Authors
Ruiz-Gutierrez V. Muriana FJ. Guerrero A. Cert AM. Villar J.
Institution
Instituto de la Grasa, CSIC, Hospital Universitario Virgen del Rocio,
Sevilla, Spain.
Title
Plasma lipids, erythrocyte membrane lipids and blood
pressure of hypertensive women after ingestion of dietary
oleic acid from two different sources.
Source
Journal of Hypertension. 14(12):1483-90, 1996 Dec.
Abstract
OBJECTIVE: To study the effect of a diet rich in mono-unsaturated fatty acids
(MUFA), from high-oleic sunflower oil (HOSO) and olive oil,
on plasma lipids, erythrocyte membrane lipids (including fatty acid
composition) and blood pressure of
hypertensive (normocholesterolaemic or hypercholesterolaemic) women. METHODS:
There were 16 participants who were hypertensive women aged 56.2 +/- 5.4
years. The participants ate a diet enriched with HOSO or
olive oil for two 4-week periods with a 4-week washout
period before starting the second type of MUFA diet. At entry and during
study of each diet, plasma lipids and apolipoproteins were measured by
conventional enzymatic methods. Erythrocyte membrane lipid and fatty acid
compositions were analysed by means of the latroscan thin-layer
chromatography/flame ionization detection technique and by gas
chromatography, respectively. Blood
pressure was also measured. The statistical analysis was
conducted by using Student's two-tailed paired t-test. RESULTS: In both
groups of hypertensive patients, there was a significant increase in plasma
high-density lipoprotein (HDL) cholesterol concentration after the HOSO or
olive oil diets, with regard to baseline. Additionally, a
significant decrease in plasma HDL2 cholesterol concentration and an increase
in plasma HDL3 cholesterol concentration were evident. The membrane
free-cholesterol concentration increased significantly and the phospholipid
concentration decreased significantly in erythrocytes after the
olive oil diet, though both MUFA diets produced a
significant decrease in the concentration of membrane esterified cholesterol.
Therefore, the molar ratio of cholesterol to phospholipids was raised
significantly in the erythrocyte membrane of hypertensive women after the
dietary olive oil, but not after the HOSO diet. In the
hypertensive and normo-cholesterolaemic group the HOSO diet significantly
increased the content in the erythrocyte membrane of oleic, eicosenoic,
arachidonic and docosapentaenoic acids, whereas the olive
oil diet increased the content of palmitoleic acid and long-chain
polyunsaturated fatty acids of the n-3 family besides, compared with
baseline. A significant decrease in linoleic acid was also evident. In the
hypertensive and hypercholesterolaemic group, the HOSO diet resulted in
significant increases in palmitoleic, oleic, eicosenoic and behenic acids,
whereas the olive oil diet enhanced the content of
arachidonic, docosapentaenoic and docosahexaenoic acids besides, with respect
to baseline. In addition, there was a significant decrease in stearic acid,
but only after dietary olive oil was there a decrease in
linoleic acid. The most important differences between the two MUFA diets were
the increase in n-3 fatty acids and the decrease in the n-6; n-3 fatty acids
ratio after dietary olive oil in the erythrocyte membranes
of hypertensive patients. Interestingly, a significant reduction in systolic
and diastolic blood pressures was only
evident after the ingestion of olive oil. CONCLUSION: These
data suggest that the beneficial effects of dietary olive
oil on the plasma lipids and lipoprotein profile, lipid and fatty acid
composition of erythrocyte membrane, and blood
pressure in women with untreated essential hypertension are
not found equally for the HOSO-rich diet, despite both vegetable oils
providing a similar concentration of MUFA.