Iron Absorption, Zinc Absorption
Conditions
Keywords
zinc, iron, absorption, phytate, polyphenols, beans
Brief summary
Fifteen female study participants will be enrolled in a randomized crossover study to measure fractional and total zinc and iron absorption from four common bean (Phaseolus vulgaris) varieties with varying phytate and polyphenolic contents. Phytate, the storage form of phosphorus in plants, and polyphenols, which contribute to the varied colors of common beans, are natural components of the beans and can reduce zinc and iron bioavailability from these foods.
Detailed description
Each participant will attend a total of 10 study visits. The first visit will be a screening visit to determine eligibility, and will include the administration of health history and food frequency questionnaires, and a urine pregnancy test. Participant will also be given a ASA24 24-hour dietary recall at visit 1 to return at visit 2. All subsequent visits (2 through 10) will begin with a blood sample (15 mL, or 1 tablespoon, after a 12 hour overnight fast). Visit 2 will establish the baseline distribution of naturally occurring zinc and iron isotopes in the blood, and will include the administration of water enriched in zinc of a specific naturally-occurring isotopic mass (zinc-68, 4 mg). Visits 2-5 will be on consecutive days, while Visit 6 will be 14 days following Visit 5. Visits 3 and 4 will include breakfast, lunch, and dinner, each containing a small serving of beans that are enriched in specific isotopic masses of iron and zinc (2 mg each of zinc-67 and iron-57, or 1 mg each of zinc-70 and iron-58). Visits 5 and 6 are for blood sampling, to measure the zinc in blood plasma (Visit 5) and the iron that has reached a 14-day equilibrium in red blood cells (Visit 6). Participants will also be given a ASA24 24-hour dietary recall at visit 6 to return at visit 7. Visits 6-9 will be on consecutive days, starting 28 days (the approximate length of one menstrual cycle) after Visit 3, while Visit 10 will be 14 days following Visit 9. The 28-day timing is needed to minimize the potential influence of natural variation in circulating hormones, on zinc metabolism. A second urine pregnancy test will be administered on Visit 10, to detect any pregnancies that would have occurred at the time of the study meals 2 weeks prior or earlier. Participants will also be given a ASA24 dietary recall at visit 9 to return at visit 10.
Interventions
OTHERSER 118
Bean High in Phytic Acid and High in Inhibitory Polyphenols
OTHERLMP 1001
Bean Low in Phytic Acid and High in Inhibitory Polyphenols
OTHERLPA 586
Bean Low in Phytic Acid and Low in Inhibitory Polyphenols
OTHERKAT B1
Bean High in Phytic Acid and Low in Inhibitory Polyphenols
Sponsors
University of California, Davis
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Masking description
Study participants will be masked to the type of bean that they will be receiving.
Intervention model description
A four arm multi-tracer non-randomized crossover design
Eligibility
Sex/Gender
FEMALE
Age
19 Years to 24 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy eumenorrheic (regular monthly menstrual cycles of 25-30-days in length) * BMI 18.5 - 30 kg/m2 * Regular consumer of beans, i.e. ≥ 4 servings per month * Usual iron intake estimated by Food Frequency Questionnaire to be less than the Recommended Daily Allowance (RDA) of 18 mg/d (8) * Subject is willing and able to comply with the study protocols. * Subject is willing to participate in all study procedures.
Exclusion criteria
* Dislike or allergy to beans * Self-reported current or recent pregnancy (within the past 12 months) * Self-reported recent termination of pregnancy (3 months if abortion in 1st or 2nd trimester, or 12 months if in 3rd trimester) * Self-reported plans to become pregnant during the study period * Self-reported cancer * Self-reported surgery without the past 12 months * Currently taking prescription drugs, other than for contraception, or any nutritional supplements * Any daily iron supplementation within the past 12 months. * Currently breastfeeding * Any medical conditions affecting iron or zinc metabolism (such as hemochromatosis or sickle cell disease)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fractional Zinc absorption | 24 hours after first intake | amount of zinc absorbed and circulating in blood |
| Fractional Iron absorption | 24 hours after first intake | amount of iron absorbed and circulating in the blood |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Total Zinc absorption | 24 hours after first intake | total amount of zinc absorbed from meals |
| Total Iron absorption | 24 hours after first intake | total amount of iron absorbed from meals |
Countries
United States
Contacts
CONTACTRoberta R Holt, PhD
PRINCIPAL_INVESTIGATORAndrew G Hall, PhD
University of California, Davis
Outcome results
None listed