The Ala54Thr polymorphism of the fatty acid-binding protein 2 gene is associated with a change in insulin sensitivity after a change in the type of dietary fat.
BACKGROUND
Insulin resistance, a condition associated with type 2 diabetes, results from the interaction of environmental and genetic factors.


OBJECTIVE
We examined the influence of the intestinal fatty acid-binding protein 2 (FABP2) Ala54Thr polymorphism on insulin sensitivity.


METHODS
Fifty-nine healthy young subjects (28 were Ala54/Ala54, 27 were Ala54/Thr54, and 4 were Thr54/Thr54) completed 3 diets, each of which lasted 4 wk. The first diet, which all subjects consumed, was a high-saturated fatty acid (SFA) diet (38% of energy as fat and 20% of energy as SFAs). The second and third diets were administered according to a randomized crossover design, and they consisted of a low-fat and high-carbohydrate diet (CHO diet; 28% of energy from fat and <10% of energy from SFAs) and a high-monounsaturated fatty acid (MUFA) diet (called the Mediterranean diet; 38% of energy from fat and 22% of energy from MUFAs). All food and drinks were prepared and provided in the research kitchen. We determined in vivo insulin resistance by using the insulin suppression test with somatostatin.


RESULTS
Steady state plasma glucose concentrations were significantly higher in Ala54Thr subjects after the SFA diet than after the CHO diet or the Mediterranean diet. The plasma free fatty acid concentrations in these subjects were significantly lower after the CHO and Mediterranean diets than after the SFA diet. However, no significant differences between the 3 diets were observed in the Ala54 allele homozygotes.


CONCLUSIONS
Insulin sensitivity decreased in subjects with the Thr54 allele of the FABP2 polymorphism when SFAs were replaced by MUFAs and carbohydrates.
Marín
Carmen
C
Lipids and Atherosclerosis Research Unit, Department of Medicine, Hospital Universitario Reina Sofía, School of Medicine, University of Cordoba, Córdoba, Spain.
Pérez-Jiménez
Francisco
F
Gómez
Purificación
P
Delgado
Javier
J
Paniagua
Juan Antonio
JA
Lozano
Aquiles
A
Cortés
Begoña
B
Jiménez-Gómez
Yolanda
Y
Gómez
María José
MJ
López-Miranda
José
J
D000328:Adult; D001786:Blood Glucose / Q000187:drug effects*; D002352:Carrier Proteins / Q000235:genetics*; D038441:Diet, Mediterranean; D004041:Dietary Fats / Q000494:pharmacology*; D050556:Fatty Acid-Binding Proteins; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005838:Genotype; D006801:Humans; D007333:Insulin Resistance / Q000235:genetics*; D011110:Polymorphism, Genetic
D001786:Blood Glucose; D002352:Carrier Proteins; D004041:Dietary Fats; C493404:FABP2 protein, human; D050556:Fatty Acid-Binding Proteins; D005230:Fatty Acids, Nonesterified