Clinical trial NCT00474500: Effect of Coca-Cola on Iron Absorption
Official title: Effect of Coca-Cola on Iron Absorption
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Iron Deficiency
Keywords: Iron absorption
Coca-Cola
Lead sponsor: Quadram Institute Bioscience
Sponsor class: OTHER
Collaborators: name: University of East Anglia
name: The Coca-Cola Company
First posted: 2007-05-17
Enrollment: 16
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: The aim of this project is to measure the effect of Coca-Cola and Diet Coke, relative to mineral water, on non-haem iron absorption. The results from this study will quantify any enhancing effect of Coca-Cola or Diet Coke on non-haem iron absorption and will be of use to the Coca-Cola Company and the scientific and nutrition community in evaluating the nutritional value of these products.

Detailed description: Previous studies have suggested that Coca-Cola may enhance absorption of non-haem iron. A randomized cross-over trial will be undertaken to compare the absorption of iron added to a pizza meal consumed with either Coca-Cola, Diet Coke or mineral water. Pizza containing added iron, labelled with an iron stable isotope (Fe-58), will be consumed for lunch on two consecutive days with either a Coca-Cola, Diet Coke or mineral water drink. Iron absorption from the pizza will be determined using the erythrocyte incorporation technique.

A baseline blood sample will be taken prior to consuming the first test meal (pizza + drink 1) and after approximately 15 days, a second fasting blood sample will be taken prior to consumption of a second set of test meals (pizza + drink 2). Iron isotope enrichment of the blood sample will be used as a baseline for the second set of test meals and to calculate absorption from the first set of test meals. A third blood sample will be taken after approximately 30 days and the iron isotope enrichment will be used as a baseline for the third set of test meals (pizza + drink 3) and to determine absorption from the second set of test meals. At about 45 days a final blood sample will be taken to determine absorption from the third set of test meals. Iron absorption will be calculated from the isotopic enrichment in blood, assuming that 80% of absorbed iron is incorporated into red blood cells. Absorption of iron consumed with Coca-Cola and Diet Coke will be compared with iron absorption when consumed with mineral water. The order in which the volunteers will be given the drinks will be randomised.

Eligibility criteria: Inclusion Criteria:

* Women
* Age \> 18 and \< 65

Exclusion Criteria:

* Men
* Age \< 18 or \> 65
* BMI \<18.5 or \> 35
* Serum ferritin value of \<12 or \>50µg/L (±10% to allow for day to day and analytical variation)
* Volunteers will be excluded if they are found to have depressed or elevated blood pressure measurements (\<90/50 or \<95/55 if symptomatic or \>160/100)
* Diagnosed with a long-term illness requiring active treatment, e.g. diabetes, cancer, cardiovascular disease.
* Gastrointestinal disease (excluding hiatus hernia unless symptomatic or study intervention/procedure is contraindicated)
* Regular prescribed medication that may interfere with iron metabolism
* Regular use of antacids and laxatives (at least once a week)
* Women who are pregnant or less than 12 months since giving birth
* Women breast feeding
* Vitamin supplements with or without minerals if taken more than once a week, and unwillingness to discontinue occasional use for the duration of study
* Unwillingness to discontinue use of herbal supplements for the duration of study
* Use of antibiotics within four weeks prior to study start
* Parallel participation in another study which involves dietary interventions or sampling of blood that may increase the volume taken above 500ml in a 4-month period
* Asthma requiring treatment within the last two years
* Results of clinical screening which indicate, or are judged by the HNU Medical Advisor to be indicative of a health problem which could compromise the well-being of the volunteer if they participated or which would affect the study data.
* Allergy to any of the ingredients in the test meals

Primary outcomes:
measure: Non-haem iron absorption
timeFrame: 1 year
Secondary outcomes:
Other outcomes:
Locations:
city: Norwich
country: United Kingdom
facility: Institute of Food Research
state: Norfolk
Study officials:
affiliation: University of East Anglia
name: Susan J Fairweather-Tait
role: PRINCIPAL_INVESTIGATOR
References:
citation: Collings R, Fairweather-Tait SJ, Dainty JR, Roe MA. Low-pH cola beverages do not affect women's iron absorption from a vegetarian meal. J Nutr. 2011 May;141(5):805-8. doi: 10.3945/jn.110.136507. Epub 2011 Mar 9.