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Disorder of Vitamin B12NCT00235573

Evaluation of Holotranscobalamin as an Indicator of Vitamin B12 Absorption

A study testing Vitamin B12 in people with Disorder of Vitamin B12, run by University of Florida at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

Vitamin B12 is an essential nutrient that the body needs for cells to divide and function normally. Individuals may develop a deficiency of vitamin B12 by either limiting the amount in the diet or by decreased vitamin B12 intake into the body (absorption). Keeping adequate B12 blood levels is important for health. Read more about this study

Who is it for?
Ages 18 to 49 yearsHealthy volunteers can take part
Conditions the study is for
Disorder of Vitamin B12
What is being tested?
Vitamin B12
Could I receive a placebo?
No, everyone receives an active treatment
How many people
21 participants
Where
1 siteUnited States
Study dates
Oct 2005to Nov 2005
Phase
Interventional
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 49 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • No vitamin B12-containing supplement use within past year
  • No vitamin B12 injections within past year
  • No use of tobacco products
  • No chronic use of prescription medications except oral contraceptives
  • No history of chronic disease (e.g., pernicious anemia, cancer, diabetes, renal disease, hypertension, neurological abnormalities, gastrointestinal disorders)
  • BMI between 18.5-29.9
Show all 10Show fewer
  • General Chemistry Blood Tests (all values within or near normal range; hemoglobin if female ≥ 11.0 g/dL; if male ≥ 12 g/dL)
  • B12 status (Serum B12 ≥ 444 pmol/L)
  • Capable of understanding the informed consent form
  • Agrees to comply with protocol requirements

Who cannot join

  • History of pernicious anemia, cancer, diabetes, renal disease, hypertension, heart disease, neurological abnormalities, gastrointestinal disorders, lung disease, hepatic disease, hematologic, or other metabolic diseases that, in the opinion of the Co-Principal Investigators, would affect safety or compliance
  • Vitamin B12 supplement use or injections within past year
  • Pregnant or breast feeding
  • Has BMI <18.5 or >29.9
  • Has donated or lost a significant volume (>450 mL) of blood or plasma within 30 days of the study
  • General chemistry lab values outside of ranges
Show all 11Show fewer
  • Serum B12 outside of range listed above
  • Use of tobacco products
  • Chronic use of prescription medications except oral contraceptives
  • Does not understand the informed consent form
  • Does not agree to comply with protocol requirements

Trial locations and contacts

1 site in 1 country.

United States1 site
  • General Clinical Research Center, Shands Hospital, University of Florida

    Gainesville, Florida, 32610-0322

Other trials in United States

About this study

Vitamin B12 is an essential nutrient that the body needs for cells to divide and function normally. Individuals may develop a deficiency of vitamin B12 by either limiting the amount in the diet or by decreased vitamin B12 intake into the body (absorption). Keeping adequate B12 blood levels is important for health. Vitamin B12 deficiency may increase one's risk for developing anemia and can even lead to neurological problems and paralysis if the deficiency is severe and lasts a long time. It is very important for doctors to have accurate tests to determine if people are absorbing vitamin B12 normally so that treatment can be started before severe clinical problems occur.

The purpose of this research is to provide new information that may help scientists develop a better method to test for problems with absorbing vitamin B12. In this study, changes in the amounts of vitamin B12 bound to protein (transcobalamin) in the blood will be measured after doses of vitamin B12 are taken. If the amounts of this vitamin B12-protein complex (called holo-transcobalamin) change in response to taking a vitamin B12 supplement in normal individuals, it may be possible to use this information to develop a new sensitive test to identify individuals who have problems absorbing vitamin B12. This new vitamin B12 absorption test may be a better clinical test for vitamin B12 absorption than those now available for doctors to use.

Read the detailed description

Part I Screening: Individuals who meet initial screening criteria will be scheduled to have fasting blood samples drawn in the General Clinical Research Center (GCRC). All participants will sign informed consent forms approved by the UF Institutional Review Board prior to the initiation of this part of the study. Subjects' heights and weights will be measured and subjects will be asked to complete a medical history questionnaire. Blood analyses will include serum B12, blood chemistry, and hematological indices. Females will be given a pregnancy test. Subjects eligible for Part II of the study (Intervention) will have serum B12 concentrations that are ≥444 pmol/L; will be non-anemic; and will have normal general blood chemistry (all values within or near the normal range), and no history of chronic disease (e.g., pernicious anemia, cancer, diabetes, renal disease, hypertension, neurological abnormalities, gastrointestinal disorders). Any subject with deficient (<148 pmol/L) serum B12 concentration [18] will not be eligible for participation and will be instructed to see their personal physician for complete follow-up and treatment.

Part II Intervention: Changes in B12 status assessment indicators in response to B12 supplementation will be evaluated.

