Green-Enriched Mediterranean Diet Can Double Intrahepatic Fat Loss, Curb NAFLD

Following a Mediterranean diet (MED) enriched with protein-rich Mankai duckweed, green tea and walnuts and restricted in red and processed meat (green-MED) could double intrahepatic fat loss and reduce non-alcoholic fatty liver disease (NAFLD), researchers say.

"Results from our previous DIRECT, CASCADE, and CENTRAL trials indicated that the Mediterranean diet is superior to other diets in terms of reducing cardiometabolic risk, for example, by achieving lower blood lipids levels," Dr. Anat Meir of Ben-Gurion University of the Negev in Beer-Sheva told Reuters Health by email.

"In the current trial, DIRECT PLUS," she said, "we enriched the Mediterranean diet with specific polyphenols such as Mankai, walnuts, and green tea and instructed participants to avoid red and processed meat to examine whether we can enhance the observed and known effect of the Mediterranean diet on cardiometabolic risk parameters."

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For the 18-month trial, published in Gut, Dr. Meir and colleagues randomly assigned 294 participants with abdominal obesity/dyslipidemia to one of three groups: one asked to follow healthy dietary guidelines (HDG), one following MED and one following the green-MED; all included physical activity.

Participants' mean age was 51, 88% were men, the mean BMI was 31.3, and the mean intrahepatic fat percentage (IHP%) was 10.2%. Sixty-two percent had NAFLD.

The daily diet for both MED groups included 28 g walnuts, which provided an additional 440 mg/day polyphenols. The green-MED group also consumed three to four cups of green tea and a green shake made from 100 g frozen cubes of Mankai, a Wolffia globosa aquatic plant strain, which provided 1,240 mg total polyphenols.

From an initial prevalence of 62%, NAFLD rates declined in all three groups, to: 54.8% (HDG), 47.9% (MED) and 31.5% (green-MED). Although both MED groups experienced moderate weight-loss, the green-MED group achieved almost double the IHF% loss (−38.9% proportionally), as compared with MED (−19.6% proportionally; weight loss adjusted) and HDG (−12.2% proportionally).

At 18 months, both MED groups had significantly higher total plasma polyphenol levels (0.47 mg/L for both) compared with the HDG group (0.35 mg/L), although green-MED had higher levels of Naringenin and 2-5-dihydroxybenzoic acid.

Greater IHF% loss was independently associated with increased Mankai and walnuts intake; decreased red/processed meat consumption; improved biomarkers of serum folate and adipokines/lipids; changes in microbiome composition, indicating beta-diversity; and specific bacteria, including Fournierella, Anaerosporobacter, and Lachnospiraceae_UCG-003.

Eight bacteria were also associated with the IHF 18-month change.

The study had a retention rate of 89.8%. Dr. Meir noted, "Participants easily adjusted to the green regimen, with no significant complaints regarding the taste."

"One limitation of our study is that we had a high proportion of male participants" recruited from the same workplace, she noted. "Regarding age, we observed a slightly higher reduction in liver fat among participants who were above age 50. No race/ethnic issues were examined."

Dr. Fatima Cody Stanford of the Massachusetts General Hospital Weight Center in Boston commented by email, "For persons who have a history of fatty liver disease or excess weight in their midsection, this diet would be one to consider to help reduce liver fat."

"While this diet may be slightly stricter than a Mediterranean, I think it would be feasible to follow it," she told Reuters Health. "However, you will need patients that are committed to the consistent green tea consumption and Mankai green shake."

"Personally, I find many green foods to be quite palatable," she noted. "However, a minority of patients might not. As such, this may be challenging for them to follow. The only issues that might arise are secondary to cultural differences in diet preference. These foods and beverages may be out of line with those in many cultures."

"The only foreseeable problem is the Mankai portion," she added. "It is not readily available in most parts of the world, and it is currently quite expensive. This will lend itself to issues with wide-scale application."

—Marilynn Larkin

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