Telomeres are essential for the maintenance of genomic integrity. Telomere length declines with age and telomeredysfunction has been proposed as a biomarker for age-related diseases. Vitamin B12, B6 and folic acid are essential cofactorsfor numerous cellular processes including the synthesis of purines and nucleotides, DNA and protein methylation. B vitamindeficiencies and hyperhomocysteinemiaare risk factors for the development of age-related diseases. The aim of this study is toevaluate the effects of B vitamins on telomere biology.