Effect of green-Mediterranean diet on intrahepatic fat: the DIRECT PLUS randomised controlled trial - PubMed (original) (raw)

Randomized Controlled Trial

. 2021 Nov;70(11):2085-2095.

doi: 10.1136/gutjnl-2020-323106. Epub 2021 Jan 18.

Ehud Rinott # 1, Gal Tsaban 1 2, Hila Zelicha 1, Alon Kaplan 1, Philip Rosen 3, Ilan Shelef 3, Ilan Youngster 4, Aryeh Shalev 2, Matthias Blüher 5, Uta Ceglarek 6, Michael Stumvoll 5, Kieran Tuohy 7, Camilla Diotallevi 7 8, Urska Vrhovsek 8, Frank Hu 9 10 11, Meir Stampfer 9 10 11, Iris Shai 12 9

Affiliations

Randomized Controlled Trial

Effect of green-Mediterranean diet on intrahepatic fat: the DIRECT PLUS randomised controlled trial

Anat Yaskolka Meir et al. Gut. 2021 Nov.

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.

Keywords: epidemiology; fatty liver; magnetic resonance imaging; nutrition.

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

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Conflict of interest statement

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

Figures

Figure 1

Figure 1

Flow chart of the Dietary Intervention Randomized Controlled Trial Polyphenols Unprocessed study. HDG, healthy dietary guidelines; MED, Mediterranean.

Figure 2

Figure 2

(A–C)18-month changes in weight and intrahepatic fat. (A) 18-month absolute change in weight between intervention groups (ITT analysis, n=294). (B)18-month changes in IHF% between intervention groups (ITT analysis, adjusted p values for age, sex and baseline IHF%; n=269). (C) Illustrative MRI: a comparison of two male participants, similar age (46 years) and similar baseline WC (105 cm). Participant A was randomly assigned to the MED groups; participant B was assigned to the green-MED group. Both participants lost about 12% of their initial weight after 18 months and reported consuming at least 5–6 time/week walnuts (reported on 28 g/time). Total plasma polyphenol levels at the end of the intervention were higher in the green-MED participant versus MED participant (0.67 mg/L vs 0.24 mg/L). *Significant within-group change versus baseline at 0.05 level. Colour liver images were generated using pride software (by Philips). HDG, healthy dietary guidelines; IHF, intrahepatic fat; ITT, intention to treat; MED, Mediterranean; WC, waist circumference.

Figure 3

Figure 3

Changes in IHF across tertiles/categories of dietary components. Mankai shake and green tea tertiles are calculated from the weighted mean of consumption reported after 6 and 18 months of intervention. serum folate tertiles (of 18-month change in serum folate): T1≤−0.41; T2=−0.40 to 1.46; T3≥1.47; Mankai shake tertiles: T1≤1.67/week; T2=1.68 to 3.00/week; T3≥3.01/week; green tea tertiles: T1≤2/day; T2=2.01 to 3.67/day; T3≥3.68/day; walnut consumption categories: low: 0 to 1–3 times/month; medium: 1–2/week to 3–4/week; high: more than 5–6/week. Categories intervention group distribution for walnuts: low consumption: 60% MED, 40% green-MED; medium consumption: 45% MED, 55% green-MED; high consumption: 45% Med, 55% green-MED. Specific between tertiles/consumption group p values are corrected for multiple comparisons. # none of the participants reported on more processed meat. IHF, intrahepatic fat; MED, Mediterranean; T1, lowest tertile; T2, intermediate tertile; T3, highest tertile.

Figure 4

Figure 4

(A–D) Intrahepatic fat and the gut microbiome. (A) Gut microbiome composition (beta diversity) and IHF% at baseline. Gut microbiome composition and IHF, shown by principal coordinate analysis (PCoA) of UniFrac distances between all baseline samples. Colours denotes 1st (grey) 2nd (yellow) and 3rd (brown) IHF% tertiles. 95% SE ellipses are shown for each tertile. Boxplots on the right describe PCo1 score by IHF% tertile. (B) Gut microbiome composition change and IHF% change. Correlation between principal component 5 (PCo5), the principal coordinate most highly correlated with IHF change (Y axis), and 18-month change in intrahepatic fat. Colours denotes lifestyle intervention group allocation. Boxplots on the right describe PCo5 score by IHF% lifestyle intervention group. (C) Mediation analysis: assessing the proportional mediatory effect of microbiome composition change (measured as PCo5) in the association between lifestyle intervention and IHF% change. (D) Stepwise identification of genus level bacteria associated with: IHF% at baseline (top, two selected bacteria), IHF% 18-month change (middle, heatmap) and with lifestyle intervention (bottom, bar plot, selected bacteria). IHF, intrahepatic fat.

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