Foods high in fructose include anything with high fructose corn syrup, like sweetened drinks, candy and many processed foods, but this type of sugar also occurs naturally in fruits, fruit juices and honey.
"Cells don't use fructose for energy, so 100 percent of the fructose you eat is metabolized in your liver," said study co-author Dr. Valerio Nobili of Bambino Gesu Children's Hospital in Rome.
Instead, the body turns fructose into fatty acids, the "bad" kind of cholesterol and triglycerides, which are stored as body fat, Nobili said by email. "That's why excess fructose going into the liver is followed by the formation of fatty liver," Nobili added.
All of the study participants had at least some degree of nonalcoholic fatty liver disease, researchers report.
About 38 percent of them, or 102 participants, had more extensive liver damage known as nonalcoholic steatohepatitis (NASH) that happens when fat buildup leads to swelling in the liver and impairs liver function.
Roughly 47 patients with NASH had high uric acid, compared with 30 percent of participants without NASH, the study also found.
Overall, 53 percent of the children reported always skipping breakfast and another 26 percent said they had a morning meal infrequently.
However, 95 percent of the youth said they regularly had a morning snack and 89 percent routinely had an afternoon snack. Morning snacks most often included crackers, pizza and salty food, while afternoon snacks often consisted of biscuits or yogurt.
About 47 percent of the children ate cereal daily, while 43 percent had vegetables every day and 40 percent consumed fruit each day.
Roughly nine in 10 participants had soda at least once a week.
The youth with NASH had higher average consumption of fructose. Their median intake – meaning half of them consumed more – was about 70 grams of fructose daily. Median fructose consumption of children and teens without NASH was about 53 grams a day.
One limitation of the study is that it relied on children and teens to accurately recall and report what they ate, the authors note. The study also didn't examine whether there was a difference in liver outcomes based on how much fructose participants got from whole fruits, fruit juices or sodas.
"Our understanding of the role of fructose in fatty liver is still evolving," said Dr. Jeffrey Schwimmer, a researcher at the University of California, San Diego and director of the Fatty Liver Clinic at Rady Children's Hospital.
"We don't think that the impact of fructose from fruit is the same as fructose from drinks," Schwimmer, who wasn't involved in the study, said by email.
The difference in fructose consumption between youth with and without NASH in the study would be in one glass of sweetened tea or soda, but also the amount a child might get from pears or grapes, Schwimmer added.
His advice to parents: "Limit added sugars while further research is done to better understand" how fructose impacts the liver.
SOURCE: http://bit.ly/2lj2zPt Journal of Hepatology, online February 14, 2017.
© Reuters News 2017