Rapeseed oil fortified with micronutrients can reduce glucose intolerance during a high fat challenge in rats

Frederic Capel, Alain Geloen, Carole Vaysse, Gaelle Pineau, Luc Demaison, Jean-Michel Chardigny, Marie-Caroline Michalski, Corinne Malpuech-Brugère

Better choices of dietary lipid sources and substitution of refined by fortified oils could reduce the intake of saturated fatty acids (FA) and increase the intake of omega 3 FA concomitantly to healthy bioactive compounds. The development of obesity and metabolic disturbances was explored in rats fed during 11 weeks with a high fat diet (HFD) in which the amount of saturated and polyunsaturated FA was respectively reduced and increased, using rapeseed oil as lipid source. This oil was used in a refined form (R) or fortified (10 fold increase in concentration) with endogenous micronutrients (coenzyme Q10 + tocopherol only (RF) only and also with canolol (RFC)). The effect of substituting palm by rapeseed oil was analysed using a student t test, oil fortification was analysed using ANOVA statistical test. Despite a similar weight gain, diets R, RF and RFC improved glucose tolerance (+ 10%) of the rats compared to a standard HFD with palm and sunflower oils as lipid source. Plasma glucose was lowered in RF and RFC groups (- 15 and 23% respectively), although triacylglycerol level was only reduced in group RFC (- 33%) compared to R. The fortification with canolol promoted the activation of Akt and AMP-activated protein kinase (AMPK) in skeletal muscle and subcutaneous adipose tissue respectively. Canolol supplementation also led to reduce p38 MAPK activation in skeletal muscle. This study suggests that the presence of endogenous micronutrients in rapeseed oil promotes cellular adaptations to reverse glucose intolerance and improve the metabolism of insulin sensitive tissues.