A high fructose diet harms the liver of laboratory animals, reports the American Journal of Clinical Nutrition.
Fructose, or fruit sugar, is found free in fruit, honey, flower nectar and mammalian semen (it is the “fuel” for sperm). Along with glucose, which makes it much sweeter, it is also part of sucrose, which is the ordinary sugar used to sweeten tea.
Fructose is absorbed by the body much more slowly than sucrose and glucose. It is sometimes used as a sugar substitute for diabetics. Significant amounts of fructose can cause diarrhea.
Controversy is the role of fructose in the development of obesity and fatty liver – previous studies have shown that the problems result from an overly caloric and fructose-rich diet and are associated with obesity.
However, new research conducted on an animal model by the team of Prof. Kylie Kavanagh of Wake Forest Baptist Medical Center has shown that fructose can damage the liver quickly – even without gaining weight. After six weeks, liver damage in monkeys on a high-fructose diet was twice as severe as in the control group.
To eliminate the effects of obesity, researchers selected 10 middle-aged, normal-weight monkeys that had never eaten fructose. They were divided into two groups. The first for six months got food containing 24 percent. fructose, the second – only 0,5 percent.
In both cases, the diet provided the same amount of fat, carbohydrate and protein, but their sources were different. The “fructose” group was fed flour, butter, lard, eggs, and fructose (mainly derived from corn syrup) – a diet that fit many people’s diets. The diet of the control group consisted of health-promoting complex polysaccharides and soy protein.
Scientists measured weight and waist circumference weekly to help prevent obesity in the monkeys by adjusting the diet. After the end of the experiment, they also tested the level of biomarkers in the blood indicating liver damage and what bacteria were present in the gut.
They found that despite the lack of obesity, a fructose-rich diet caused significant fatty liver after just six weeks. This corresponds to about three months on a human.
The fructose diet did not change the type of bacteria in the gut, but in unhealthy monkeys, the bacteria entered the bloodstream more quickly. (PAP)
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