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Nutrition
Original research
Effect of green-Mediterranean diet on intrahepatic fat: the DIRECT PLUS randomised controlled trial
  1. Anat Yaskolka Meir1,
  2. Ehud Rinott1,
  3. Gal Tsaban1,2,
  4. Hila Zelicha1,
  5. Alon Kaplan1,
  6. Philip Rosen3,
  7. Ilan Shelef3,
  8. Ilan Youngster4,
  9. Aryeh Shalev2,
  10. Matthias Blüher5,
  11. Uta Ceglarek6,
  12. Michael Stumvoll5,
  13. Kieran Tuohy7,
  14. Camilla Diotallevi7,8,
  15. Urska Vrhovsek8,
  16. Frank Hu9,10,11,
  17. Meir Stampfer9,10,11,
  18. Iris Shai1,9
  1. 1 Department of Public Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
  2. 2 Division of Cardiology, Soroka Medical Center, Beer Sheva, Israel
  3. 3 Division of Diagnostic and Interventional Imaging, Soroka University Medical Center, Beer Sheva, Israel
  4. 4 Pediatric Division and Center for Microbiome Research, Shamir Medical Center, Be’er Ya’akov, Israel
  5. 5 Medical Department III – Endocrinology, Nephrology, Rheumatology, Leipzig University, Leipzig, Germany
  6. 6 Institute for Laboratory Medicine, Leipzig University, Leipzig, Germany
  7. 7 Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach, San Michelle All'Adige, Italy
  8. 8 Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy
  9. 9 Department of Nutrition, Harvard University T H Chan School of Public Health, Boston, Massachusetts, USA
  10. 10 Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
  11. 11 Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
  1. Correspondence to Dr Iris Shai, Department of Public Health, Ben-Gurion University of the Negev, Beer-Sheva 84105, Southern, Israel; irish{at}bgu.ac.il

Abstract

Objective To examine the effectiveness of green-Mediterranean (MED) diet, further restricted in red/processed meat, and enriched with green plants and polyphenols on non-alcoholic fatty liver disease (NAFLD), reflected by intrahepatic fat (IHF) loss.

Design For the DIRECT-PLUS 18-month randomized clinical trial, we assigned 294 participants with abdominal obesity/dyslipidaemia into healthy dietary guidelines (HDG), MED and green-MED weight-loss diet groups, all accompanied by physical activity. Both isocaloric MED groups consumed 28 g/day walnuts (+440 mg/day polyphenols provided). The green-MED group further consumed green tea (3–4 cups/day) and Mankai (a Wolffia globosa aquatic plant strain; 100 g/day frozen cubes) green shake (+1240 mg/day total polyphenols provided). IHF% 18-month changes were quantified continuously by proton magnetic resonance spectroscopy (MRS).

Results Participants (age=51 years; 88% men; body mass index=31.3 kg/m2; median IHF%=6.6%; mean=10.2%; 62% with NAFLD) had 89.8% 18-month retention-rate, and 78% had eligible follow-up MRS. Overall, NAFLD prevalence declined to: 54.8% (HDG), 47.9% (MED) and 31.5% (green-MED), p=0.012 between groups. Despite similar moderate weight-loss in both MED groups, green-MED group achieved almost double IHF% loss (−38.9% proportionally), as compared with MED (−19.6% proportionally; p=0.035 weight loss adjusted) and HDG (−12.2% proportionally; p<0.001). After 18 months, both MED groups had significantly higher total plasma polyphenol levels versus HDG, with higher detection of Naringenin and 2-5-dihydroxybenzoic-acid in green-MED. Greater IHF% loss was independently associated with increased Mankai and walnuts intake, decreased red/processed meat consumption, improved serum folate and adipokines/lipids biomarkers, changes in microbiome composition (beta-diversity) and specific bacteria (p<0.05 for all).

Conclusion The new suggested strategy of green-Mediterranean diet, amplified with green plant-based proteins/polyphenols as Mankai, green tea, and walnuts, and restricted in red/processed meat can double IHF loss than other healthy nutritional strategies and reduce NAFLD in half.

Trial registration number NCT03020186.

  • fatty liver
  • nutrition
  • magnetic resonance imaging
  • epidemiology

Data availability statement

The majority of results corresponding to the current study are included in the article or uploaded as supplementary material. No further data are avialable.

http://creativecommons.org/licenses/by-nc/4.0/

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

https://doi.org/10.1136/gutjnl-2020-323106

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    Data availability statement

    The majority of results corresponding to the current study are included in the article or uploaded as supplementary material. No further data are avialable.

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    Footnotes

    • AYM and ER contributed equally.

    • Contributors AYM, ER, GT, HZ, AK and IShai contributed to the data collection. AYM and ER made the statistical analysis, interpreted the data, reviewed the literature and drafted the manuscript. ER, GT, HZ, AK, PR, IShelef, IY, AS, MB, KT, CD, UV, UC, MStumvoll, FH, MStampfer and IShai contributed to the analysis and interpretation of data, and reviewed the language and intellectual content of this work. AYM and IShai revised the final draft of the study and approved the final version to be published.

    • Funding This work was funded by grants from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project number 209933838—Collaborative Research CenterCentre SFB1052 'Obesity Mechanisms', to I Shai (SFB-1052/B11); Israel Ministry of Health grant 87472511 (to I Shai); Israel Ministry of Science and Technology grant 3-13604 (to I Shai); California Walnuts Commission (to I Shai) and the Project 'Cabala_diet&health' (http://www.cabalaproject.eu/) which received funding from the European Union’s Horizon2020 research and innovation grant agreement No 696295—ERA-Net Cofund ERA-HDHL 'Biomarkers for Nutrition and Health implementing the JPI HDHL objectives' (https://www.healthydietforhealthylife.eu/) supported polyphenol analyses at FEM (to KT). AYM is a recipient of the Kreitman Doctoral Fellowship at Ben-Gurion University of the Negev. None of the funding providers were involved in any stage of the design, conduct or analysis of the study and they had no access to the study results before publication.

    • Competing interests IS advises to the Hinoman, Ltd. nutritional committee. Youngster is medical advisor for Mybiotix Ltd.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.