DNA methylation in PREDIMED-Navarra participants

Genome wide DNA methylation from peripheral white blood cells (PWBCs) from individuals enrolled in PREDIMED trial. The objective was to analyse whether an intervention with two Mediterranean diets, one rich in extra-virgin olive oil (MedDiet+EVOO) and the other one in nuts (MedDiet+nuts), was influencing the methylation status of PWBC genes. A group with a low-fat diet was considered as control. The Illumina Infinium 420k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in these samples. Samples included 12 MedDiet+EVOO, 12 MedDiet+nuts and 12 low-fat control group, at baseline (n=36) and after five years of intervention (n=36). Bisulphite converted DNA from the 72 samples (36 at baseline, 36 at 5 years after intervention, same individuals) were hybridised to the Illumina Infinium 450k Human Methylation Beadchip.