Improved insulin sensitivity and lower postprandial triglyceride concentrations after cold-pressed turnip rapeseed oil compared to cream in patients with metabolic syndrome.

Background: The aim of this study was to compare acute effects of turnip rapeseed oil rich with mono- and polyunsaturated fatty acids and cream on postprandial triglyceride levels and post-glucose load measures of insulin sensitivity in population of men with metabolic syndrome.

Methods: This open-label balanced crossover study included 37 men with metabolic syndrome. They underwent an oral glucose-fat tolerance test where they ingested 75 g of glucose with either 240 mL of cream or 84 mL of turnip rapeseed oil depending on the study arm. Hourly postprandial blood samples were drawn up to 5 h after this oral glucose-fat tolerance test to determine the changes in triglyceride concentrations and to measure insulin sensitivity. Changes in insulin sensitivity were calculated with different insulin sensitivity indices (OGIS, Stumvoll, Gutt and McAuley scores) derived from measured insulin and glucose concentrations. The oral glucose-fat tolerance test was preceded by a period during which the participants consumed a daily portion of either 35 mL of turnip rapeseed oil or 37.5 g of butter depending on the study arm in addition to their habitual diets. Both dietary periods lasted from 6 to 8 weeks. After an 8-week wash-out period the subjects crossed over to the other study arm and underwent the same process with the other fat adjunct.

Results: The area under the curve for hourly triglyceride concentrations was 16% smaller after turnip rapeseed oil than after cream (13.86 [interquartile range 8.54] vs. 16.41 [9.09] mmol/l, p < 0.001). The insulin sensitivity markers of OGIS (324 [38.97] vs. 377 [68.38] p < 0.001), Stumvoll score (0.079 [0.029] vs. 0.085 [0.029], p = 0.038) and Gutt score (67.0 ± 2.78 vs. 78.8 ± 4.97 p = 0.001) were higher after turnip rapeseed oil period than after butter period. There was a non-significant change in the McAuley score.

Conclusion: Dietary turnip rapeseed oil improved postprandially measured insulin sensitivity and triglyceride concentrations compared to cream and butter. This provides a possible efficient dietary mean to treat cardiovascular risk factors. ClinicalTrials.gov NCT01119690 (05-06-2010).