title: High plasma folate is negatively associated with leukocyte telomere length in Framingham Offspring cohort.
abstract: OBJECTIVE
  Shortening of telomeres, the protective structures at the ends of eukaryotic chromosomes, is associated with age-related pathologies. Telomere length is influenced by DNA integrity and DNA and histone methylation. Folate plays a role in providing precursors for nucleotides and methyl groups for methylation reactions and has the potential to influence telomere length.
  
  
  METHODS
  We determined the association between leukocyte telomere length and long-term plasma folate status (mean of 4 years) in Framingham Offspring Study (n = 1,044, females = 52.1 %, mean age 59 years) using data from samples collected before and after folic acid fortification. Leukocyte telomere length was determined by Southern analysis and fasting plasma folate concentration using microbiological assay.
  
  
  RESULTS
  There was no significant positive association between long-term plasma folate and leukocyte telomere length among the Framingham Offspring Study participants perhaps due to their adequate folate status. While the leukocyte telomere length in the second quintile of plasma folate was longer than that in the first quintile, the difference was not statistically significant. The leukocyte telomere length of the individuals in the fifth quintile of plasma folate was shorter than that of those in the second quintile by 180 bp (P < 0.01). There was a linear decrease in leukocyte telomere length with higher plasma folate concentrations in the upper four quintiles of plasma folate (P for trend = 0.001). Multivitamin use was associated with shorter telomeres in this cohort (P = 0.015).
  
  
  CONCLUSIONS
  High plasma folate status possibly resulting from high folic acid intake may interfere with the role of folate in maintaining telomere integrity.
authors.affiliation: JM USDA HNRC, Tufts University, 711 Washington St, Boston, MA, 02111, USA, Ligi.Paul_Pottenplackel@tufts.edu.
authors.forename: Ligi
authors.initials: L
authors.lastname: Paul
authors.forename: Paul F
authors.initials: PF
authors.lastname: Jacques
authors.forename: Abraham
authors.initials: A
authors.lastname: Aviv
authors.forename: Ramachandran S
authors.initials: RS
authors.lastname: Vasan
authors.forename: Ralph B
authors.initials: RB
authors.lastname: D'Agostino
authors.forename: Daniel
authors.initials: D
authors.lastname: Levy
authors.forename: Jacob
authors.initials: J
authors.lastname: Selhub
mesh_terms: D000368:Aged; D015331:Cohort Studies; D019587:Dietary Supplements / Q000009:adverse effects*; D005260:Female; D005492:Folic Acid / Q000009:adverse effects* / Q000097:blood; D005527:Food, Fortified / Q000009:adverse effects*; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007962:Leukocytes / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008404:Massachusetts; D008875:Middle Aged; D059506:Telomere Shortening; D015854:Up-Regulation
chemical_list: D006710:Homocysteine; D005492:Folic Acid