Re: Virgin olive oil reduces oxidative stress



On Tue, 26 Sep 2006 19:50:54 +0300, Juhana Harju wrote in
<news:4nt435Fc0lfjU1@xxxxxxxxxxxxxx> :


Extra virgin olive oils, high in phenolic compounds, reduce oxidative stress
markers according to a new randomized trial.

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Ann Intern Med. 2006 Sep 5;145(5):333-41.
The effect of polyphenols in olive oil on heart disease risk factors: a
randomized trial.
Covas MI, Nyyssonen K, Poulsen HE, Kaikkonen J, Zunft HJ, Kiesewetter H,
Gaddi A, de la Torre R, Mursu J, Baumler H, Nascetti S, Salonen JT, Fito M,
Virtanen J, Marrugat J, EUROLIVE Study Group.
Municipal Institute for Medical Research, Barcelona, Spain.

BACKGROUND: Virgin olive oils are richer in phenolic content than refined
olive oil. Small, randomized, crossover, controlled trials on the
antioxidant effect of phenolic compounds from real-life daily doses of olive
oil in humans have yielded conflicting results. Little information is
available on the effect of the phenolic compounds of olive oil on plasma
lipid levels. No international study with a large sample size has been done.
OBJECTIVE: To evaluate whether the phenolic content of olive oil further
benefits plasma lipid levels and lipid oxidative damage compared with
monounsaturated acid content. DESIGN: Randomized, crossover, controlled
trial. SETTING: 6 research centers from 5 European countries. PARTICIPANTS:
200 healthy male volunteers. MEASUREMENTS: Glucose levels, plasma lipid
levels, oxidative damage to lipid levels, and endogenous and exogenous
antioxidants at baseline and before and after each intervention.
INTERVENTION: In a crossover study, participants were randomly assigned to 3
sequences of daily administration of 25 mL of 3 olive oils. Olive oils had
low (2.7 mg/kg of olive oil), medium (164 mg/kg), or high (366 mg/kg)
phenolic content but were otherwise similar. Intervention periods were 3
weeks preceded by 2-week washout periods. RESULTS: A linear increase in
high-density lipoprotein (HDL) cholesterol levels was observed for low-,
medium-, and high-polyphenol olive oil: mean change, 0.025 mmol/L (95% CI,
0.003 to 0.05 mmol/L), 0.032 mmol/L (CI, 0.005 to 0.05 mmol/L), and 0.045
mmol/L (CI, 0.02 to 0.06 mmol/L), respectively. Total cholesterol-HDL
cholesterol ratio decreased linearly with the phenolic content of the olive
oil.

To keep the phenolic content high, let's use *extra virgin*, *well stored*,
*raw* olive oil. :)


Triglyceride levels decreased by an average of 0.05 mmol/L for all
olive oils. Oxidative stress markers decreased linearly with increasing
phenolic content. Mean changes for oxidized low-density lipoprotein levels
were 1.21 U/L (CI, -0.8 to 3.6 U/L), -1.48 U/L (-3.6 to 0.6 U/L), and -3.21
U/L (-5.1 to -0.8 U/L) for the low-, medium-, and high-polyphenol olive oil,
respectively. LIMITATIONS: The olive oil may have interacted with other
dietary components, participants' dietary intake was self-reported, and the
intervention periods were short. CONCLUSIONS: Olive oil is more than a
monounsaturated fat. Its phenolic content can also provide benefits for
plasma lipid levels and oxidative damage. International Standard Randomised
Controlled Trial number: ISRCTN09220811. PMID: 16954359

http://tinyurl.com/jjyfp


Also...

"CONCLUSIONS: Sustained consumption of virgin olive oil with the high
phenolic content was more effective in protecting LDL from oxidation and in
rising HDL cholesterol levels than that of other type of olive oils."

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=15168036
Eur J Nutr. 2004 Jun;43(3):140-7. Epub 2004 Jan 6.
Effects of differing phenolic content in dietary olive oils on lipids and
LDL oxidation--a randomized controlled trial.Marrugat J, Covas MI, Fito M,
Schroder H, Miro-Casas E, Gimeno E, Lopez-Sabater MC, de la Torre R, Farre
M; SOLOS Investigators.
Lipids and Cardiovascular Epidemiology, Research Unit, Institut Municipal
d'Investigacio Medica, Carrer Dr Aiguader 80, 08003 Barcelona, Spain.

