Home  |  Top News  |  Most Popular  |  Video  |  Multimedia  |  News Feeds  |  Feedback
  Medicine  |  Nature & Earth  |  Biology  |  Technology & Engineering  |  Space & Planetary  |  Psychology  |  Physics & Chemistry  |  Economics  |  Archaeology
Top > Medicine, Health Care > Dietary Fructose Causes Liver Damage… >
Dietary Fructose Causes Liver Damage in Animal Model, Study Finds

Published: June 20, 2013.
By Wake Forest Baptist Medical Center
http://www.wfubmc.edu

WINSTON-SALEM, N.C. – June 19, 2013 – The role of dietary fructose in the development of obesity and fatty liver diseases remains controversial, with previous studies indicating that the problems resulted from fructose and a diet too high in calories.

However, a new study conducted in an animal model at Wake Forest Baptist Medical Center showed that fructose rapidly caused liver damage even without weight gain. The researchers found that over the six-week study period liver damage more than doubled in the animals fed a high-fructose diet as compared to those in the control group.

The study is published in the June 19 online edition of the American Journal of Clinical Nutrition.

"Is a calorie a calorie? Are they all created equal? Based on this study, we would say not," said Kylie Kavanagh, D.V.M., assistant professor of pathology-comparative medicine at Wake Forest Baptist and lead author of the study.

In a previous trial which is referenced in the current journal article, Kavanagh's team studied monkeys who were allowed to eat as much as they wanted of low-fat food with added fructose for seven years, as compared to a control group fed a low-fructose, low-fat diet for the same time period. Not surprisingly, the animals allowed to eat as much as they wanted of the high-fructose diet gained 50 percent more weight than the control group. They developed diabetes at three times the rate of the control group and also developed hepatic steatosis, or non-alcoholic fatty liver disease.

The big question for the researchers was what caused the liver damage. Was it because the animals got fat from eating too much, or was it something else?

To answer that question, this study was designed to prevent weight gain. Ten middle-aged, normal weight monkeys who had never eaten fructose were divided into two groups based on comparable body shapes and waist circumference. Over six weeks, one group was fed a calorie-controlled diet consisting of 24 percent fructose, while the control group was fed a calorie-controlled diet with only a negligible amount of fructose, approximately 0.5 percent.

Both diets had the same amount of fat, carbohydrate and protein, but the sources were different, Kavanagh said. The high-fructose group's diet was made from flour, butter, pork fat, eggs and fructose (the main ingredient in corn syrup), similar to what many people eat, while the control group's diet was made from healthy complex carbohydrates and soy protein.

Every week the research team weighed both groups and measured their waist circumference, then adjusted the amount of food provided to prevent weight gain. At the end of the study, the researchers measured biomarkers of liver damage through blood samples and examined what type of bacteria was in the intestine through fecal samples and intestinal biopsies.

"What surprised us the most was how quickly the liver was affected and how extensive the damage was, especially without weight gain as a factor," Kavanagh said. "Six weeks in monkeys is roughly equivalent to three months in humans."

In the high-fructose group, the researchers found that the type of intestinal bacteria hadn't changed, but that they were migrating to the liver more rapidly and causing damage there. It appears that something about the high fructose levels was causing the intestines to be less protective than normal, and consequently allowing the bacteria to leak out at a 30 percent higher rate, Kavanagh said.

One of the limitations of the study was that it only tested for fructose and not dextrose. Fructose and dextrose are simple sugars found naturally in plants.

"We studied fructose because it is the most commonly added sugar in the American diet, but based on our study findings, we can't say conclusively that fructose caused the liver damage," Kavanagh said. "What we can say is that high added sugars caused bacteria to exit the intestines, go into the blood stream and damage the liver.

"The liver damage began even in the absence of weight gain. This could have clinical implications because most doctors and scientists have thought that it was the fat in and around tissues in the body that caused the health problems."

The Wake Forest Baptist team plans to begin a new study using the same controls but testing for both fructose and dextrose over a longer time frame.


Show Reference »


Translate this page: Chinese French German Italian Japanese Korean Portuguese Russian Spanish


Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the ScienceNewsline.
Related »

People 
2/10/11 
Extensive Research Demonstrates Fructose Does Not Increase Food Intake Or Impact Weight
By Kellen Communications
A new comprehensive review, recently published in Critical Reviews in Food Science and Nutrition, concludes that fructose does not increase food intake or impact body weight or blood triglycerides …
Nicotine 
4/22/10 
Non-smokers Put on Less Weight
By FECYT - Spanish Foundation for Science and Technology
A new study links nicotine poisoning with weight gain, and concludes that active smokers, not only those who stop, put on more weight than non-smokers. After four years of …
Weight 
1/24/13 
Self-reported BMI Bias Estimates Increasing Due to Weight Bias, Not Weight Loss
By Public Library of Science
The gap between obesity levels measured by self-reported height and weight and obesity recorded by measured height and weight is increasing. This is due to an increasing bias in …
Mortality 
8/12/13 
Obesity And Mortality Association Differs Between Individuals with And Without Diabetes
By Springer
The relationship between body mass index (BMI) and mortality appears to be stronger in adults without diabetes than those with existing diabetes. These findings¹ are published in the Journal …
Genetics 
7/28/10 
Why Fad Diets Work Well for Some, but Not Others
By Genetics Society of America
Ever notice some people seem to eat anything they want and never gain a pound, while others seem to gain weight just by looking at fattening foods? You may …
Weight 
6/10/11 
★★★★ 
Discovery May Pave Way to Quitting Smoking Without Gaining Weight
By Yale University
Smokers tend to die young, but they tend to die thinner than non-smokers. A team of scientists led by Yale School of Medicine has discovered exactly how nicotine suppresses …
More » 

Most Popular - Medicine »
GENES »
Loss of Memory in Alzheimer's Mice Models Reversed Through Gene Therapy
MUTATIONS »
Applying Math to Biology: Software Identifies Disease-causing Mutations in Undiagnosed Illnesses
(SALT LAKE CITY)–A computational tool developed at the University of Utah (U of U) has successfully identified diseases with unknown gene mutations in three separate cases, U of U …
CHD »
Study: Iron Consumption Can Increase Risk for Heart Disease
TUMORS »
The Immune System's Redesigned Role in Fighting Cancerous Tumors
LOS ANGELES (March 11, 2014) – Researchers in the Cedars-Sinai Samuel Oschin Comprehensive Cancer Institute eradicated solid tumors in laboratory mice using a novel combination of two targeted agents. …
VACCINATION »
Impact of Whooping Cough Vaccination Revealed
The most comprehensive study to date of the family of bacteria that causes whooping cough points to more effective vaccine strategies and reveals surprising findings about the bacteria's origin …
ScienceNewsline  |  About  |  Privacy Policy  |  Feedback  |  Mobile  |  Japanese
The selection and placement of stories are determined automatically by a computer program. All contents are copyright of their owners except U.S. Government works. U.S. Government works are assumed to be in the public domain unless otherwise noted. Everything else copyright ScienceNewsline.