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Vitamin B6 Effects for Women Taking Birth Control Pills

This study is currently recruiting participants. (see Contacts and Locations)
Verified May 2014 by University of Florida
Sponsor:
Information provided by (Responsible Party):
University of Florida
ClinicalTrials.gov Identifier:
NCT01128244
First received: May 20, 2010
Last updated: May 19, 2014
Last verified: May 2014
  Purpose

Chronically inadequate B6 nutritional status is associated with aberrant one-carbon (1C) metabolism and health. Plasma PLP >30 nmol/L often has been considered to be the cutoff indicative of nutritional adequacy, with 20-30 nmol/L considered marginal deficiency; however, the current RDA value was based on a more conservative cutoff of 20 nmol/L plasma PLP. As shown by in the investigators preliminary data, biochemical perturbations occur when humans have marginal B6 deficiency consistent with plasma PLP of 20-30 nmol/L. A prospective study also showed that plasma PLP <23.3 nmol/L is associated with 1.8-times higher risk of recurrent venous thromboembolism than those with PLP >23.3 nmol/L. The mechanism by which low B6 intake is associated with risk of vascular disease is not known. Since B6-deficiency has little tendency to raise fasting plasma tHcy but yields an elevated tHcy response following a methionine load, low B6 nutriture may lead to repeated transient mild hyperhomocysteinemia following meal consumption. Several reports of associations between elevated plasma C-reactive protein (CRP) and low B6 status have raised the hypothesis that systemic inflammation is prone to occur during B6 deficiency or contributes to low B6 status. The investigators previously found that healthy humans in low B6 status caused by dietary restriction exhibited normal plasma CRP levels. The investigators also postulate that oxidative stress associated with low B6 status, coupled with impaired glutathione synthesis, contributes to such risk. These questions indicate the need for a more thorough understanding of the metabolic changes occurring in low B6 status from marginal B6 intake and from drug interactions such as in women using oral contraceptives.


Condition Intervention Phase
Vitamin B6 Deficiency
Dietary Supplement: Vitamin B6
Procedure: Infusion of amino acids, serine, and methionine
Phase 2
Phase 3

Study Type: Interventional
Study Design: Endpoint Classification: Pharmacokinetics Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Vitamin B6 Effects on One-Carbon Metabolism

Resource links provided by NLM:


Further study details as provided by University of Florida:

Primary Outcome Measures:
  • Change in flux of total remethylation of homocysteine [ Time Frame: Blood samples will be taken prior to infusion and at 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7.5, and 9h. Infusions will be conducted at baseline and after 28 days ] [ Designated as safety issue: No ]
    Outcome measurements include: (a) concentrations of metabolites associated with vitamin B6 metabolism and function, (b) the kinetics (rates) of metabolic reactions pertaining to one-carbon metabolism, and (c) the changes of the above variables following vitamin B6 supplementation.

  • Change in flux of homocysteine remethylation from serine-derived carbon [ Time Frame: Blood samples will be taken prior to infusion and at 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7.5, and 9h. Infusions will be conducted at baseline and after 28 days ] [ Designated as safety issue: No ]
    Outcome measurements include: (a) concentrations of metabolites associated with vitamin B6 metabolism and function, (b) the kinetics (rates) of metabolic reactions pertaining to one-carbon metabolism, and (c) the changes of the above variables following vitamin B6 supplementation.

  • Change in fasting plasma pyridoxal phosphate concentration [ Time Frame: Blood samples will be taken prior to infusion and at 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7.5, and 9h. Infusions will be conducted at baseline and after 28 days ] [ Designated as safety issue: No ]
    Outcome measurements include: (a) concentrations of metabolites associated with vitamin B6 metabolism and function, (b) the kinetics (rates) of metabolic reactions pertaining to one-carbon metabolism, and (c) the changes of the above variables following vitamin B6 supplementation.

  • Change in fasting cystathionine concentration [ Time Frame: Blood samples will be taken prior to infusion and at 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7.5, and 9h. Infusions will be conducted at baseline and after 28 days ] [ Designated as safety issue: No ]
    Outcome measurements include: (a) concentrations of metabolites associated with vitamin B6 metabolism and function, (b) the kinetics (rates) of metabolic reactions pertaining to one-carbon metabolism, and (c) the changes of the above variables following vitamin B6 supplementation.


