Mediterranean green diet cuts non-alcoholic fatty liver disease in half

A green Mediterranean diet (MED) reduces intrahepatic fat more than other healthy diets and cuts non-alcoholic fatty liver disease (NAFLD) in half, according to a long-term clinical trial conducted by researchers at Ben University -Gurion de Negev and a team of international colleagues.

The results were published in Intestine, an important international newspaper focusing on gastroenterology and hepatology.

“Our research team and other groups over the past 20 years have proven, through rigorous long-term randomized trials, that the Mediterranean diet is the healthiest,” said lead researcher Prof. Iris Shai, epidemiologist at the School of Public Health BGU who is also an adjunct professor at the Harvard School of Public Health TH Chan. “Now, we refine this diet and discover elements that can cause dramatic changes in liver fat and other important health factors.” Other Harvard researchers are Profs. Meir Stampfer and Frank Hu, head of the Chan School’s Nutrition Department.

NAFLD affects 25% to 30% of people in the United States and Europe. Although some fat is normal in the liver, excess fat (5% or more) leads to insulin resistance, type 2 diabetes, cardiovascular risk, as well as decreased diversity of the intestinal microbiome and microbial imbalance. Since no medication is available to treat fatty liver, the only intervention is weight loss and reduced alcohol consumption.

This nutritional magnetic resonance clinical trial (called Direct-Plus), conducted by an international research team led by Prof. Shai, is the first to develop and test a new green Mediterranean diet. This modified MED diet is rich in vegetables, includes the daily intake of nuts (28 grams) and less processed and red meat. It is enriched with green components, rich in polyphenols, including three to four cups of green tea / day and 100 grams (frozen cubes / day) of a green Mankai shake. Mankai, an aquatic green plant also known as duckweed, is rich in bioavailable proteins, iron, B12, vitamins, minerals and polyphenols.

“Addressing this common liver disease through lifestyle-oriented intervention can promote a more effective nutritional strategy,” said Dr. Anat Yaskolka-Meir, first author and member of the BGU School of Public Health. “This clinical trial demonstrates an effective nutritional tool for NAFLD in addition to weight loss.”

This 18-month DIRECT-PLUS trial began in 2017 at the Negev Nuclear Research Center in Dimona, Israel, when 294 workers in their fifties with abdominal obesity were randomly divided into three groups: healthy diet, Mediterranean diet and green Mediterranean diet. In addition to the diet, all participants received a physical exercise regime with free registration at the gym. Participants underwent MRI scans to quantify the exact proportion of excess intrahepatic fat before and after the trial.

The results showed that every diet leads to a reduction in liver fat. However, the green MED diet resulted in the greatest reduction in liver fat (-39%), compared to the traditional Mediterranean diet (-20%) and healthy dietary guidelines (-12%). The results were significant after adjusting for weight loss.

Overall, the green MED diet produced dramatic reductions in fatty liver. The prevalence of NAFLD fell from 62% at baseline to 31.5% in the green Mediterranean group, to 47.9% in the Mediterranean group and 54.8% in the healthy diet group.

Specifically, higher intake of mankai and nuts and lower intake of red / processed meat were significantly associated with the extent of IHF loss, after controlling for other variables. Both MED groups had significantly higher levels of total plasma polyphenol. More specific polyphenols, found in nuts and Mankai, were detected in the green MED group. The researchers hypothesize that the effect of polyphenols and the reduction of red meat play a role in reducing liver fat.