DNA methylation changes in blood leukocytes following an omega-3 fatty acid supplementation

The objective is to investigate, using genome-wide DNA methylation analyses, methylation changes following an n-3 FA supplementation in overweight and obese subjects and to identify specific biological pathways potentially altered by the supplementation. A total of 36 non-smokers subjects, aged between 18 and 50 with a BMI between 25 and 40 kg/m2 were recruited. They received 3g of n-3 Fas (1.9-2.2g of EPA and 1.1g of DHA) per day for 6 weeks. Blood samples were taken before and after the supplementation period. Genomic DNA was extracted from blood leukocytes using GenElute Blood Genomic DNA kit (Sigma-Aldrich, USA) for the 72 samples: 36 sampels before and 36 samples after the supplementation. Three samples (one before and two after supplementation) were excluded from microarray analysis following quality control steps. Differences in methylation levels before and after the supplementation were tested using the Illumina Custom model in GenomeStudio software.