Estimated Enrollment: 15
Study Start Date: April 2010
Estimated Study Completion Date: June 2015
Estimated Primary Completion Date: February 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Vitamin B6 Effects in OC Users
Subjects will be given an infusion of the amino acids serine and methionine prior to vitamin B6 supplementation and after 28 days of treatment. In addition, they will receive a special diet 2 days prior to the infusion and will have weekly weight, blood, and visits to the clinic.
Dietary Supplement: Vitamin B6
Subjects will receive vitamin B6 supplementation.
Other Names:
  • pyridoxine HCl supplement
  • USP pyridoxine HCL
Procedure: Infusion of amino acids, serine, and methionine
Subjects will be given an infusion of the amino acids, serine, and methionine prior to vitamin B6 supplementation and after 28 days of B6 treatment. In addition, they will receive a special diet 2 days prior to the infusion and will have weekly weight, blood, and visits to the clinic.

Detailed Description:

Potential subjects will undergo a prescreening visit to meet the inclusion criteria, have a history, physical exam and routine labs drawn. The labs will verify the nutritional eligibility of folate, vitamin B12 and vitamin B6. If the inclusion criteria is met then the following will take place.

The subjects will come to the CTSI Shands Clinical Research Unit (CRU) for a 9 hour infusion twice during the research study. Once at the start of the study and again at day 29. Blood samples will be taken for metabolite analysis. The infusion of nonradioactive, stable isotope labeled amino acids allows determination of the rate of metabolic reactions in one-carbon metabolism.

During the 2-days prior to the infusion a controlled diet will be required. The subjects will be fed at the CTSI Shands CRU. Dietary calculations and formulations will be conducted by using Minnesota Nutrition Data Systems software. Subjects will come to the CRU twice per day where they will meet with staff, consume morning and evening meals, and will be provided a sack lunch and snacks (including weekends). Protein intake will be kept constant.

After the first infusion, subjects will consume their self-selected usual diets for 28 days along with a commercial B6 supplement providing 10 mg/day. Weekly measurement of blood will be used to verify compliance. The subjects will then consume a 2-day controlled diet at the UF CRC to normalize protein intake, followed by an infusion procedure identical to the first.

During the 4-week supplementation period, subjects will come to the CRU weekly for weighing, blood samples, and consultation with staff. Careful screening, close monitoring and education of subjects, along with weekly monitoring of blood levels, all contribute to a high degree of compliance.

  Eligibility

Ages Eligible for Study:   20 Years to 40 Years
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • healthy female subjects
  • normal screening labs
  • normal body weight
  • nonpregnant
  • Plasma PLP<30nmol/L

Exclusion Criteria:

  • history of gastrointestinal surgery
  • chronic disease
  • vitamin supplementation
  • high protein diet
  • progesterone
  • no smoking
  • chronic drug use
  • alcoholism
  • no vitamin supplementation
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01128244

Contacts
Contact: Candy Caputo (352) 273-9023 Candace.caputo@medicine.ufl.edu
Contact: Luisa Rios-Avila, MS 352-392-1991 ext 266 lrios1@ufl.edu

Locations
United States, Florida
University of Florida Clinical Research Center Recruiting
Gainesville, Florida, United States, 32610
Sub-Investigator: Peter W. Stacpoole, MD, PhD         
Principal Investigator: Jesse Gregory, PhD         
Sponsors and Collaborators
University of Florida
Investigators
Principal Investigator: Jesse Gregory, PhD University of Florida
  More Information

No publications provided

Responsible Party: University of Florida
ClinicalTrials.gov Identifier: NCT01128244     History of Changes
Other Study ID Numbers: 2RO1DKO72398-05
Study First Received: May 20, 2010
Last Updated: May 19, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by University of Florida:
oral contraceptives
Vitamin B6
birth control pills
amino acids
Vitamin B6 deficiency
Vitamin B6 deficiency in women on oral contraceptives

Additional relevant MeSH terms:
Vitamin B 6 Deficiency
Avitaminosis
Deficiency Diseases
Malnutrition
Nutrition Disorders
Vitamin B Deficiency
Contraceptives, Oral
Contraceptives, Oral, Combined
Pyridoxal
Pyridoxine
Vitamin B 6
Vitamin B Complex
Vitamins
Contraceptive Agents
Contraceptive Agents, Female
Growth Substances
Micronutrients
Pharmacologic Actions
Physiological Effects of Drugs
Reproductive Control Agents
Therapeutic Uses

ClinicalTrials.gov processed this record on November 24, 2014