Subjects will come to the GCRC the night before (Day 1) the intervention protocol. The next morning (Day 1) following an overnight fast, an indwelling catheter will be inserted from which repeated blood samples will be drawn throughout Day 1. A baseline fasting blood sample (#1) will be drawn. Subjects will then consume a light breakfast (including 1 piece of bread and 8 oz of orange juice) and will take a 9 ug dose of B12 (Dose 1). Thirty minutes after completion of the meal and consumption of the B12 supplement, a second blood sample (#2) will be drawn. Five subsequent hourly blood samples (# 3-7) will be drawn. After the 7th blood sample the subjects will consume one piece of bread and 8 ounces of orange juice and will take a second 9 ug dose of B12 (Dose 2) and have a blood sample (#8) drawn 30 minutes after consumption of the meal and the B12 dose. Five subsequent hourly blood samples (#9-13) will be drawn. The subjects will then consume one piece of bread and 8 ounces of orange juice and take a 9 ug dose of B12 (Dose 3). Another blood sample (#14) will be drawn 30 minutes after the meal and the B12 dose. One hour later, a final (Day 1) blood sample (#15) will be drawn followed by removal of the catheter. In addition to the bread and juice consumed with each B12 supplement, subjects will receive a mid-morning snack 2 hours after Dose 1 of the B12 supplement, lunch 3.5 hrs after Dose 1 of the B12 supplement, dinner at 4 hours after Dose 2 of the B12 supplement, and an evening snack at 3 hours after Dose 3. Low B12-containing foods will be provided in the GCRC. Water and non-caffeinated, non-caloric beverages will be allowed ad libitum.

The subjects will remain in the GCRC overnight and a fasting blood sample (#16) will be drawn in the morning on Day 2. On Day 2 participants will be provided breakfast following the blood draw, after which they will be free to leave the GCRC. Subjects will be provided with take-away meals and snacks (lunch, dinner, snacks) consisting of low-B12 containing foods.

Subjects will be instructed to return on the morning of Day 3 at which time they will have one am fasting blood sample (#17) drawn and will be provided with breakfast before they leave the GCRC. All overnight fasts will be from 10 pm the previous night. The following B12 indicators will be measured at each blood draw (a) holo-TC; (b) total-TC; (c) holo-HC and total HC; (d) serum B12; and (e) plasma albumin. Additional B12 status indicators (e.g. homocysteine, methylmalonic acid, RBC B12) will be measured at select blood draw intervals. A baseline folate analysis will be done.

Being tested
Vitamin B12
Keywords
Vitamin B12 absorption, Holo-transcobalamin

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Vitamin B12Dietary supplement

    After taking a fasting blood sample, all subjects were given a light breakfast plus 9 micrograms of vitamin B12. Two more doses of vitamin B12, 9 micrograms each, were administered 6 hours apart.

Study groups in NCT00235573
Study groupRoleWhat they receive
Vitamin B12 supplementExperimentalAfter taking a fasting blood sample, all subjects were given a light breakfast plus 9 micrograms of vitamin B12. Two more doses of vitamin B12 were administered 6 hours apart.
Receives: Dietary Supplement: Vitamin B12

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Holo-transcobalamin

    Holo-TC is a vitamin B12 carrier protein. Only vitamin B12 bound to holo-TC can be taken up by cells. Changes in holo-TC after an oral dose of vitamin B12 may provide a clinical test to assess vitamin B12 absorption. The change in holo-transcobalamin (holo-TC) from baseline was measured at timed intervals in response to supplemental vitamin B12 and compared to baseline. The purpose was to ascertain the time point at which holo-TC reaches the maximum concentration in the blood following a dose of vitamin B12 in subjects without defects in vitamin B12 absorption.

    Measured: Holo-transcobalamin measured at 24 hours after baseline

Secondary outcomes (1)
  1. Total Transcobalamin Measured at Intervals From Baseline to 48 Hours.

    Measured: Baseline through 48 hours at intervals of 0, 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, 6, 7, 8, 9, 10, 11, 11.5, 12.5, 24, 48

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted10 Oct 2005 (estimated)
  2. Study startOct 2005
  3. Primary completionNov 2005
  4. Study completionNov 2005

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Diagnosis
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
21 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT00235573
Sponsor's protocol ID
433-2005
Other IDs
7591, M01RR000082
Status last verified
Dec 2011
First submitted
6 Oct 2005
Last updated
22 Dec 2011
Data monitoring committee
No

Publications

  • von Castel-Dunwoody KM, Kauwell GP, Shelnutt KP, Vaughn JD, Griffin ER, Maneval DR, Theriaque DW, Bailey LB. Transcobalamin 776C->G polymorphism negatively affects vitamin B-12 metabolism. Am J Clin Nutr. 2005 Jun;81(6):1436-41. doi: 10.1093/ajcn/81.6.1436.

    PubMed 15941899
  • Bor MV, Nexo E, Hvas AM. Holo-transcobalamin concentration and transcobalamin saturation reflect recent vitamin B12 absorption better than does serum vitamin B12. Clin Chem. 2004 Jun;50(6):1043-9. doi: 10.1373/clinchem.2003.027458. Epub 2004 Mar 25.

    PubMed 15044317
  • Bor MV, Cetin M, Aytac S, Altay C, Nexo E. Nonradioactive vitamin B12 absorption test evaluated in controls and in patients with inherited malabsorption of vitamin B12. Clin Chem. 2005 Nov;51(11):2151-5. doi: 10.1373/clinchem.2005.055509. Epub 2005 Sep 15.

    PubMed 16166166

Questions about this trial

What is this clinical trial studying?

A study testing Vitamin B12 in people with Disorder of Vitamin B12, run by University of Florida at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 10 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 22 Dec 2011. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 14 Dec 2011). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Holo-transcobalamin (time frame: Holo-transcobalamin measured at 24 hours after baseline). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00235573, which also lists 3 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Dec 2011.

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