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A new study released in the online edition of Physiological Genomics finds
that individuals with a specific genetic variation consistently consume
more sugary foods. The study offers the first evidence of the role that
a variation in the GLUT2 gene - a gene that controls sugar entry into
the cells - has on sugar intake, and may help explain individual
preferences for foods high in sugar.
Study Summary
Food preferences are influenced by the environment as well as genetics.
Cravings for foods high in sugar vary from person to person, but the
reasons why are still unclear. To better understand the mechanism, the
research team examined the effect of a common variation in a gene that
controls the entry of sugar (glucose) into cells. The gene is called
glucose transporter type 2 or GLUT2.
The researchers tested the effects of the genetic variation in
two distinct populations. One population consisted of older adults who
were all either overweight or obese. The other population consisted of
generally healthy young adults who were mostly lean.
The diet of the participants in the first population was
assessed by recording all of the foods and beverages consumed over a
three day period, and repeating this 3-day food record two weeks later
to ensure that the effect was reproducible. All participants were
interviewed face-to-face during the two visits to the research centers.
For the second population, the study participants used a questionnaire
that asked about the foods and beverages typically consumed during a
one month period.
Blood was drawn from each participant, and their DNA
extracted. The researchers examined the genotype distribution and
compared the food intake data each participant provided between
individuals with the variation and those without the variation in
GLUT2. The DNA samples that carried the variation in GLUT2 were
associated with consuming more sugars in both populations studied.
Findings
The results of the study showed that a genetic variation of
GLUT2 is associated with differences in the habitual consumption of
sugars both within and between two distinct populations. Specifically:
- those individuals with the GLUT2 variation consistently
consumed more sugars (sucrose (table sugar)), fructose (simple sugar
such as corn syrup) and glucose (carbohydrates), regardless of age or
sex.
- the two sets of food records from the older group
showed that the older individuals with the variation consumed more
sugars than their non-variant older counterparts (112± 9 vs. 86±4 grams
of sugar per day and 111±8 vs. 82± 4 grams per day).
- the individuals in the younger population who
carried the variant were found to consume more sweetened beverages
(0.49±0.05 vs. 0.34±0.02 servings per day) and more sweets (1.45±0.10
vs. 1.08±0.05 servings per day) than their non-variant counterparts.
- there were no differences in the amount of protein,
fat, starch or alcohol that was consumed by those either with or
without the variant.
Conclusions
According to Dr. El-Sohemy, the study's senior researcher, "We
have found that a variation in the GLUT2 gene is associated with a
higher intake of sugars among different populations. These findings may
help explain some of the individual variations in people's preference
for sugary foods. It's especially important given the soaring rates of
obesity and diabetes throughout much of the world."
The study funded by the Advanced Food and Materials Network (AFMNet) and the Canadian Institutes of Health Research (CIHR).
was conducted by Ahmed El-Sohemy, Karen M. Eny,
Thomas M.S. Wolever and Benedicte Fontaine-Bisson, all of the
Department of Nutritional Sciences, University of Toronto, Toronto,
Canada. Their study, entitled Genetic Variant in the Glucose
Transporter Type 2 (GLUT 2) is Associated with Higher Intakes of Sugars
in Two Distinct Populations, appears in the May 2008 edition of Physiological Genomicshttp://physiolgenomics.physiology.org/).
Source: Donna Krupa
American Physiological Society (
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Nutrition 
