Impact of diets containing corn oil or olive/sunflower oil mixture on the human plasma and lipoprotein lipid metabolism.
Study Goal
The researchers aimed to compare the effects of a mixed oil diet (olive/sunflower oil) high in oleic acid with a PUFA-rich corn oil diet on human plasma and lipoprotein metabolism.
Results Summary
The PUFA-rich corn oil diet significantly reduced LDL cholesterol and showed trends in lowering total cholesterol and triglycerides, while the mixed oil diet had less influence on lipoprotein metabolism. Both diets left HDL cholesterol unchanged.
Population
28 healthy, non-smoking young men aged 19-31 years.
Effective Dosage
12 g sunflower oil/day (as part of a 68 g olive oil + 12 g sunflower oil mixture).
Duration
2 weeks per diet, with a crossover after 2 weeks.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
PUFA-rich corn oil diet | decrease | low density lipoprotein (LDL) cholesterol | 28 healthy, non-smoking young men aged between 19 and 31 years | significantly (p < 0.01) | was able to reduce | #1 |
PUFA-rich corn oil diet | decrease | total cholesterol | 28 healthy, non-smoking young men aged between 19 and 31 years | significantly lower | were significantly lower | #2 |
PUFA-rich corn oil diet | decrease | total triglycerides (TG) | 28 healthy, non-smoking young men aged between 19 and 31 years | significantly lower | were significantly lower | #3 |
PUFA-rich corn oil diet | decrease | very low density lipoprotein (VLDL)-TG | 28 healthy, non-smoking young men aged between 19 and 31 years | significantly lower | were significantly lower | #4 |
mixed oil diet (olive/sunflower oil mixture) | no change | total high density lipoproteins (HDL) | 28 healthy, non-smoking young men aged between 19 and 31 years | remained unchanged | remained unchanged | #5 |
mixed oil diet (olive/sunflower oil mixture) | no change | HDL cholesterol | 28 healthy, non-smoking young men aged between 19 and 31 years | remained unchanged | remained unchanged | #6 |
PUFA-rich corn oil diet | no change | total high density lipoproteins (HDL) | 28 healthy, non-smoking young men aged between 19 and 31 years | remained unchanged | remained unchanged | #7 |
PUFA-rich corn oil diet | no change | HDL cholesterol | 28 healthy, non-smoking young men aged between 19 and 31 years | remained unchanged | remained unchanged | #8 |
BACKGROUND: The effects of monounsaturated fatty acids (MUFA) rich diets compared to those that are rich in polyunsaturated fatty acids (PUFA) as well as the effects of an intake of single oils compared to oil mixtures are controversially discussed and results are contradictory. AIM OF THIS STUDY: To evaluate the effects of a plant oil-mixture (olive/sunflower oil; saturated/monounsaturated/polyunsaturated (S/M/P) = 14:69:17) high in oleic acid but also showing a moderate content of polyunsaturated fatty acids (PUFA) in comparison with a single, PUFA rich corn oil (S/M/P = 13:33:54) used in a normal, balanced diet on human plasma and lipoprotein metabolism. METHODS: The double-blind designed study comprised 28 healthy, non-smoking young men aged between 19 and 31 years. After two weeks of adjustment (mixed, balanced diet: 11.6 MJ average, average fat intake approximately 105 g/d), the design included a two week test period in which a diet with 80 g corn oil/d vs a mixture of 68 g olive- and 12 g sunflower oil/d (total 80 g) as the main fat source was given, followed by a crossover after two weeks. Compliance and ingestion of diets were monitored by assessing the fatty acid pattern in LDL and by determination of alpha- and gamma-tocopherol in plasma and LDL. Results Diets were well incorporated due to the significant changes in plasma- and LDL-tocopherol levels and the significant different average ratio of oleic acid to linoleic acid in LDL. The PUFA-rich corn oil diet was able to reduce low density lipoprotein (LDL) cholesterol from adjustment to T2 significantly (p < 0.01), which was also confirmed by a trend after cross over (p=0.15). Total cholesterol (only after cross over at T3), total triglycerides (TG) and very low density lipoprotein (VLDL)-TG were significantly lower at T2 after the corn oil diet than after the mixed oil diet. Total high density lipoproteins (HDL) and HDL cholesterol remained unchanged by both diets. CONCLUSIONS: The results show that during the intervention of two weeks for each diet and the following cross over the corn oil diet had more influence on lipoprotein metabolism than the MUFA-rich diet. The hypocholesteremic effect of the PUFA-rich diet must also be connected with the high amount of unsaponifiable substances, mainly phytosterols in the corn oil.