New insights into how a high protein diet protects from fatty liver

Reviewed by Emily Henderson, B.Sc.August 18, 2020

Non-alcoholic Fatty liver disease It is the most common chronic liver disease in the world and can have life-threatening consequences. A high-protein, low-calorie diet may dissolve harmful liver fats-more effective than a low-protein diet. New research by DIfE / DZD researchers published in the journal River International Demonstrate potentially involved molecular and physiological processes.

Causes and consequences of non-alcoholic fatty liver

Non-alcoholic fatty liver disease is characterized by the accumulation of fat in the liver and is often associated with obesity, type 2 diabetes, hypertension and lipid disorders. If left untreated, fatty liver can cause cirrhosis and can have life-threatening consequences. Causes of this disease range from an unhealthy lifestyle (that is, eating too much high-fat, high-sugar foods and lack of exercise) to a genetic component. Already in a previous study, a research team led by Dr Olga Ramich of PD and Professor Andreas Pfeiffer of the German Institute for Human Nutrition Potsdam Lebrücke (DIfE) observed a positive effect of a high protein diet on liver fat content. .. “The new results give us deeper insights into how a high protein diet works,” said Ramich, head of the Molecular Nutrition Medicine Research Group at DifE.

A high protein diet is more effective than a low protein diet

In the current study, a research team led by Ramich and Pfeiffer investigated how the protein content of foods affects hepatic fat mass in obese individuals with non-alcoholic fatty liver disease. For this reason, 19 participants followed either high or low protein diets for 3 weeks. Then, bariatric surgery (bariatric surgery) was performed, and a liver sample was collected.

In a sample analysis, a reduced-calorie, high-protein diet more effectively reduced liver fat than a reduced-calorie, lower-protein diet. Liver fat content in the high protein group was reduced by approximately 40%, while fat content in the low protein group liver samples was unchanged. Participants in both groups lost a total of approximately 5 kilograms.

If larger studies continue to confirm results, encouraging increased protein intake along with a healthy low-fat diet paves the way for medicine as part of effective fatty liver therapy There is a possibility. “

Andreas Pfeiffer, Head of the Clinical Nutrition/DZD Study Group at the Endocrinology Clinic at DifE and Charité-University of Berlin, Benjamin Franklin

Molecular fat absorption mechanism

Researchers attribute the positive effects of a high-protein diet primarily to the fact that fat intake, storage, and synthesis are suppressed. This is demonstrated by extensive genetic analysis of liver samples performed by Professor Stephan Herzig and his team of Helmholtz Zentrum München. These analyzes showed that many genes involved in fat absorption, storage, and synthesis in the liver were less active after high protein diet than after low protein diet.

Unexpected results

In addition, the Olga Ramich research group also investigated mitochondrial function along with the energy metabolism and physiology of DIfE. “Mitochondrial activity was very similar in both groups. It surprised us. We initially assumed that a high protein diet would increase mitochondrial activity, thereby contributing to liver fat breakdown. The researchers were also surprised that serum levels of fibroblast growth factor 21 (FGF21) were lower in the high protein diet after reducing liver fat than in the low protein diet. “FGF21 is known to have beneficial effects on metabolic regulation. Further research is needed to show why the factors are actually reduced in a high protein diet that is positively acting,” Ramich said. Stated. Moreover, autophagy activity was lower in liver tissue after a high protein diet compared to a low protein diet. “Therefore, lipolysis by the “fat diet” as a special form of autophagy does not appear to be involved in the breakdown of liver fat in a high protein diet. “

As a next step, Ramich and Pfeiffer will follow up on the findings of the mechanisms involved and gain new insights into the mechanisms of action of targeted dietary intervention strategies.