title: Increased telomerase activity and vitamin D supplementation in overweight African Americans.
abstract: OBJECTIVE
  We aimed to investigate whether vitamin D supplementation modulates peripheral blood mononuclear cell (PBMC) telomerase activity in overweight African Americans.
  
  
  METHODS
  A double blind, randomized and placebo-controlled clinical trial (#NCT01141192) was recently conducted.
  
  
  METHODS
  African-American adults were randomly assigned to either the placebo, or the vitamin D group (60,000 IU per month (equivalent to ~2000 IU per day) oral vitamin D3 supplementation). Fresh PBMCs were collected from 37 subjects (18 in the placebo group and 19 in the vitamin D group), both at baseline and 16 weeks. PBMC telomerase activity was measured by the telomeric repeat amplification protocol.
  
  
  RESULTS
  Serum 25 hydroxyvitamin D levels increased from 40.7±15.7 at baseline to 48.1±17.5 nmol l(-1) at posttest (P=0.004) in the placebo group, and from 35.4±11.3 at baseline to 103.7±31.5 nmol l(-1) at posttests (P<0.0001) in the vitamin D group. In the vitamin D group, PBMC telomerase activity increased by 19.2% from baseline (1.56±0.29 absorbance reading unit (AU)) to posttest (1.86±0.42 AU, P<0.0001). The significance persisted after controlling for age, sex and body mass index (P=0.039). PBMC telomerase activity in the placebo group did not change from baseline (1.43±0.26 AU) to posttest (1.46±0.27 AU, P=0.157).
  
  
  CONCLUSIONS
  Vitamin D supplementation significantly increased PBMC telomerase activity in overweight African Americans. Our data suggest that vitamin D may improve telomere maintenance and prevent cell senescence and counteract obesity-induced acceleration of cellular aging.
authors: Georgia Prevention Institute, Department of Pediatrics, Georgia Health Sciences University, Augusta, GA 30912, USA. hzhu@georgiahealth.edu
authors: H
authors: H
authors: Zhu
authors: D
authors: D
authors: Guo
authors: K
authors: K
authors: Li
authors: J
authors: J
authors: Pedersen-White
authors: I S
authors: IS
authors: Stallmann-Jorgensen
authors: Y
authors: Y
authors: Huang
authors: S
authors: S
authors: Parikh
authors: K
authors: K
authors: Liu
authors: Y
authors: Y
authors: Dong
mesh_terms: D000328:Adult; D001741:Black or African American; D000704:Analysis of Variance; D002762:Cholecalciferol / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000178:diet therapy / Q000201:enzymology; D019098:Telomerase / Q000378:metabolism*; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D002762:Cholecalciferol; D006442:Glycated Hemoglobin; D019098:Telomerase; D014807:Vitamin D; C517652:hemoglobin A1c protein, human; C104450:25-hydroxyvitamin D