Is Fructose Making People Fat?01/02/13
TUESDAY, Jan.1 (HealthDay News) -- New research suggests that
fructose, a simple sugar found naturally in fruit and added to many
other foods as part of high-fructose corn syrup, does not dampen
appetite and may cause people to eat more compared to another
simple sugar, glucose.
Glucose and fructose are both simple sugars that are included in
equal parts in table sugar. In the new study, brain scans suggest
that different things happen in your brain, depending on which
sugar you consume.
Yale University researchers looked for appetite-related changes
in blood flow in the hypothalamic region of the brains of 20
healthy adults after they ate either glucose or fructose. When
people consumed glucose, levels of hormones that play a role in
feeling full were high.
In contrast, when participants consumed a fructose beverage,
they showed smaller increases in hormones that are associated with
satiety (feeling full).
The findings are published in the Jan. 2 issue of the
Journal of the American Medical Association.
Dr. Jonathan Purnell, of Oregon Health & Science University
in Portland, co-authored an editorial that accompanied the new
study. He said that the findings replicate those found in prior
animal studies, but "this does not prove that fructose is the cause
of the obesity epidemic, only that it is a possible contributor
along with many other environmental and genetic factors."
That said, fructose has found its way into Americans' diets in
the form of sugars - typically in the form of high-fructose corn
syrup - that are added to beverages and processed foods. "This
increased intake of added sugar containing fructose over the past
several decades has coincided with the rise in obesity in the
population, and there is strong evidence from animal studies that
this increased intake of fructose is playing a role in this
phenomenon," said Purnell, who is associate professor in the
university's division of endocrinology, diabetes and clinical
But he stressed that nutritionists do not "recommend avoiding
natural sources of fructose, such as fruit, or the occasional use
of honey or syrup." And according to Purnell, "excess consumption
of processed sugar can be minimized by preparing meals at home
using whole foods and high-fiber grains."
Connie Diekman, director of university nutrition at Washington
University in St. Louis, agreed that more research is needed. "This
study provides an interesting look at how the brain reacts to
different chemicals found in foods, but how this might impact
obesity and the growing number of people who are obese cannot be
determined from this study alone," she said.
Dr. Scott Kahan, director of the National Center for Weight and
Wellness in Washington, D.C, added there is a lot that scientists
do not know about fructose and how it affects your body. "There are
certainly differences between sugar molecules, and these are still
being worked out scientifically," he said.
According to Kahan, high-fructose corn syrup, a ubiquitous
sweetener that manufacturers love because it is inexpensive,
super-sweet and helps extend shelf life, gets a bad rap about its
potential role in the obesity epidemic, but it has about the same
amount of fructose as table sugar (sucrose). "We don't entirely
know if there is some uniquely unhealthy aspect of high-fructose
corn syrup," he said.
One thing that is clear, Kahan said, is that "almost all of us
eat too much sugar, and if we can moderate that we will be
healthier on a number of levels."
Dr. Louis Aronne, founder and director of the Comprehensive
Weight Control Program at New York-Presbyterian Hospital/Weill
Cornell Medical Center in New York City, noted that most sweeteners
contain a mixture of glucose and fructose. For these reasons, "the
effect is not as dramatic as you might see in a trial like
Still, a growing body of evidence is pointing toward the
hypothalamic brain region as having a role in obesity. "Things as
subtle as a change in sweetener can have an impact on how full
somebody feels, and could lead to an increase in calorie intake and
an increasing pattern in obesity seen in this country," he
So what to do? As a nutritionist, Sharon Zarabi, of Lenox Hill
Hospital in New York City, tells her patients to read food labels.
"Avoid having fructose or glucose listed as one of as the first
three ingredients, and make sure that sugar is less than 10 grams
The American Heart Association has more about
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