The
mitochondrial DNA (
mtDNA) 4977-bp deletion is a
biomarker of mitochondrial
genomic instability. It is frequently detected in a number of sporadic diseases, and it accumulates in many tissues during aging.
Folic acid plays an important role in the maintenance of
genomic stability in mammals. The aim of the present cross-sectional study was to characterise the levels of the
mtDNA deletion in the lymphocytes of healthy young women, taking into account
folate intake, red blood cell (RBC)
folate levels and the distribution of the
methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism.
Folate intake was estimated by a food frequency questionnaire. Determination of the MTHFR C677T polymorphism and of the
mtDNA deletion was performed by real-time polymerase chain reaction analysis. A total of 476 women were enrolled. Low levels of deletion were found (mean ΔCt = 1.24). After multivariate analysis, results did not show any significant relationship between age, smoking habits, pregnancy status, nutritional status, inadequate
folate intake,
folate deficiency, use of
folic acid supplements, MTHFR C677T polymorphism and
mtDNA 4977-bp deletions. The lack of association between inadequate
folate intake,
folate deficiency and mitochondrial
genomic instability was confirmed also considering reference values of
folate based on DNA damage prevention. Our results indicate that
mtDNA 4977-bp deletions are maintained at low levels in lymphocytes of young healthy women despite the wide range of variation of
folate intakes and
folate status. Future studies, carefully designed to address limits and methodological issues related to variation of this
biomarker as an effect of different dietary patterns and of
folate status, could provide further insight on the specific mechanisms that are acting in lymphocytes of healthy subjects under observed
folate intake.