Diets varying in SFA and MUFA content can impact glycaemic control; however, whether underlying differences in genetic make-up can influence
blood glucose responses to these dietary
fatty acids is unknown. We examined the impact of
dietary oils varying in SFA/MUFA content on changes in
blood glucose levels (primary outcome) and whether these changes were modified by variants in the
stearoyl-CoA desaturase (SCD) gene (secondary outcome). Obese men and women participating in the randomised, crossover, isoenergetic, controlled-feeding
Canola Oil Multicenter Intervention Trial II consumed three
dietary oils for 6 weeks, with washout periods of ˜6 weeks between each treatment. Diets studied included a high SFA/low MUFA Control oil (36·6 % SFA/28·2 % MUFA), a conventional
canola oil (6·2 % SFA/63·1 % MUFA) and a high-
oleic acid canola oil (5·8 % SFA/74·7 % MUFA). No differences in fasting
blood glucose were observed following the consumption of the
dietary oils. However, when stratified by SCD genotypes, significant SNP-by-treatment interactions on
blood glucose response were found with additive models for rs1502593 (P = 0·01), rs3071 (P = 0·02) and rs522951 (P = 0·03). The interaction for rs3071 remained significant (P = 0·005) when analysed with a recessive model, where individuals carrying the CC genotype showed an increase (0·14 (sem 0·09) mmol/l) in
blood glucose levels with the Control oil diet, but reductions in
blood glucose with both MUFA oil diets. Individuals carrying the AA and AC genotypes experienced reductions in
blood glucose in response to all three
oils. These findings identify a potential new target for personalised nutrition approaches aimed at improving glycaemic control.