A Decreased Micronucleus Frequency in Human Lymphocytes after Folate and Vitamin B₁₂ Intervention: a Preliminary Study in a Yunnan Population

Background: Micronucleus (MN) is a validated biomarker for DNA damage in peripheral blood lymphocytes (PBL) and is a reflection of the changes of human nutritional status. Folate (FA) and vitamin B₁₂ are one-carbon metabolism-related micronutrients, which play important roles in maintaining genomic stability. Objective: To investigate the correcting effects of FA and B₁₂ intervention on DNA damage in PBL. Method: One hundred fifty-six volunteers without history of cancer were divided into 5 age groups (20 - 69 y, 47.4 % male) for establishing the baseline of chromosomal damage by means of cytokinesis-block micronucleus assay. Twelve individuals whose MN frequency was higher than the median value in each age group were selected for a four-month FA (200 - 400 μg/day)-B₁₂ (3.125 - 25 μg/day) intervention dosed as to age and MTHFR genotypes. Results: There were significantly positive correlations between age and MN frequency in all groups (p < 0.01). Among all age groups, the baseline MN frequencies were higher in females than that in males. The MN frequencies from 10 volunteers were reduced by 33.5 % after the intervention with the two micronutrients (p < 0.01), and two individuals did not show any changes. Conclusion: Dietary supplement intake of FA and B₁₂ based on MTHFR genotypes could protect the genome from damage and benefit genome health.