Comparison of the effects of consuming olive and sunflower oils on the fasting and postprandial blood glucose level and lipid profile in type 2 diabetic female patients

In type 2 diabetic patients, high fasting and postprandial triglyceride and decreased HDL-C levels are very common, increasing the risk of cardiovascular disease. This problem can be managed by dietary modifications, such as the reduction of saturated fatty acids (SFAs) intake and their substitution with monounsaturated fatty acids (MUFAs) or polyunsaturated fatty acids (PUFAs). This study was conducted to compare the effects of consuming olive and sunflower oils as a substitute for a portion of daily dietary fat on fasting and postprandial blood glucose level and lipid profile in type 2 diabetic female patients. This randomized crossover clinical trial was conducted on 15 postmenopausal women with type 2 diabetes (51.7  1.2 years old). Using a 3day 24-hour dietary recall questionnaire showed that their average daily intake of hydrogenated oil was 16.1±2.3g, 40% of total fat intake. The patients were randomly assigned to one of 2 groups, consuming either olive oil or sunflower oil (substituted for hydrogenated oil) for 3 weeks. After a washout period of 3 weeks, the subjects in each group switched to the other oil for the following 3 weeks. In all cases the subjects took their usual breakfast. Anthropometric measurements were made, physical activity was determined, and biochemical tests (fasting and postprandial blood sugar) were done at the beginning of the study and at the end of weeks 3, 6, and 9. Food intake was measured using the 24-h dietary recall technique and Nutritionist IV software at the same time points. As compared to sunflower oil, olive oil resulted in reductions in fasting blood glucose (p<0.01), triglycerides (p<0.01), postprandial blood triglyceride (p<0.05), and TG/HDL-C (p<0.05). There were no significant changes in anthropometric measurements, physical activity, or dietary intake of the patients during the study. As expected, substitution of hydrogenated fat with the 2 oils resulted in significant increases in the intakes of MUFA and PUFA and decreases in the intake of SFA (P<0.01). Considering the beneficial effects of olive oil on blood glucose and lipid profile, it can be concluded that partial substitution of dietary fat with olive oil, in preference to sunflower oil, can help reduce CVD risk factors in type 2 diabetic patients.