effect of olive oil and its phenolic compounds on reduction of heart disease risk factors and...
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EFFECT OF OLIVE OIL AND ITS PHENOLIC
COMPOUNDS ON REDUCTION OF HEART
DISEASE RISK FACTORS AND OXIDATIVE
DAMAGE
M.I. CovasLipids and Cardiovascular Epidemiology UnitInstitut Municipal d´Investigació Mèdica (IMIM). Barcelona. Spain
Sessions dels Groups i Unitats d´Epidemiologia. IMIM. Maig 2006
Background
The benefits of olive oil consumption are becoming increasingly recognized.
Recently, the FDA permitted a claim on olive oil labels concerning:
“the benefits on the risk of coronary heart disease (CHD) of eating about 2 tablespoons (23 grams) of olive oil daily, due to the monounsaturated fat
(MUFA) in olive oil”.
However, if the effect of olive oil can be attributed solely to is MUFA content, any
type of olive oil, rapeseed oil, or or MUFA-rich food would provide the same
health benefits.
Olive oil is the main source of fat in the Mediterranean Diet
Thus, Public Health implications exist as to whether a specific type of MUFA fat or
olive oil should be recomended as individualized eating strategies for oxidative stress
associated diseases prevention
OLIVE OIL COMPONENTS
• Major components: Fatty acids– Saturated (8-14%)– Monounsaturated (oleic acid 55-83%)– Poliunsaturated (4-20%)
• Minor components:– Squalene, Sterols, triterpenes– Vitamin E, Beta-carotene– Phenolic compounds (tyrosol, hydroxytyrosol,
oleuropeine, lignanes).
EUROPEAN OLIVE OIL MEDICAL INFORMATION LIBRARY
TYPES OF OLIVE OIL
OLIVES
LEAF REMOVAL
WASHING
CRUSHING-MILLING
PASTE MALAXATION
PRESSURE OR CENTRIFUGATION
VIRGIN OLIVE OILOLIVE POMACE
Refination
Orujo de oliva
Refination Refined olive oil
Mixture
Low phenolic content
(10-30 mg/Kg)
High phenolic content
(150-400 mg/Kg)
Low phenolic content
(10-70 mg/Kg)
Phenolic content (0-5 mg/kg)
Pomace olive oil Common olive oil
The phenolic content of an olive oil varies, depending on the cultivar, climate, ripeness of the olives at harvesting, and the processing system for the type of olive oil:
Background
Olive oil phenolic compounds show:
•strong antioxidant properties against free radical generation and LDL oxidation in experimental studies
• delayed the progression of atherosclerosis in animal models.
Oleate-rich LDL is less susceptible against oxidative modification than linoleate-rich LDL.
There is increasing evidence that dietary phenolic compounds can modulate lipid and lipoprotein metabolism.
Oxidative damage of deoxyribonucleic acid (DNA) is linked pathogenically to a
variety of diseases such as cancer and also to ageing
Low density lipoprotein (LDL) oxidation is a hallmark for atherosclerosis development.
Olive oil phenolic compounds are bioavailable in humans
Data regarding the benefits of olive oil phenolic compounds in humans
from real-life daily doses of olive oil are controversial and scarce
The protective effects on lipid oxidation in these trials being better displayed
in oxidative stress conditions
Carefully controlled studies in appropriate populations (i.e. oxidative stress
conditions, or with a large sample size (in the case of healthy volunteers), are
required to definitively establish the health properties of olive oil phenolic
compounds in humans.
Consensus report. Expert Panel
International Conference of Olive Oil and Health. Jaen, Spain October 2004
Expert Panel. Pérez-Jiménez, Coordinator, et al, Eur J Clin Invest 2005;35:421-4
THE EFFECT OF OLIVE OIL CONSUMPTION ON OXIDATIVE DAMAGE IN EUROPEAN
POPULATIONS. The EUROLIVE Study (QRLT-2001-00287)
Covas MI, Poulsen HE, Nyyssönen K, Zunft HFJ, Kiesewetter H, Gaddi A, López-Sabater C,
Kaikkonen J, on behalf of the EUROLIVE Investigators
IMIM
UBGL
KEPKA
DIfE
RHK
UKU
EUC
UB
JLB
UBER
Objective
To assess the effect of three similar types
of olive oil, but with differences in their
phenolic content, on blood lipids, and the
oxidative/antioxidative status in healthy
human volunteers.
