Rats that eat high levels of a natural sugar known as fructose seem to age faster than other rats--and the same could be true for people who eat too much sweet junk food, Israeli researchers said Monday.
Fructose, found naturally in honey and fruit, is used widely in foods ranging from soft drinks to yogurt. But while its sweet taste is popular, the sugar could cause wrinkles and heal the problems, the researchers said. Dr. Moshe Werman and Boaz Levi of the Technion-Israel Institute of Technology fed large amounts of fructose to laboratory rats. Writing in the Journal of Nutrition, they said the fructose-fed rats showed changes n the collagen of their skin and bones.
Collagen, a fibrous protein found in connective tissue, bone and cartilage, basically holds the body together. The loss of collagen is what causes sagging and deep wrinkles in older people.
The process affected, Werman's team said, is known as "cross linking". "Too much cross-linking reduces elasticity and makes the skin stiff and rigid, and these are the conditions that encourage wrinkled skin," Werman said in a statement. He said the same could be true of people, although this has not been shown. "Americans are eating more and more processed foods such as carbonated drinks, baked goods, canned fruits, jams and dairy products that contain fructose," Werman said. Other studies have shown that high fructose intake can affect how the body handles glucose and increases insulin resistance---- which can both be important measures of the tendency toward diabetes.
The rats Werman worked with were fed much more than the average adult person might eat in a day, which is standard in such experiments. The rats were fed 12.5 grams of fructose per kg (2.2 pounds) of weight every day for a year. To compare, a person weighing 154 pounds (70kg) who drinks a quart (liter) of cola consumes about 60 grams of fructose, or 0.8 grams per kg of body weight.