The findings, published in the journal Hepatology, could have implications for treating obesity and related diseases such as diabetes, insulin resistance and nonalcoholic fatty liver disease, said Dr. Jeffrey Browning, assistant professor in the UT Southwestern Advanced Imaging Research Center and of internal medicine at the medical center.
Glucose, a form of sugar, and fat are both sources of energy that are metabolized in the liver and used as energy in the body. Glucose can be formed from lactate, amino acids or glycerol.
In order to determine how diet affects glucose production and utilization in the liver, the researchers randomly assigned 14 obese or overweight adults to either a low-carbohydrate or low-calorie diet and monitored seven lean subjects on a regular diet.
After two weeks, researchers used advanced imaging techniques to analyze the different methods, or biochemical pathways, the subjects used to make glucose.
“We saw a dramatic change in where and how the liver was producing glucose, depending on diet,” said Dr. Browning.
Researchers found that participants on a low-carbohydrate diet produced more glucose from lactate or amino acids than those on a low-calorie diet.
“Understanding how the liver makes glucose under different dietary conditions may help us better regulate metabolic disorders with diet,” Dr. Browning said.
The different diets produced other differences in glucose metabolism. For example, people on a low-calorie diet got about 40 percent of their glucose from glycogen, which is comes from ingested carbohydrates and is stored in the liver until the body needs it.
The low-carbohydrate dieters, however, got only 20 percent of their glucose from glycogen. Instead of dipping into their reserve of glycogen, these subjects burned liver fat for energy.
The findings are significant because the accumulation of excess fat in the liver — primarily a form of fat called triglycerides — can result in nonalcoholic fatty liver disease, or NAFLD. The condition is the most common form of liver disease in Western countries, and its incidence is growing. Dr. Browning has previously shown that NAFLD may affect as many as one-third of U.S. adults. The disease is associated with metabolic disorders such as insulin resistance, diabetes and obesity, and it can lead to liver inflammation, cirrhosis and liver cancer.
“Energy production is expensive for the liver,” Dr. Browning said. “It appears that for the people on a low-carbohydrate diet, in order to meet that expense, their livers have to burn excess fat.”
Results indicate that patients on the low-carbohydrate diet increased fat burning throughout the entire body.
Dr. Browning and his colleagues will next study whether the changes that occur in liver metabolism as a result of carbohydrate restriction could help people with nonalcoholic fatty liver disease. Previous research has shown a correlation between carbohydrate intake and NAFLD.
Other researchers from the Advanced Imaging Research Center involved with the study were Dr. Matthew Merritt, assistant professor of radiology; Dr. Craig Malloy, professor of radiology and internal medicine; and Dr. Shawn Burgess, assistant professor of pharmacology. Other UT Southwestern researchers involved were Jeannie Davis, clinical research coordinator; and Santhosh Satapati, graduate student. A researcher from Texas Tech University Health Sciences Center also contributed.
The research was funded by the National Institutes of Health and the American Diabetes Association.
Visit http://www.utsouthwestern.org/digestive to learn more about UT Southwestern’s clinical services in digestive disorders, including liver diseases.
The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung
A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences