Effects of the mediterranean diet and virgin olive oil on the function of high-density lipoproteins and the atherogenicity of low-density lipoproteins in humans
- Autores: Álvaro Hernáez
- Directores de la Tesis: Montserrat Fitó Colomer (dir. tes.), María Isabel Covas Planells (dir. tes.), María Izquierdo Pulido (tut. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2016
- Idioma: español
- Tribunal Calificador de la Tesis: Jorge Ordóñez Llanos (presid.), Rosa María Lamuela Raventós (secret.), Jesús de la Osada García (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Cardiovascular diseases are the main cause of death worldwide and a relevant source of economic cost and physical disability. The Mediterranean Diet, associated with a high intake of virgin olive oil, has been shown to be protective against the development of cardiovascular diseases. Adherence to the Mediterranean Diet and the consumption of virgin olive oil induce this protection by improving several cardiovascular risk factors, such as the lipid profile. These two dietary interventions are known to increase cholesterol levels in high-density lipoproteins (HDLs) and decrease cholesterol concentrations in low-density lipoproteins (LDLs). However, it is becoming increasingly more accepted that the information provided by HDL and LDL cholesterol levels is quite limited. On the one hand, the biological functions of HDLs may reflect the anti-atherogenic role of the lipoprotein better than HDL cholesterol levels. On the other hand, several LDL characteristics beyond LDL cholesterol levels, such as the pro-atherogenic LDL traits (LDL size, oxidation, composition, etc.), may be more informative with respect to the unexplained cardiovascular risk of an individual. Nevertheless, despite their growing relevance, very few randomized controlled trials have examined the effects of healthy lifestyle modifications on these properties.
The aim of the present thesis project was to assess whether adherence to the Mediterranean Diet or the consumption of virgin olive oil was able to increase HDL functionality and decrease LDL pro-atherogenic traits in humans.
Samples in the present project were obtained from two randomized controlled trials: the EUROLIVE Study (Effects of Olive Oil Consumption on Oxidative Damage in European Populations) and the PREDIMED Study (Effects of Mediterranean Diet on the Primary Prevention of Cardiovascular Disease). In both cases, we isolated HDLs and LDLs in different sub-samples from volunteers in order to perform a complete battery of determinations related to HDL function and LDL atherogenicity.
The consumption of virgin olive oil increased the main HDL function: its cholesterol efflux capacity. An increase in the content of olive oil phenolic compounds in HDL, as well as the enhancement of HDL composition and size, may explain the functional improvement. Regarding the Mediterranean Diet, increasing adherence to this dietary pattern improves the four main HDL functions: cholesterol efflux capacity, HDL role in other steps of reverse cholesterol transport, HDL antioxidant activities, and HDL vasodilatory capacity. An improvement in HDL oxidation, size, and composition may also justify HDL enhanced function.
In addition, the consumption of virgin olive oil decreased LDL levels and LDL atherogenicity (increasing LDL size and resistance against oxidation). Adherence to the Mediterranean Diet also improved LDL pro-atherogenic traits, by increasing LDL size and resistance against oxidation, decreasing LDL oxidation in vivo, improving LDL composition, and decreasing LDL cytotoxicity in macrophages.
In conclusion, the present PhD thesis project shows that the consumption of virgin olive oil and adherence to the Mediterranean Diet improved HDL function and LDL pro-atherogenic traits in humans in two randomized controlled trials. Our findings provide two novel mechanisms to explain part of the benefits of these healthy diet interventions, and support previous evidence concerning the cardioprotective role of
