Table 1. Schematic illustration of the main diet-dependent epigenetic mechanisms reported in the text.

Epigenetic mechanism	Enzymes/processes involved	Effects on gene expression
DNA methylation The donation of a methyl group from a S-adenosyl-methionine (SAM) molecule to the position 5′ of the cytosine in CpG dinucleotide.	DNA methyl-transferases (DNMTs): DNMT1: maintenance of the methylation pattern after DNA replication. DNMT3a, DNMT3b: de novo methylation.	In the promoter of target genes: Hypermethylation: repression of gene expression. Hypomethylation: activation of gene expression.
Histone modifications The transfer of acetyl or methyl groups to lysine (Lys) and arginine (Arg) residues of histone proteins.	Histone acetyl-transferases (HATs): acetylation on Lys residues. Histone methyl-transferares (HMTs): methylation on Lys/Arg residues.	Histone acetylation: activation of gene expression. Histone methylation: activation/repression of gene expression.