X-Message-Number: 12177
Date: Fri, 23 Jul 1999 09:26:36 -0700 (PDT)
From: Doug Skrecky <>
Subject: virgin olive oil may lower blood pressure

  Ruiz-Gutierrez V.  Muriana FJ.  Guerrero A.  Cert AM.  Villar J.
  Instituto de la Grasa, CSIC, Hospital Universitario Virgen del Rocio,
  Sevilla, Spain.
  Plasma lipids, erythrocyte membrane lipids and blood
  pressure of hypertensive women after ingestion of dietary
  oleic acid from two different sources.
  Journal of Hypertension.  14(12):1483-90, 1996 Dec.
  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.

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