Journal Name:
Proc. Natl. Acad. Sci. U. S. A.
Article Title:
Oleic acid content is responsible for the reduction in blood pressure induced by olive oil.
Date Written:
2008
Volume:
105
Number:
37
Page:
13811
Author(s):
Terés, S.; Barceló-Coblijn, G.; Benet, M.; Alvarez, R.; Bressani, R.; Halver, J.E.; Escribá, P.V.
Article:
Numerous studies have shown that high olive oil intake reduces blood pressure (BP). These positive effects of olive oil have frequently been ascribed to its minor components, such as alpha-tocopherol, polyphenols, and other phenolic compounds that are not present in other oils. Adrenergic receptors are key elements in the central and peripheral control of blood pressure (BP). Recent studies showed that the activity of the adrenoreceptor signaling pathway can be regulated by oleic acid (OA), specifically because of the effect of this fatty acid on the structure of cell membranes. A structural analogue of OA, 2-hydroxyoleic acid, can regulate membrane lipid structure and cell signaling in a similar manner as OA. Mediterranean areas have a significantly lower incidence of cardiovascular heart disease when compared with other European countries. This phenomenon has been associated with dietary habits, which improve parameters associated with major risk factors for cardiovascular disease, such as the lipoprotein profile, BP, endothelial function, and inflammation and oxidative stress.
The present study was designed to investigate the molecular basis of the hypotensive effect of olive oil by comparing the effects of olive oil, triolein (TO; the main constituent of olive oil, consisting of a TG with three OA moieties) and OA (the main fatty acid present in olive oil) on BP. In this study, the hypotensive effect of olive oil was found to be a result of its high oleic acid (OA) content. Olive oil intake increases OA levels in membranes, which regulates membrane lipid structure (H(II) phase propensity) in such a way as to control G protein-mediated signaling, causing a reduction in BP. This effect is in part caused by its regulatory action on G protein-associated cascades that regulate adenylyl cyclase and phospholipase C. In turn, the OA analogues, elaidic and stearic acids, had no hypotensive activity, indicating that the molecular mechanisms that link membrane lipid structure and BP regulation are very specific. Similarly, soybean oil (with low OA content) did not reduce BP. This study demonstrates that olive oil induces its hypotensive effects through the action of OA. Similar results could be expected with canola oil, due to its high levels of OA.
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