“Green” Mediterranean diet cuts liver disease by 50%, Israeli study flags
19 Jan 2021 --- A “green” Mediterranean diet that incorporates extra plant-based proteins and polyphenols can reduce the risk of non-alcoholic fatty liver disease (NAFLD) by half, according to a long-term clinical trial from Ben Gurion University of the Negev.
The findings, now published in Gut, show that the diet also cuts intrahepatic fat (IHF) by more than half compared to other nutritional strategies and diets.
“Our research team and other groups over the past 20 years have proven through rigorous randomized long-term trials that the Mediterranean diet is the healthiest,” says lead researcher Iris Shai.
“Now, we have refined that diet and discovered elements that can make dramatic changes to hepatic fat and other key health factors.”
The green Mediterranean diet follows the same principles as a traditional Mediterranean diet rich in vegetables, fish, nuts, olive oil, and restricted red meat and sugar.
However, it incorporates increased green plant-based proteins and polyphenols derived from ingredients such as green tea and duckweed (Wolffia globosa). This variant also more strictly restricts the use of red meats.
NAFLD affects 25 to 30 percent of people in the US and Europe. While some fat in the liver is healthy, excessive fat levels of 5 percent or higher can lead to insulin resistance, Type 2 diabetes, cardiovascular diseases, decreased gut microbiome diversity and microbial imbalance.
No drug is currently available to treat fatty liver, and the only intervention is weight loss and curtailing alcohol consumption.
“Addressing this common liver disease by targeted lifestyle intervention might promote a more effective nutritional strategy,” says study author Anat Yaskolka-Meir.
“This clinical trial demonstrates an effective nutritional tool for NAFLD beyond weight loss.”
“Dramatic” fat reductions
The 18-month trial, named Direct-Plus, began in 2017 at the Nuclear Research Center Negev in Dimona, Israel, with 294 workers in their 50s with abdominal obesity.
The participants were randomly assigned to follow one of three healthy dietary regimens.
The Mediterranean diet, the Green Mediterranean diet, or the Healthy Dietary Guidelines (HDG).
In the HDG, participants received standard nutritional counseling.
Those in the Green Mediterranean group consumed an additional three to four cups of green tea per day compared to the other groups. They also consumed 100 g of frozen duckweed per day in the form of Hinoman’s Mankai ingredient. This provided an additional 800 mg of polyphenols each day.
Along with each diet, all the participants were given a physical exercise regimen with a free gym membership. They also underwent MRI scans to quantify the exact proportion of excess intrahepatic fat before and after the trial.
The results showed that every diet led to liver fat reduction. However, the Green Mediterranean diet resulted in the greatest reduction of hepatic fat by 39 percent, in comparison with the traditional Mediterranean diet (20 percent) and the healthy dietary guidelines (12 percent).
The results remain significant after adjusting for weight loss.
In the Green Mediterranean group, NAFLD prevalence dropped from 62 percent at baseline to 32 percent.
This also fell to 48 percent in the Mediterranean group and 55 percent in the healthy dietary regimen group.
Polyphenol power
The researchers hypothesize that polyphenols and the reduction in red meat play a role in liver fat reduction.
Specifically, greater Mankai and walnut intake combined with lower red or processed meat consumption were significantly associated with IHF loss levels after controlling other variables.
Both Mediterranean diet groups had significantly higher total plasma polyphenol levels. More specific polyphenols, found in walnuts and Mankai, were also detected in the Green Mediterranean diet group.
Therefore, the researchers suggest more research and nutritional emphasis should be placed on the use of these ingredients for controlling liver fat levels and combating the prevalence of NAFLD.
Edited
By Louis Gore-Langton
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