3.1.1 Characteristics of the olive oils
Determination of phenolic content in several virgin olive oils (HPC)Virgin olive oil
Picual from Jaen (Andalucia, Spain, 366 ppm of PC)
Measurement of fatty acid profile and vitamin E
Determination of fatty acid profile and vitamin E of several refined virgin olive oils from similar cultivar and soil
(VLPC) Refined olive oil (similar characteristics to the virgin one)
Mixture
(MPC) Common olive oil
3.1 Protocol of management for Olive Oils
Characteristics of the Olive Oils Administered
Type of olive oil
750 430 580
Free acidity (% oleic acid) 0.03 0.08 0.18
Peroxide value (mEq O2/kg) 4.12 5.89 11.28
Fatty acids (%)
C14:0 0.01 0.01 0.01
C16:0 10.63 10.50 10.63
C16:1 0.88 0.86 0.88
C17:0 0.05 0.05 0.04
C17:1 0.09 0.09 0.09
C18:0 3.27 3.13 2.84
C18:1 79.08 79.80 80.60
C18:2 4.64 4.21 3.35
C20:0 0.39 0.39 0.35
C18:3 0.58 0.58 0.58
C20:1 0.26 0.25 0.25
C22:0 0.11 0.10 0.10
C24:0 0.01 0.02 0.02
-Tocopherol (ppm) 229 228 228
Phenolic compounds (mg/Kg) 2.7 164 366
Squalene (mg/g) 3.0 3.2 3.4
-sitosterol (mg/g) 1.4 1.5 1.5
The EUROLIVE Study
Study population: 200 healthy non-smoker males recruited between December 2002 and July 2003 in 6 Centers of 5 European Countries (Denmark, Finland, Germany (2 Centres), Italy, and Spain).
The EUROLIVE Study. Methods
Eligibility criteria: to be healthy on the basis of clinical exanimation and laboratory analyses; willingness to provide written, informed consent; and to agree to the adherence to the protocol
Exclusion criteria: -smoking -intake of antioxidant supplements
- diabetes - hypertension
-Hyperlipidaemia - any condition limiting mobility
-obesity (body mass index >30 kg/m2)
-aspirin, or drugs with established antioxidant properties
-celiac or other intestinal disease, life-threatening diseases, or any other disease or condition that would impair compliance.
Persons invited to be screenedn = 344
144 ineligible 98 Did Not Met Protocol criteria 46 Unwilling to Participate
68 Assigned to Order 2,
(MPC, LPC, HPC)
200 Randomized
67 Assigned to Order 1,
(HPC, MPC, LPC) 65 Assigned to Order 3
(LPC, HPC, MPC)
6 Out of Follow-up
3 Unable to adhere
2 Moved away
1 Collateral event
5 Out of Follow-up
2 Unable to adhere
2 Moved away
1 Collateral event
7 Out of Follow-up
4 Unable to adhere
1 Moved away
2 Collateral events
61 Included in the Analysis 63 Included in the Analysis 58 Included in the Analysis
Flow-chart describing progress of participants through the EUROLIVE Study
LPC, MPC, and HPC, olive oils with low, medium and high phenolic content, respectively.
The EUROLIVE Study. Methods
Latin Square for three treatments in the cross-over clinical trial
Examination Number: 1 2 3 4 5 6 7 Blood collection Anthropometric measures
Order 1
HPC WO MPC WO LPC
Order 2
WO MPC WO LPC WO HPC
Order 3 WO LPC WO HPC WO MPC
LPC, MPC, and HPC: olive oils with low, medium, and high phenolic content
WO: wash-out period, (2 weeks) .Intervention periods 3 weeks (25 mL/day olive oil ingestion
Examination number (general measurements and/or blood collection): 1, baseline; 2, post-first washout; 3, post-first
intervention;
4, post-second washout; 5, post-second intervention; 6, post-third washout; 7, post-third intervention .
