Fructose VS Glucose

By Margarita Nahapetyan

The scientists from University of California, Davis, came to the conclusion that in spite of the fact that different types of sugars such as glucose, fructose and sucrose all taste sweet, they have different effects on body. The study found that soft drinks and other beverages sweetened with fructose can have a negative effect on the body's sensitivity to insulin and its ability to handle fats, therefore increasing the risk of heart attack and stroke. And as to glucose-sweetened beverages, they do not have that kind of impact, the study found.

For the research, the experts involved 32 overweight and obese men and women with the average age of 50 years, who, for the period of ten weeks, were randomly assigned to two groups: 17 volunteers consumed beverages that contained fructose, and another 15 subjects were offered to drink glucose-sweetened beverages that supplied 25 per cent of their daily energy requirement. In order to exclude all intruding factors from the research, during the first and the last 2 weeks of the experiment, each volunteer was asked to undergo rigorous blood tests to determine levels of insulin and lipids, among other metabolic measures, at the University of California's Clinical and Translational Science Center.

After all blood tests of the participants have been analyzed, the experts found that volunteers in both groups had gained similar amount of pounds count by the end of week twelve. However, people who consumed fructose sweetened beverages with each meal, ended up with increased (1.5kg) belly fat, higher fatty triglycerides (which leads to heart disease) and 20 per cent higher insulin resistance (which leads to Type II Diabetes). These volunteers also gained more visceral fat. It is a dangerous kind of fat that embeds itself between organ tissues such as the heart, lungs, abdomen and liver and releases hormones and chemicals that have a severe impact on body's normal metabolism, which subsequently increases the risk of atherosclerosis and heart attack. None of this happened to the group on glucose.

The scientists said that average consumers drink beverages sweetened with either sucrose (50 per cent glucose, 50 per cent fructose) or high-fructose corn syrup (55 per cent glucose, 45 per cent fructose), rather than beverages that contain pure sugars. So, it may be that the adverse effects of these sweeteners are "diluted" by their lower fructose content relative to pure fructose, the researchers said. In addition, it is good to know that the average American consumes about 16 per cent of daily energy from added sugars, not the exaggerated 25 per sent that was offered to the participants of the study.

The findings could be important given that in 2005, the average American consumed 64 kilograms of added sugar, a significant amount of which came through consumption of soft drinks, said a lead author of the study, Dr. Peter Havel, M.D., of the University of California at Davis and his colleagues. Increased use of corn syrup (which is high in fructose) as a sweetener in soda drinks, in the last few decades has been proposed as one dietary change that has been contributing to obesity in developed countries, Matthias Tschöp and Susanna Hofmann of the University of Cincinnati-College of Medicine noted in their commentary.

According to food and drink manufacturers, the most common form of the syrup contains 5 per cent more fructose than glucose and is perceived as sweeter. The long-term effects of fructose still remain unknown, but it is clear that chronic over consumption of dietary sugars in general is bad for health, the experts noted. They also said that further studies and investigation are needed in order to determine what levels of dietary added sugars "are associated with adverse changes of lipids and decreased insulin sensitivity in different populations."

The study is published in the Journal of Clinical Investigation. The research was funded by grants from the National Institutes of Health, the National Center for Research Resources, the Roadmap for Medical Research, and the American Diabetes Association.