Tea Consumption and Iron Bioavailability in Women Using a Stable Isotope
Condition: Anemia, Iron-Deficiency
MeSH terms: Anemia, Iron-Deficiency; Iron Deficiencies
Study type: Interventional

Summary: 
      The purpose of this study is to investigate the inhibition effect of tea consumption on non
      haem iron absorption with the use of an iron tracer. The study also aims to assess the effect
      of time variability of tea consumption on non haem iron absorption from a typical western
      breakfast.
    

Detailed description: 
      This is a non randomised controlled trial in 12 healthy participants over a period of 56
      days. The study will investigate the inhibition effect of tea consumption on non haem iron
      absorption with the use of a stable iron isotope (Fe57) tracer. The study also aims to assess
      the effect of time variability of tea consumption on non haem iron absorption from a typical
      western breakfast.There is evidence of lower iron absorption when a meal is given with tea,
      compared to water. There is also evidence from previous studies that the inhibition effect is
      higher when tea is consumed simultaneously with a meal, compared to in between meals.
      However, there are limited number of human studies investigating iron absorption and time
      interval, particularly in the UK. The study aims to recruit 12 healthy participants. The test
      meals will be given together with black tea labelled with iron tracer, at various time
      intervals which includes together and after the meals. Test meal given with water will be
      used as a control. Blood samples will be collected 14 days post dosage for each of the meals.
      The study will take place at University of Chester, and participants will attend 5 clinics
      during the 56 day study. Prior to the start of study, participants will complete a 3 day food
      diary, where they will be given instructions by the researcher. In each clinic, weight and
      height will be measured, followed by a fasted blood sample and the administration of test
      meals.

      PROJECT HYPOTHESES H1: There is a significant difference in non haem iron absorption from a
      typical western breakfast with tea consumption compared to without tea consumption H0:There
      is no significant difference in non haem iron absorption from a typical western breakfast
      with tea consumption compared to without tea consumption H1: Iron absorption will be lower
      when tea is consumed simultaneously with meals compared to when it is consumed in between
      meals H0: The iron absorption will not be lower when tea is consumed simultaneously with
      meals compared to when is consumed in between meals H1: There is an inverse correlation
      between tea consumption and iron status parameters H0: There is no inverse correlation
      between tea consumption and iron status parameters

      There are several parameters which will be measured in this study. Height and weight will be
      measured using methods outlined in the Manual of Dietetic Practice using validated equipment
      (weighing scales and stadiometer). These will be measured by the student researcher at
      baseline and at each clinic (Clinic 1 to 5). Dietary intakes will be measured based on the
      data gathered in the 3 days food diary completed by the participants prior to Clinic 1 and 5.
      Additionally, blood samples will be taken by student researcher at each clinic. The analysis
      will be carried out in the Clinical Laboratories and Phlebotomy Room within the Department of
      Clinical Sciences and Nutrition (University of Chester), utilising the equipment and the
      clinical space where the participants will have to report during the administration of the
      meals with iron tracer. Test meals will be prepared in the food skills kitchen within the
      department. Analysis of blood samples will also be carried out in Clinical Sciences
      laboratories using relevant methodologies, including ELISA assays, bioanalysers and mass
      spectrometry. After the administration of meals labelled with iron tracers, all the blood
      samples will be stored at 80 Celsius in the laboratory until further analysis.

      RECRUITMENT PROCESS The sampling will be carried out at the University of Chester.
      Posters/leaflets and letter/emails will be used as a medium of advertisement to the targeted
      group, especially to staff and students. The potential participants who require further
      information will be given participant information sheet which explains the procedure of the
      study.

      STUDY PROCEDURE Clinic visits will take place between 0800 to 1000 (lasting for approximately
      45 minutes) at the Clinical Sciences & Nutrition laboratory, University of Chester. 5 clinics
      are required, with a time interval of 14 days between clinics to allow the incorporation of
      the stable iron isotope (Fe57) tracer into the blood. During each clinic, participants will
      be given test meals labelled with iron tracer and tea, and no food or drink will be allowed
      for the next 3 to 4 hours. All the containers used to administer the test meals will be
      washed with ultrapure water to make sure complete consumption of both test meals and iron
      tracer. Participants will attend each clinic after an overnight fast (10 hours), and 30 ml
      blood samples (6 teaspoons) will be collected at each clinic. All the clinic details are
      given below.

