Background & aims: The inter-individual variations of the metabolic markers in response to dietary interventions may be mediated by genetic factors. We examined whether the type of dietary oils can modulate the effects of -75G/A polymorphism in APOA-1 gene on cardiometabolic markers.

Methods: This study was a randomized, triple-blind, cross-over clinical trial. Participants with and without type 2 diabetes were randomly assigned to replace their regular oil with sesame oil, canola oil and sesame-canola oil for 9 weeks. Genotyping was conducted using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results: Ninety-five diabetes patients and 73 healthy individuals completed the study protocol. In patients with type 2 diabetes, the A allele carriers experienced greater decrease in systolic blood pressure compared with GG homozygotes following sesame-canola oil intake. Serum levels of HDL-C and TG: HDL ratio was increased and decreased following canola oil intake in patients carrying the A allele rather than non-A allele carriers, respectively. More reductions for risk of cardiovascular diseases and mortality, except risk of stroke were found in the A allele carriers compared with GG homozygotes after intakes of canola and sesame-canola oils, but not sesame oil. There was also a significant genotype effect as well as genotype-dietary oil interactions on cardiovascular risk scores. In healthy individuals, a considerable decrease in visceral fat was accompanied by a significant increase in HDL-C levels in the A allele carriers compared with non-A allele carriers after sesame oil intake.

Conclusion: Patients with diabetes carrying the A allele might benefit from canola and sesame-canola oils intakes, and healthy A allele carriers from sesame and sesame-canola oils intakes as well. Future clinical trials are recommended to warrant current findings.

Keywords: Apolipoprotein A-I; Cardiovascular risk factors; Genetic polymorphism; Rapeseed oil; Sesame oil; Type 2 diabetes mellitus.