Soft Drink Sweetener May Raise Obesity Risks
Fructose May Trigger Hormonal Response That Promotes Weight Gain
June 9, 2004 -- All sweeteners may not be created equal when it
comes to how they affect your weight.
New research suggests that fructose, a sweetener commonly used
in soft drinks and found naturally in fruit juice, may induce a hormonal
response in the body that promotes weight gain.
The study showed that drinking a fructose-sweetened beverage
caused levels of the hormones insulin and leptin to be lower than those found
after drinking a beverage sweetened with glucose, another natural
Insulin and leptin are hormones that send information to the
brain regarding the body's energy status and fat stores.
Researchers have previously linked low leptin levels to severe
obesity, possibly due to increased appetite. They have also shown that a
high-fat meal can lead to lower insulin and leptin levels.
Fructose also does not increase release of insulin and may lead to lower
leptin levels. Thus, the researchers wanted to see if a high-fructose diet
results in the same hormonal changes that result from a high-fat diet.
In addition, the study also showed that levels of another
hormone called ghrelin, which is thought to stimulate appetite and normally
declines after a meal, decreased less after drinking a fructose-sweetened
Fructose May Raise Obesity Risks
In the study, published in the Journal of Clinical
Endocrinology and Metabolism, researchers fed 12 normal-weight women
standardized meals containing the same number of calories and distribution of
total carbohydrate, fat, and protein on two days. On one day the meal included
a beverage containing fructose, and on the other day the same beverage was
sweetened with an equal amount of glucose.
Researchers collected blood samples from the women after each
meal and found several major differences in how the body responded to the two
Following meals containing the fructose-sweetened beverage
compared with the other:
- Leptin levels were lower (linked to increased appetite and weight gain) as
were insulin levels.
- Levels of the appetite-triggering hormone ghrelin decreased less.
- Fatty molecules in the blood called triglycerides experienced a prolonged
surge, which may raise the risk of heart disease.
Researchers say that taken together, the hormonal responses
after drinking beverages containing fructose suggest that diets high in
fructose may be one factor contributing to the current epidemic of obesity.
They estimate that fructose consumption has increased by
20%-30% over the last 30 years, a rate that is similar to the growth of obesity
rates during the same period.
Even though fructose is found naturally in fruit juice, these
findings would not likely apply to eating fruit. Other components of fruit,
such as the fiber, would affect how the body handles fructose.
Researchers say more studies are needed to look at the
long-term effects of fructose on appetite and energy.