Harvard Health Letter

Rethinking fructose in your diet



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This naturally occurring sugar may not be as harmful as you've been hearing. Here's when you should avoid it.

Fructose is a common sugar found in fruits, vegetables, and honey. It's also a major ingredient in high-fructose corn syrup and table sugar. Recent studies have cast fructose as a bad guy, linking it to obesity, diabetes, and nonalcoholic fatty liver disease and inflammation, and leading to anti-fructose sentiment in the general media. But don't reject a food just because it contains fructose, says Dr. Bruce Bistrian, a professor at Harvard Medical School. "Fructose is naturally found in fruits. Fruits are not harmful and are even beneficial in almost any amount," he explains. Fruits contain lots of fiber. The fructose is bound to the fiber, which slows its absorption. Even more important, says Dr. Bistrian, "fruits and vegetables contain many other essential nutrients, such as flavonoids."

The nutritional problems of fructose—and of table sugar, which is another form of sugar called sucrose—come when they are added to foods, whether in the form of sucrose, high-fructose corn syrup, molasses, cane sugar, corn sweetener, raw sugar, syrup, honey, or fruit juice concentrates. "That should be limited," says Dr. Bistrian. "Those are empty calories in terms of not providing other nutrients." The higher intake of these forms of added sugar that is associated with an increased risk for obesity, type 2 diabetes, and cardiovascular disease.

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