Applied nutritional investigationEffects of extra virgin olive oil and fish oil on lipid profile and oxidative stress in patients with metabolic syndrome

- The Mediterranean diet is a rich source of olive oil and fish oil.
- Olive oil has shown beneficial results on lipid metabolism and oxidative stress.
- Fish oil has shown beneficial results on lipid metabolism and oxidative stress.
- Olive oil and fish oil have synergistic effects on lipid metabolism.
- Olive oil and fish oil have synergistic effects on oxidative stress.

ObjectiveThe aim of this study was to verify if extra virgin olive oil and fish oil have a synergistic effect on lipid and oxidative stress parameters in patients with metabolic syndrome (MetS).MethodsThis intervention study included 102 patients (81 women and 21 men) with MetS (mean age 51.45 ± 8.27 y) from the ambulatory center of the University Hospital of Londrina, Paraná, Brazil. Patients were randomly assigned to one of four groups: Patients in the control group (CG) were instructed to maintain their usual diet; the second group (fish oil group [FO]) received 3 g/d of fish oil ω-3 fatty acids (10 capsules); the third group (extra virgin olive oil group [OO]) received 10 mL/d of extra virgin olive oil at lunch and dinner; and the fourth group (fish oil and extra virgin olive oil group [FOO]) received 3 g/d of fish oil ω-3 fatty acids and 10 mL/d of extra virgin olive oil. MetS related markers and oxidative stress were measured at baseline and after 90 d.ResultsDifferences across treatment groups showed a statistically significant decrease (P < 0.05) in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) when FOO was compared with CG and OO, respectively. Hydroperoxides showed a significant decrease (P < 0.05) when FOO was compared with CG, whereas there was an increase in total peroxyl radical-trapping antioxidant potential/advanced oxidation protein products (TRAP/AOPP; P < 0.05) in FOO when compared with FO. In relation to baseline values, there was a significant decrease (P < 0.05) in LDL-C values, and TC/high-density lipoprotein cholesterol (HDL-C) and LDL-C/HDL-C indexes in FOO. There was also a decrease (P < 0.05) in hydroperoxides, in AOPP and in AOPP/TRAP index in FOO, and an increase (P < 0.05) in TRAP/AOPP index in FOO and in TRAP/uric acid ratio in OO.ConclusionThe present study provides evidence that increased dietary ω-3 polyunsaturated fatty acids and extra virgin olive oil have beneficial synergistic effects on lipid metabolism and oxidative stress in patients with MetS.