A polymorphism exon 1 variant at the locus of the scavenger receptor class B type I (SCARB1) gene is associated with differences in insulin sensitivity in healthy people during the consumption of an olive oil-rich diet.
Scavenger receptor class B type I (SCARB1) was described as the first high-density lipoprotein receptor. Increasing evidence indicates that SCARB1 plays additional roles particularly in type 2 diabetes mellitus. Our aim was to determine whether the presence of an exon 1 (G-->A) polymorphism at the SCARB1 gene modifies the insulin sensitivity to dietary fat.


METHODS
We studied 59 healthy volunteers (30 men and 29 women, 42 G/G homozygous and 17 G/A heterozygous). Subjects consumed three diets for 4 wk each: a saturated fatty acid (SFA)-rich diet (38% fat, 20% SFA), followed by a carbohydrate (CHO)-rich diet (30% fat, 55% CHO) or a monounsaturated fatty acid (MUFA)-rich diet (38% fat, 22% MUFA) after a randomized crossover design. For each diet, we investigated peripheral insulin sensitivity with the insulin suppression test.


RESULTS
Steady-state plasma glucose after the MUFA diet was lower in G/A compared with G/G subjects (P = 0.030). This effect was not observed after CHO and SFA diets (P = 0.177 and 0.957, respectively). Plasma nonesterified free fatty acid values were lower in subjects carrying the A allele for all the diet periods.


CONCLUSIONS
Our findings show that carriers of the G/A genotype have significant increases in insulin sensitivity after a MUFA-rich diet compared with G/G individuals.
Pérez-Martínez
Pablo
P
Units of Lipids and Artherosclerosis, Hospital Universitario Reina Sofía, Avenida Menéndez Pidal, sin número 14004 Cordoba, Spain.
Pérez-Jiménez
Francisco
F
Bellido
Cecilia
C
Ordovás
José María
JM
Moreno
Juan Antonio
JA
Marín
Carmen
C
Gómez
Purificación
P
Delgado-Lista
Javier
J
Fuentes
Francisco
F
López-Miranda
José
J
D000328:Adult; D000483:Alleles; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D005091:Exons; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D000069463:Olive Oil; D010938:Plant Oils / Q000008:administration & dosage*; D011110:Polymorphism, Genetic; D011971:Receptors, Immunologic / Q000235:genetics* / Q000502:physiology; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B
D004040:Dietary Carbohydrates; D005230:Fatty Acids, Nonesterified; D000069463:Olive Oil; D010938:Plant Oils; D011971:Receptors, Immunologic; D051116:Receptors, Scavenger; C495124:SCARB1 protein, human; D051122:Scavenger Receptors, Class B