Diet, genetic and epigenetic signatures in women of childbearing age from a Mediterranean population: perspectives for public health

The aim of the study was to determine the association between Mediterranean diet (MD), folate intake and global DNA methylation in women of childbearing age. A total of 177 women were enrolled in a cross-sectional study. Folate intake and MD were assessed by a validated food frequency questionnaire. LINE-1 methylation level in leukocytes was measured by pyrosequencing. Women reported poor adherence to MD (mean value 4.1) and high prevalence of folate deficiency (83.1%). Mean level of LINE-1 methylation was 65.3%. A strong association between folate deficiency and global hypomethylation, was found: women with folate deficiency had a 4 fold increased risk to be hypometylated compared with women with no folate deficiency (OR = 4; 95% CI: 1.3 11.8). In multivariate analysis, the association decreased with a borderline confidence interval (p=0.053, OR = 3; 95% CI: 1 3.3). Poor adherence to MD was not directly associated with global methylation level, however, women whose consumption of fruit was below the median (201 gr/day) had a 2.8 fold increased risk to be hypometylated in comparison with those women whose consumption was above the median value (OR = 2.8; 95% CI: 1.3 5.8; p=0.019). In multivariate logistic regression analysis, results, adjusted for age, nutritional status, smoking habits and dietary caloric intake, showed a significant relationship between low fruits intake and low methylation level (p = 0.006; OR = 3.8; 95% CI: 1.5 9.7). The inverse association between high consumption of fruit, which represents a mainsource of folate, and DNA hypomethylation, suggests that dietary pattern characterized by a high intake of fruits and, in a broader view, great adherence to MD may protect against DNA hypomethylation.