      Clinic 1 (Day 0): Participants will complete a screening questionnaire, followed by physical
      measurements of height and weight. If they satisfy the inclusion criteria, they will be
      invited to participate in the study and be asked to sign an informed consent form.
      Participants will be asked about their food consumption over the previous 24 hours and will
      be required to complete 3 day food diary to reflect habitual intake. Participants will be
      given an explanation on how to record the dietary intake. Height and weight will be measured,
      followed by a baseline blood sample. This will be followed by consumption of the control test
      meal.

      Clinic 2 (Day 14): Measurement of height and weight followed by a baseline blood sample and
      24 hour food recall will be carried out. This will be followed by consumption of the test
      meal II with tea given simultaneously with the test meal.

      Clinic 3 (Day 28): Measurement of height and weight followed by a baseline blood sample and
      24 hour food recall will be carried out . This will be followed by consumption of the test
      meal III with tea given 1 hour after the test meal.

      Clinic 4 (Day 42): Measurement of height and weight followed by a baseline blood sample and
      24 hour food recall will be carried out . This will be followed by consumption of reference
      dose iron.

      Clinic 5(Day 56): Prior to the completion of the study, participants will be given another 3
      day food diary which has to be completed before the clinic for another assessment of dietary
      intake. Measurement of height and weight followed by a final blood sample drawn to measure
      the incorporation of iron from the reference dose and 24 hour food recall.

      DATA-PLAN

      Sample size determination and justification :

      Sample size was estimated using iron absorption data (mean ± S.D) from a study by Derman et
      al. (1977) in which they reported iron absorption (%) of 6.7 ± 6.2 when the test meals were
      administered with tea and 34.0 ± 23.0 when the test meals were administered without tea. With
      an effect size of 1.324, the total sample size required in the proposed study is 10. Taking
      into account a 20% drop out rate, the total sample size required to demonstrate a significant
      difference in iron absorption between consumption of meal with and without tea is 12 (Power =
      0.95).

      Data Analysis :

      All statistical analyses will be conducted by the research student with International
      Business Machines (IBM)® Statistical Package for the Social Sciences (SPSS)® Statistic Data
      Editor Software (Version 21). Values for iron absorption and meal ratios will be expressed as
      geometric means and standard deviations. Iron absorption values (in percentage) will be
      logarithmically transformed for the purpose of analyses and will then be retransformed to
      recover the original units (Hurrell et al., 1999). Assuming that the data is normally
      distributed after performing normality test (Shapiro Wilks), paired student t tests will be
      conducted (i) to compare the iron absorption from each pair of meals and (ii) to obtain the
      absorption ratios in the test meals in relative to the reference dose without meal. Pearson's
      correlation test will be performed to investigate the relationship between tea drinking and
      iron status biomarkers. A nonparametric approach will be adopted if the data is not normally
      distributed for all analyses. Differences will be considered significant with a p value <
      0.05.
    

Intervention name(s): Test meal I (given with water); Test meal II (simultaneously with tea); Test meal III (1 hour after test meal); Reference iron dose
Intervention type(s): Other; Other; Other; Other
Intervention description(s): 4 mg of the iron stable isotope, in a form of ferrous sulphate solution, extrinsically labelled in the test meal administered in the study, enrichment in the system will take approximately 14 days post dosing; 4 mg of the iron stable isotope, in a form of ferrous sulphate solution, extrinsically labelled in the test meal administered in the study, enrichment in the system will take approximately 14 days post dosing; 4 mg of the iron stable isotope, in a form of ferrous sulphate solution, extrinsically labelled in the test meal administered in the study, enrichment in the system will take approximately 14 days post dosing; 3 mg of the iron stable isotope, in a form of ferrous sulphate solution, extrinsically labelled and administered in the study, enrichment in the system will take approximately 14 days post dosing
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Anemia, Iron-Deficiency; Iron, Bioavailability; Hepcidins; Intestinal, Absorption; Isotope Labeling, Stable