Dietary polyunsaturated fatty acids may increase plasma LDL-cholesterol and plasma cholesterol concentrations in carriers of an ABCG1 gene single nucleotide polymorphism: Study in two Spanish populations

Background: ABCG1 mediates cellular cholesterol transport, but there is very little known about the influence of ABCG1 polymorphisms on human plasma lipoprotein cholesterol concentrations or on the interactions of these polymorphisms with diet. Objective: Our objective was to investigate whether interactions between PUFA intake and ABCG1 polymorphisms modulate associations with plasma total cholesterol (TC), LDL- and HDL-cholesterol in two Spanish populations. Methods: We grounded our investigation on two general population-based studies: the Hortega study (population A) and the Pizarra study (population B). Participants included 1178 individuals (50.0% women, age range 21-85 years) and 763 individuals (66% women, age range 23-73 years) from populations A and B, respectively, without lipid lowering drugs. Subjects were genotyped for ABCG1 variants. Biochemical measurements were taken by standard procedures. Dietary intakes were estimated with a validated questionnaire. Results: In population A, the A allele homozygotes of SNP rs4148102 had higher TC and LDLc concentrations in subjects on a high PUFA diet than did the carriers of the G allele (242.1 +/- 38.9 vs. 198.0 +/- 36.0 mg/dL, p = 0.003, and 149.8 +/- 37.9 vs. 111.4 +/- 32.1 mg/dL, p = 0.005, respectively), and significant gene-diet interactions were observed (p = 0.020 and p = 0.013, respectively). In population B, similar differences in TC and LDLc concentrations were also found in association with this SNP under a high PUFA diet (253.2 +/- 24.9 vs. 197.7 +/- 39.9 mg/dL, p = 0.009, and 171.8 +/- 20.5 vs. 120.4 +/- 34.2 mg/dL, p = 0.004, respectively), but the gene-diet interactions observed were not significant (p = 0.379 and p = 0.422, respectively). In the pooled populations, differences in the TC and LDLc concentrations increased (246.8 +/- 32.9 vs. 198.0 +/- 37.5, p = 6 x 10(-5), and 159.0 +/- 32.6 vs. 114.3 +/- 33.1, p = 3 x 10(-5), respectively), and significant gene-diet interactions were maintained (p = 0.006 and p = 0.003, respectively). Conclusion: In two Spanish populations, the ABCG1 polymorphism rs4148102 was associated with variations in plasma lipoprotein cholesterol concentrations in subjects with high PUFA intakes. Carriers of the AA genotype consuming high PUFA diet showed higher plasma LDLc concentrations. (C) 2011 Published by Elsevier Ireland Ltd.