Eating
Disorders
Sweet Tooth
by Anne Petrov
 My favorite meal is dessert. You take the steak, leave me the Sara Lee!
But what is that makes some people salivate for the Porterhouse and others,
like me,
lust for the sweets?
The answer may be in the genes, according to a study published in the
American Journal of Clinical Nutrition.
"Although environmental, psychological and physiologic factors affect
appetite and nutrient intake, several studies suggest that
behaviors such as food and beverage preferences and nutrient intake are at
least partially genetically determined," reports Dr. Alan Shuldiner, of the
division of endocrinology, diabetes and nutrition at the University of Maryland
School of Medicine in Baltimore.
Shuldiner's team wanted to take a closer look at the genetics of obesity and
the eating behaviors that lead to it. To do this they studied the eating habits
and genetics of 624 adults from 28 Pennsylvania Amish families who participate
in the ongoing Amish Family Diabetes Study, which was started in 1995.
The Amish families "are wonderful for genetic studies," Shuldiner said in an
interview. "They are all descended from a homogenous founder population. They
all reside in a relatively localized area. And they keep extensive genealogic
records."
All study participants were asked to fill out an eating habits questionnaire
that included true or false queries, such as: "I do not eat some foods because
they make me fat"; "When I am with someone who overeats, I usually overeat too";
and "I get so hungry my stomach often feels like a bottomless pit."
The researchers were looking at three major eating behaviors. One is
restraint, a measure of whether a person can say no if he thinks another goody
might make him fat. Another is disinhibition, which is a measure of whether
people have a hard time saying no to a second helping of a favorite food. The
third is hunger.
Shuldiner and his colleagues also checked fasting blood sugar, cholesterol
and body mass index (BMI) for each study participant. BMI is a measurement of
weight in relation to height.
The researchers found that restraint, disinhibition and hunger scores
correlated with obesity and that high scores tended to run in certain families.
The investigators next decided to search the genome of the families with high
scores to see if they had bits of DNA in common. The researchers isolated
regions on certain chromosomes that seemed to be linked to restraint and
disinhibition.
While they haven't yet found the exact genes that are linked with each eating
behavior, there are candidates--found by other researchers--that reside on the
chromosomes of interest.
For example, Shuldiner's group found that a region of chromosome 3 appeared
to be linked to a person's ability to pass up second helpings of food. Located
in this section of the chromosome is a gene that encodes a receptor that is
found in large quantities in fatty tissue.
Shuldiner hopes that the genetic research will ultimately help scientists
find better treatments for obesity. "Insights gained by identifying genes that
influence eating behavior may provide new molecular targets for the early
detection of individuals susceptible to obesity, which may advance the
development of preventive interventions and provide new drug targets for the
treatment of obesity and related disorders," he and his colleagues write.
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