Goede
olijfolie goed voor het hart.*
Volgens een Europese studie is olijfolie en dan in het bijzonder de extra virgin olijfolie, goed tegen hart- en vaatziektes. Uit eerdere studies is al gebleken dat olijfolie goed is voor het hart in deze studie is gekeken naar het verschil tussen extra virgin olijfolie en gewone olijfolie. Gebleken is dat extra virgin olijfolie veruit het beste is, veel groter stijging van het goede cholesterol (HDL) en daling van oxidatieschade. Het verschil in de soorten olijfolie is voornamelijk het verschil in polyfenolen, bioactieve stoffen die verantwoordelijk zijn voor de verschillen in eigenschappen. In extra virgin olijfolie zitten veruit de meeste bioactieve stoffen.
The
Effect of Polyphenols in Olive Oil on Heart Disease Risk Factors
A
Randomized Trial
María-Isabel Covas, MSc, PhD; Kristiina Nyyssönen, MSc, PhD; Henrik E.
Poulsen, MD, PhD; Jari Kaikkonen, MSc, PhD; Hans-Joachim F. Zunft, MD, PhD;
Holger Kiesewetter, MD, PhD; Antonio Gaddi, MD, PhD; Rafael de la Torre, MSc,
PhD; Jaakko Mursu, MSc; Hans Bäumler, MSc, PhD; Simona Nascetti, MD, PhD; Jukka
T. Salonen, MD, PhD; Montserrat Fitó, MD, PhD; Jyrki Virtanen, MSc; Jaume
Marrugat, MD, PhD, for the EUROLIVE Study Group
September 2006 | Volume 145 Issue 5 | Pages 333-341
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. 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.
Context
Olive oil, the main fat
in the Mediterranean diet, contains polyphenols, which have
antioxidant properties and may affect serum lipid levels.
Contribution
The authors studied
virgin olive oil (high in polyphenols), refined olive oil (low in
polyphenols), and a mixture of the 2 oils in equal parts. Two hundred
healthy young men consumed 25 mL of an olive oil daily for 3 weeks
followed by the other olive oils in a randomly assigned sequence.
Olive oils with greater polyphenol content increased high-density
lipoprotein (HDL) cholesterol levels and decreased serum markers of
oxidation.
(Sept. 2006) (Opm. Meer over olijfolie)