August 6, 2009, Updated October 6, 2014

It may be a good idea to replace the juice in your kid’s lunch box with a bottle of water. A health conscious Israeli physician has bad news for the beverage industry. According to Dr. Nimer Assy, people who drink more than one liter (about four cups) of sweetened beverages a day have a five times greater risk of developing fatty liver.

“In the long term, this contributes to more diabetes and heart disease,” warns the doctor from the Ziv Medical Center in Haifa.

While known culprits like sweetened carbonated soda are on the list of “no-nos,” natural and freshly squeezed fruit juices appear there, too. His findings are reported in the Journal of Hepatology, where Assy, a specialist in internal medicine, liver disease and liver transplantation and director of the Liver Unit at Ziv, warns that the beverages cited can cause long-term damage.

In his study, Assy followed 90 healthy patients with no perceived risk for fatty liver. He discovered that about 80 percent of the people in the study who were diagnosed with fatty liver drank more than half a liter (about two cups) of sweetened soft drinks (carbonated beverages and sweetened juices) every day, whereas only 17% of those in the control group had the condition.

Don’t squeeze, chew!

The ingredient in the sodas and juices that causes the damage is a fruit sugar called fructose, which is highly absorbable in the liver. It does not affect insulin production and goes straight to the liver where it is converted to fat. Fructose ups the chances that you will suffer from a fatty liver, which can lead to cirrhosis of the liver and liver cancer, Assy tells ISRAEL21c.

The father of five, who lives in the Christian Arab village of Fassuta in the Galilee region of Israel, confesses that his own kids drink Coke. However, his advice to other parents is to limit their offsprings’ intake of soda or any sweetened beverage – natural or artificial – to not more than about one cup, juice box, or can, a day.

To reap optimal benefits from fruit and avoid the liver damage possibility, Assy suggests eating the fruit whole. “The natural orange has fibers and prevents fructose from being absorbed [in the liver],” he explains. If that’s not possible, he recommends drinking fruit juice that has extra pulp in it.

Assy’s study was spurred by what he saw at his in-patient clinic. “We have noticed recently that there are many patients coming to the clinic with fatty infiltration of the liver,” he tells ISRAEL21c. “Usually the risk factor is for people with obesity, diabetes and alcohol [abuse, but] we noticed some people without these pre-conditions could have fatty liver.”

Diet drinks are suspect as well

He started the study by asking his patients to take a questionnaire. As the group of 90 people (with a 50:50 ratio of women to men, ages 40 to 50) filled in the blanks, an explanation began to emerge. They were asked about their level of physical activity, caloric intake on a daily basis and the amount of soft drinks they consume.

“We found people who drink more than two cans of Coke a day have increased their chances for a fatty liver, and if left untreated their chances for heart disease and cirrhosis of the liver also increase,” Assy says.

When Assy refers to soft drinks, he’s including diet soft drinks in the mix. With inconclusive data on diet drinks, he believes that those containing artificial sweeteners may have a similar effect. While diet drinks do not contain fructose, they do have aspartame and caramel colorants: “Both these can increase insulin resistance and may induce fatty liver,” says the doctor.

Assy plans to conduct a more extensive study of the health effects of artificially sweetened drinks and he suspects that his findings may not be to the taste of the world’s beverage industry.

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