Efficacy of Weekly Versus Daily Folic Acid Supplementation

This study has been completed.
Centers for Disease Control and Prevention
Information provided by (Responsible Party):
Dr. Reynaldo Martorell, Emory University
ClinicalTrials.gov Identifier:
First received: October 31, 2006
Last updated: March 29, 2012
Last verified: March 2012
Investigate the efficacy of weekly versus daily of folic acid supplementation on improving folate, vitamin B12,

Condition Intervention
Neural Tube Defects
Drug: multivitamin

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double-Blind
Primary Purpose: Prevention

Resource links provided by NLM:

Further study details as provided by Emory University:

Primary Outcome Measures:
  • serum folate level
  • red blood cell folate

Secondary Outcome Measures:
  • homocysteine
  • ferritin
  • serum zinc
  • serum B12
  • blood pressure
  • depression

Estimated Enrollment: 460
Study Start Date: January 2006
Study Completion Date: July 2006
Primary Completion Date: June 2006 (Final data collection date for primary outcome measure)
Detailed Description:

460 women of a rural community in the western highlands of Guatemala were recruited for participation in the double-blinded study led by Emory University and the Institute of Nutrition of Central America and Panama (INCAP). The women were randomly assigned one of 4 vitamin treatments containing different levels of folic acid, Vitamin B12, iron and zinc. The treatments were as follows:

  1. weekly dose of folic acid at 5000ug, iron at 120 mg, zinc at 30mg, and B12 at 16.8 ug;
  2. weekly dose of folic acid at 2800ug, iron at 120mg, zinc at 0mg and B12 at 16.8ug;
  3. daily dose of folic acid at 400ug, iron at 60mg, zinc at 15mg, B12 at 2.4ug; and
  4. daily dose of folic acid at 200ug, iron at 50mg, zinc at 0mg, and B12 at 2.4ug.

The women, aged 15-49, received the vitamins daily for 3 months. Anthropometric data and blood samples were taken at baseline and post-supplementation. The participants also completed a series of dietary interviews at baseline and post-intervention. No pregnant or lactating mothers were admitted into the study, nor severely anemic females. Blood samples were sent to the National Laboratory in Cuernavaca, Mexico, for analysis of serum folate levels.


Ages Eligible for Study:   15 Years to 49 Years
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • female
  • aged 15-49

Exclusion Criteria:

  • pregnant
  • lactating less than 3 months
  • severely anemic
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00394862

Sponsors and Collaborators
Emory University
Centers for Disease Control and Prevention
Principal Investigator: Reynaldo Martorell, PHD, MPH Emory University
  More Information

Responsible Party: Dr. Reynaldo Martorell, Professor, Emory University
ClinicalTrials.gov Identifier: NCT00394862     History of Changes
Other Study ID Numbers: 205-2004 
Study First Received: October 31, 2006
Last Updated: March 29, 2012
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Neural Tube Defects
Spinal Dysraphism
Congenital Abnormalities
Nervous System Diseases
Nervous System Malformations

ClinicalTrials.gov processed this record on April 27, 2016