Effect of Coca-Cola on Iron Absorption

Quadram Institute Bioscience

Status: Completed

Conditions: Iron Deficiency

Treatments: Drug: Coca, Cola, Diet Coke

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT00474500

IFR13/2006

Details and patient eligibility

About

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.

Full 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.

Enrollment: 16 patients

Sex: Female

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

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