A polyphenol-rich green Mediterranean diet enhances epigenetic regulatory potential: the DIRECT PLUS randomized controlled trial

Anne Hoffmann, Anat Yaskolka Meir, Tobias Hagemann, Paul Czechowski, Luise Müller, Beatrice Engelmann, Sven Bastiaan Haange, Ulrike Rolle-Kampczyk, Gal Tsaban, Hila Zelicha, Ehud Rinott, Alon Kaplan, Ilan Shelef, Michael Stumvoll, Matthias Blüher, Liming Liang, Uta Ceglarek, Berend Isermann, Martin von Bergen, Peter KovacsMaria Keller, Iris Shai

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Background: The capacity of a polyphenol-enriched diet to modulate the epigenome in vivo is partly unknown. Given the beneficial metabolic effects of a Mediterranean (MED) diet enriched in polyphenols and reduced in red/processed meat (green-MED), as previously been proven by the 18-month DIRECT PLUS randomized controlled trial, we analyzed the effects of the green-MED diet on methylome and transcriptome levels to highlight molecular mechanisms underlying the observed metabolic improvements. Methods: Our study included 260 participants (baseline BMI = 31.2 kg/m2, age = 5 years) of the DIRECT PLUS trial, initially randomized to one of the intervention arms: A. healthy dietary guidelines (HDG), B. MED (440 mg polyphenols additionally provided by walnuts), C. green-MED (1240 mg polyphenols additionally provided by walnuts, green tea, and Mankai: green duckweed shake). Blood methylome and transcriptome of all study subjects were analyzed at baseline and after completing the 18-month intervention using Illumina EPIC and RNA sequencing technologies. Results: A total of 1573 differentially methylated regions (DMRs; false discovery rate (FDR) < 5 %) were found in the green-MED compared to the MED (177) and HDG (377) diet participants. This corresponded to 1753 differentially expressed genes (DEGs; FDR < 5 %) in the green-MED intervention compared to MED (7) and HDG (738). Consistently, the highest number (6 %) of epigenetic modulating genes was transcriptionally changed in subjects participating in the green-MED intervention. Weighted cluster network analysis relating transcriptional and phenotype changes among participants subjected to the green-MED intervention identified candidate genes associated with serum-folic acid change (all P < 1 × 10−3) and highlighted one module including the KIR3DS1 locus, being negatively associated with the polyphenol changes (e.g. P < 1 × 10−4), but positively associated with the MRI-assessed superficial subcutaneous adipose area-, weight- and waist circumference- 18-month change (all P < 0.05). Among others, this module included the DMR gene Cystathionine Beta-Synthase, playing a major role in homocysteine reduction. Conclusions: The green-MED high polyphenol diet, rich in green tea and Mankai, renders a high capacity to regulate an individual's epigenome. Our findings suggest epigenetic key drivers such as folate and green diet marker to mediate this capacity and indicate a direct effect of dietary polyphenols on the one‑carbon metabolism.

Original languageEnglish
Article number155594
JournalMetabolism: Clinical and Experimental
StatePublished - 1 Aug 2023


  • Cross-omics
  • DNA methylation
  • Folate
  • Lifestyle
  • mRNA expression
  • Obesity
  • Polyphenols
  • Randomized controlled trial (RCT)

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology


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