affects more than 2 billion people globally and this represents 24.8% of the world's population. According to World Health Organisation (WHO), iron deficiency is the most common cause of anaemia worldwide, with infants, children and women at higher risk, making it a global public health problem. Much iron deficiency is a result of poor iron dietary absorption since iron is poorly absorbed (~15%). Absorption inhibition factors (iron chelators) like phytate and tannins, found in tea and vegetables have been reported to act as potent iron uptake inhibitors. Despite its health benefits, tea-containing polyphenols (tannins) have been associated with reduction and disruption of iron absorption, acting as inhibitors of non-haem iron uptake, potentially resulting in poor iron status. However, most studies on the effect of tea on iron absorption are largely based on isotope-labelled single meal studies and animal studies. Iron is a requirement of many microorganisms, as such changes in iron availability can also have an impact on the gut microbiota. Long-term controlled human intervention studies to investigate the effect of tea on iron absorption and the effect on gut microbiota composition are scarce. In addition, the impact of dietary tannins on the gut microbiota is not understood. Thus, this proposed human intervention trial will investigate the combined effect of tea-tannins on iron status, inflammation and gut microbiota composition. This will be the first study to consider this combination of factors.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Screening
- 盲法
- Triple (Participant, Investigator, Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 60 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Age: 18-60 years
- •Gender: Male or Female
- •Volunteers agree to sign an informal written consent form
- •General good health
- •Normal haemoglobin and serum ferritin levels
排除标准
- •Regular tea drinkers
- •Use of antibiotics, prebiotics or probiotics (in food products or as supplements), laxatives, anti-spasmodic, anti-diarrhoea drugs, (e.g. Orlistat, Lactulose) in the last 4 weeks prior to, or during the study period.
- •Use of any iron supplement in the last 6 months prior to the study period.
- •If participants have received bowel preparation for investigative procedures in the 4 weeks prior to the study.
- •Surgical resection of any part of the bowel.
- •If you have any chronic gut disorder/disease, such as IBS, IBD, etc. or other conditions that might affect the gut environment, e.g. coeliac disease. If participants are taking any medication that could affect the iron absorption (e.g. lansoprazole, omeprazole). Those with gluten allergies (e.g. Celiac disease) must be excluded as the placebo may contain gluten
- •If participants are pregnant or are lactating.
- •If participants have a BMI > 30 kg/m
- •Severe allergy or any history of severe abnormal drug reaction, drug or alcohol abuse
研究组 & 干预措施
Black tea group
Volunteers meeting inclusion/exclusion criteria will be given an appropriate number of black tea samples twice a day with main meals for the 4 weeks of the treatment.
干预措施: Black tea (Dietary Supplement)
Placebo group
Volunteers meeting inclusion/exclusion criteria will be given an appropriate number of placebo tea samples twice a day with main meals for the 4 weeks of the treatment.
干预措施: Placebo (Dietary Supplement)
结局指标
主要结局
Levels of faecal and urine metabolites of the individuals consuming tea/placebo during the 4 weeks intervention
时间窗: 4 weeks intervention
Changes of metabolic profile during the intervention will be estimated in faecal and urine samples using Nuclear Magnetic Resonance (NMR)
Levels of ferritin (ng/mL) as body-iron status indicators of the individuals consuming tea/placebo during the 4 weeks intervention
时间窗: 4 weeks intervention
Ferritin will be monitored through blood samples collected during study visits.
Composition and diversity of the faecal microbiota of the individuals consuming tea/placebo during the 4 weeks intervention
时间窗: 4 weeks intervention
Changes in composition and diversity of faecal microbiota in response to black tea intervention assessed by next generation sequences NGS
Changes in the concentration (pg/mL) of inflammation markers in plasma of the individuals consuming tea/placebo using enzyme-linked immunosorbent assays (ELISAs)
时间窗: 4 weeks intervention
gut inflammation will be assessed by measuring concentration (pg/mL) of gut inflammatory markers as plasma intestinal fatty acid-binding protein and cytokines from plasma (e.g. IL-10, IL-6, TNFα). Samples will be analysed using enzyme-linked immunosorbent assays (ELISAs)
Changes in the concentration (mcg/g) of faecal calprotectin (gut inflammatory marker) during tea intervention using enzyme-linked immunosorbent assays (ELISAs)
时间窗: 4 weeks intervention
Gut inflammation will be assessed measuring concentration (mcg/g) of calprotectin. Increase in the levels of Calprotectin indicates the migration of neutrophils to the intestinal mucosa, which occurs during intestinal inflammation.
次要结局
- Assessment of stool consistency(4 weeks intervention)
- Assessment of gastrointestinal symptoms(4 weeks intervention)
研究者
Gemma Walton
Principle Investigator
University of Reading