February 28, 2012
Scientists Worldwide Join Forces To Show How Fructose Is Damaging Our Health
A group of scientists from across the world have come together in a just-published study that provides new insights into how fructose causes disease.
The intake of dietary fructose has increased significantly from 1970 to 2000. There has been a 25% increase in available "added sugars" during this period. The average person has a daily added sugar intake of 79 g (equivalent to 15% of energy intake), approximately half of which was fructose.
Foods high in fructose include such foods as processed vegetable condiments, ketchup, fruit juices, soda pop, and any food and drink sources with high fructose corn syrup.
The study found that fructose can be metabolized by an enzyme that exists in two forms. One form appears to be responsible for causing how fructose causes fatty liver, obesity, and insulin resistance. The other form may actually protect animals from developing these features in response to sugar.
These studies may provide important insights into the cause of the prediabetic condition known as "metabolic syndrome," which currently affects more than one-quarter of adults in the United States.
Previous studies have shown that eating too much fructose can induce leptin resistance, a condition that can easily lead to becoming overweight when combined with a high-fat, high-calorie diet.
According to a paper presented at the American Society of Nephrology's 42nd Annual Meeting and Scientific Exposition, cutting back on processed foods and beverages that contain high fructose sources may also may help prevent hypertension.
A segment of populations in most developed nations appear to be genetically predisposed to high blood insulin and triglyceride levels when consuming diets high in carbohydrate causing abnormal glucose tolerance. Reports indicate that maternal fructose intake may affect a child's endocrinology and glucose tolerance.
The study, "Opposing effects of fructokinase C and A isoforms on fructose-induced metabolic syndrome in mice" was just published in the journal Proceedings of the National Academy of Sciences. Richard Johnson, MD, the senior author of the study and Chief of the Division of Renal Diseases and Hypertension at the University of Colorado School of Medicine said the findings are significant because we now have a better understanding of how fructose causes obesity and other illnesses.
"Increased triglycerides after a meal are known predictors of cardiovascular disease," said Monell Member and Karen L. Teff, PhD, a metabolic physiologist. "Our findings show that fructose-sweetened beverages raise triglyceride levels in obese people, who already are at risk for metabolic disorders such as cardiovascular disease and diabetes."
"These studies provide new insights into how fructose may contribute to the development of obesity and diabetes. In particular, the identification of contrasting roles for two enzymes that are involved in fructose metabolism was surprising and could be important in understanding why some individuals may be more sensitive to the metabolic effects of fructose than others."
Previous research has shown that fructose intake in added sugars such as sucrose and high fructose corn syrup is strongly linked to the epidemic rise in obesity and nonalcoholic fatty liver disease. Fructose intake also causes features of metabolic syndrome in laboratory animals and humans. It is known to cause visceral (organ) fat accumulation and insulin resistance compared to starch based diets even when calories are kept even.
Faculty at the University of Colorado School of Medicine work to advance science and improve care. These faculty members include physicians, educators and scientists at University of Colorado Hospital, Children's Hospital Colorado, Denver Health, National Jewish Health, and the Denver Veterans Affairs Medical Center. Degrees offered by the CU Denver School of Medicine include doctor of medicine, doctor of physical therapy, and masters of physician assistant studies.