BACKGROUND: Evidence from in vitro studies suggests that antioxidant olive
oil phenolic compounds can prevent LDL oxidation. However, in vivo evidence
in support of this hypothesis is sparse. AIM OF THE STUDY: to establish the
antioxidant effect of olive oils with differences in their phenolic
compounds content in humans METHODS: A controlled, double blind,
cross-over, randomized, clinical trial using three similar olive oils with
increasing phenolic concentration (from 0 to 150 mg/Kg) was conducted in 30
healthy volunteers. Olive oils were administered over three periods of 3
weeks preceded by two-week washout periods. RESULTS: Urinary tyrosol and
hydroxytyrosol increased (p < 0.020), in vivo plasma oxidized LDL decreased
(p = 0.006), and ex vivo resistance of LDL to oxidation increased (p =
0.012) with the phenolic content of the olive oil administered. After
virgin olive oil administration, an increase (p = 0.029) was observed in
HDL cholesterol levels. CONCLUSIONS: Sustained consumption of virgin olive
oil with the high phenolic content was more effective in protecting LDL
from oxidation and in rising HDL cholesterol levels than that of other type
of olive oils. Dose-dependent changes in oxidative stress markers, and
phenolic compounds in urine, were observed with the phenolic content of the
olive oil administered. Our results support the hypothesis that virgin
olive oil consumption could provide benefits in the prevention of oxidative
processes.

PMID: 15168036 [PubMed - indexed for MEDLINE]



===

"Short-term consumption of olive oils decreased plasma oxidized LDL
(oxLDL), 8-oxo-dG in mitochondrial DNA and urine, malondialdehyde in urine
(P < 0.05 for linear trend), and increased HDL cholesterol and glutathione
peroxidase activity (P < 0.05 for linear trend), in a dose-dependent manner
with the phenolic content of the olive oil administered."

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=15333722&query_hl=2&itool=pubmed_docsum
J Nutr. 2004 Sep;134(9):2314-21.
Olive oils high in phenolic compounds modulate oxidative/antioxidative
status in men.Weinbrenner T, Fito M, de la Torre R, Saez GT, Rijken P,
Tormos C, Coolen S, Albaladejo MF, Abanades S, Schroder H, Marrugat J,
Covas MI.
Lipids and Cardiovascular Epidemiology Unit, Institut Municipal
d'Investigacio Medica, Barcelona, Spain.

The aim of the present study was to evaluate whether olive oils high in
phenolic compounds influence the oxidative/antioxidative status in humans.
Healthy men (n = 12) participated in a double-blind, randomized, crossover
study in which 3 olive oils with low (LPC), moderate (MPC), and high (HPC)
phenolic content were given as raw doses (25 mL/d) for 4 consecutive days
preceded by 10-d washout periods. Volunteers followed a strict very
low-antioxidant diet the 3 d before and during the intervention periods.
Short-term consumption of olive oils decreased plasma oxidized LDL (oxLDL),
8-oxo-dG in mitochondrial DNA and urine, malondialdehyde in urine (P < 0.05
for linear trend), and increased HDL cholesterol and glutathione peroxidase
activity (P < 0.05 for linear trend), in a dose-dependent manner with the
phenolic content of the olive oil administered. At d 4, oxLDL after MPC and
HPC, and 8-oxo-dG after HPC administration (25 mL, respectively), were
reduced when the men were in the postprandial state (P < 0.05). Phenolic
compounds in plasma increased dose dependently during this stage with the
phenolic content of the olive oils at 1, 2, 4, and 6 h, respectively (P <
0.01). Their concentrations increased in plasma and urine samples in a
dose-dependent manner after short-term consumption of the olive oils (P <
0.01). In conclusion, the olive oil phenolic content modulated the
oxidative/antioxidative status of healthy men who consumed a very
low-antioxidant diet.

PMID: 15333722 [PubMed - indexed for MEDLINE]

===
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Relevant Pages

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