Fructose: Sugar's Dark Side?
Study: Fructose Increases Heart Risk Factors -- and Weight
WebMD News Archive
June 25, 2007 (Chicago) -- Cane sugar has a dark side, a provocative new
The sweetener we call sugar is actually a double sugar. Half is the sugar
called glucose, the body's most basic fuel. The other half is another sugar
called fructose. Researchers have suspected that fructose is a bad actor, but
the evidence so far has been circumstantial.
Can fructose really be worse for you than glucose? University of California,
Davis researchers Peter J. Havel, PhD, Kimber Stanhope, and colleagues designed
a clever study to find out.
First, they brought 23 overweight or obese adults, ranging in age from 43 to
70, into their clinical center. For two weeks, the volunteers' diets were
strictly controlled. They got a high-carb (55%), moderate-fat (30%) diet that
was balanced to give them no more energy than they spent in exercise.
After measuring their heart disease risk factors, such as blood fats,
cholesterol, and weight, the researchers set them free.
Then for eight weeks, the volunteers were allowed to eat whatever they
wanted except for one thing. Each person had to drink three sweetened beverages
every day -- which gave them 25% of their recommended daily energy intake.
Half the subjects drank beverages sweetened with pure glucose. The other
half got beverages sweetened with pure fructose. The researchers continued to
test them for heart risk factors.
After the eight weeks, the volunteers again were confined to the clinical
center, where they continued to drink their assigned beverages but had to
return to an energy-balanced diet.
Just two weeks after they started drinking the beverages, the dark side of
sugar became apparent. Those who drank fructose-sweetened beverages showed
signs of increasing risk of heart disease. Those who drank glucose-sweetened
beverages did not.
The fructose drinkers' LDL "bad" cholesterol, blood fats, and other
signs of worsening heart risk all increased. And alarmingly, their insulin
sensitivity decreased -- a sign that their diabetes risk was increasing,
Moreover, while both groups gained about 3 pounds, the fructose drinkers
gained the weight in deep abdominal fat This kind of fat increases a person’s
risk of diabetes and heart disease.
"Most people get the majority of the added sugars in their diet from
beverages," Havel tells WebMD. "We saw a lot of changes happen in just
two weeks of drinking these beverages -- and in real life, people don't do this
just for two or 10 weeks but as a lifelong habit. They are potentially exposing
themselves to cardiovascular risk."
The news may be worse. Stanhope says that preliminary data from new studies
show that regular sugar and high-fructose corn syrup each seem to have the same
effect as fructose alone -- even though both are only about half fructose and
half glucose (normal corn syrup is 100% glucose).