Folic Acid Does Not Improve Endothelial Function in Obese Children and Adolescents

  1. Alexia S. Peña, MD1,
  2. Esko Wiltshire, MD, FRACP2,
  3. Roger Gent, DMU3,
  4. Lino Piotto, DMU3,
  5. Craig Hirte, BSC4 and
  6. Jennifer Couper, MD, FRACP15
  1. 1Endocrinology and Diabetes Department, Women's and Children's Hospital, North Adelaide, Australia
  2. 2Department of Paediatrics and Child Health, Wellington School of Medicine and Health Sciences, University of Otago, Wellington South, New Zealand
  3. 3Medical Imaging, Women's and Children's Hospital, North Adelaide, Australia
  4. 4Public Health Research Unit, Women's and Children's Hospital, North Adelaide, Australia
  5. 5Discipline of Paediatrics, University of Adelaide, Australia
  1. Address correspondence and reprint requests to Alexia Peña, Endocrinology and Diabetes Department, Women's and Children's Hospital, 72 King William Rd., North Adelaide, SA 5006, Australia. E-mail: alexia.pena{at}adelaide.edu.au

Abstract

OBJECTIVE—Obese children have severe endothelial dysfunction as measured by flow-mediated dilation (FMD). We have shown that folic acid normalizes endothelial function in children with type 1 diabetes who have a similar degree of endothelial dysfunction but lower total plasma homocyst(e)ine (tHcy) and higher folate status. Our aim was to evaluate, for the first time, the effect of folate supplementation on endothelial dysfunction in obese children.

RESEARCH DESIGN AND METHODS—A total of 53 obese subjects (26 male, mean ± SD age 13.3 ± 2.2 years, and BMI Z score 2.29 ± 0.25) participated in a randomized, double-blind, placebo-controlled, parallel trial of oral folic acid (5 mg/day) or placebo for 8 weeks. Before and after the intervention, we assessed endothelial function (FMD), smooth muscle function (glyceryl trinitrate–induced dilatation [GTN]), high-sensitivity C-reactive protein (hsCRP), tHcy, serum folate, red cell folate (RCF), and lipids.

RESULTS—There were no group differences at baseline. FMD did not change with the intervention (folic acid group pre- and postintervention: 6.42 ± 5.03 and 6.56 ± 4.79%, respectively, vs. placebo group: 5.17 ± 3.54 and 5.79 ± 4.26%, respectively; P = 0.6). Folate supplementation increased serum folate and RCF by 18.4 nmol/l (P < 0.001) and 240.1 nmol/l (P < 0.001), respectively, and decreased tHcy by 0.95 μmol/l (P = 0.008). The intervention did not change GTN, hsCRP, or lipids.

CONCLUSIONS—Folic acid supplementation does not improve endothelial function in obese children without diabetes despite increasing folate status and reducing tHcy. This is in contrast to the response to folate in children with type 1 diabetes.

Footnotes

  • Published ahead of print at http://care.diabetesjournals.org on 22 May 2007. DOI: 10.2337/dc06-2505. Clinical trial reg. no. ACTRN012606000457549, clinicaltrials.gov.

    A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Accepted May 13, 2007.
    • Received December 12, 2006.
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