3DDR 3DDR 3DDR 3DDR
FHD/PA PA
The EUROLIVE Study. Methods
WO
Outcome measurements in the Clinical Trials
Urinary tyrosol and hydroxytyrosol, the major olive oil phenolic compounds, as markers of compliance
Oxidative markers
Lipid oxidation
F2 isoprostanes (pl)
OH-Fatty acids (pl)
Conjugated dienes (LDL)
Oxidized LDL (pl)
Antibodies against oxidized LDL (s))
DNA and RNA oxidation
8-oxo-dGuo (u)
8-oxo-Guo(u)
8-oxo-Gua (u)
Antioxidative markers
Endogenous
SOD (b)
GSH-Px (pl)
GR (pl)
GSH/GSSG (b)
Enterolactone (s)
PON (s)
Exogenous
AA (pl)
Tocopherol (pl)
-carotene (pl)
Lycopene (pl)
Lipid status: Fatty acids in LDL; Serum Cholesterol, LDL, HDL
The EUROLIVE Study. Methods
3-O-methyl-hydroxytyrosol in urine as a marker of the individual bioavailability and metabolic capacity of the hydroxytyrosol ingested.
No differences at baseline were observed among the three groups of olive oil administration order:
•For energy, macronutrients, or for the main antioxidant (vit E, beta-carotene...) or pro-oxidant intake (iron).
•For the evaluated end-points, with the exception of low levels of Ab-oxLDL in order 1 group and 8-dGuo in order 3 group (P<0.05).
The EUROLIVE Study. Results
No carryover effect, examined through the interaction treatment by period in the models, was observed for any outcome.
No changes in daily energy expenditure in leisure time physical activity were observed from the beginning to the end of the study (mean values, 282 vs 275 kcal/day).
Diet was similar in the three groups during each type of olive oil administration.
Mean daily energy consumption (SD) and selected nutrient intake (SD) according olive oil intervention
Olive Oil
Nutrient Low phenolics Medium phenolics
High phenolics
Energy (kcal)
2212
(690.6)
2228
(741.4)
2245
(650.0)
Carbohydrate (%)* 48.4 (27.6) 46.2 (9.5) 46.3 (9.3)
Protein (%)* 15.3 (3.3) 15.6 (3.7) 15.4 (3.6)
Total Fat (%)* 36.2 (8.1) 36.2 (8.1) 36.1 (8.2)
Saturated fat (%)* 12.6 (3.5) 12.6 (3.5) 12.8 (3.6)
Monounsaturated fat (%)* 14.6 (4.4) 14.7 (4.7) 14.7 (4.6)
Polyunsaturated fat (%)* 4.9 (2.0) 4.9 (1.9) 4.8 (1.9)
Vitamin C (mg) 102 (71.4) 104 (73.2) 115 (96.5)
Vitamin E (mg) 9.2 (4.8) 9.2 (5.6) 8.9 (4.9)
ß-carotene (mg) 2.4 (2.6) 2.6 (3.0) 2.2 (2.3)
*Expressed in percentage of total energy intake
The EUROLIVE Study. Results
Changes in total fat after intervention periods
Post-HPCPost-MPCPost-LPCBaseline
To
tal f
at (
g)
110
100
90
80
* * *
* P < 0.001, Tukey´s test
The EUROLIVE Study. Results
LPC, MPC, and HPC, olive oils with low, medium and high phenolic content, respectively.
Changes in carbohydrate intake after intervention periods
The EUROLIVE Study. Results
Post-HPCPost-MPCPost-LPCBaseline
Car
bo
hyd
rate
inta
ke (
g/d
ay)
290
280
270
260
250
240
*
*P < 0.001, Tukey, t test
LPC, MPC, and HPC, olive oils with low, medium and high phenolic content, respectively.
P < 0.001 for linear trend; * P< 0.05 versus LPC, † P< 0.001 versus MPC
2000
Ch
ange
(%
)
3000
2500
2000
1500
1000
500
0
Hydroxytyrosol * †
*
Type of olive oil administered
HPCMPCLPC
Ch
ange
(%
) 1500
1000
500
0
Tyrosol* †
*
The EUROLIVE Study. Results-Urinary tyrosol and hydroxytyrosol as markers of Compliance
LPC, MPC, and HPC, olive oils with low, medium and high phenolic content, respectively.
LPC
Olive oil intervention
MPC
HPC
Post-int Change Post-int Change Post-int Ghange
Body mass index (kg/m 2) 24.1 (2.8) 0.03 (0.31) 24.1 (2.8) 0.05 (0.33)) 24.0 (0.21) 0.01 (0.30)
SBP(mmHg) 123 (0.88) 122 (0.95) 123 (0.89) 123 (0.85) 123 (0.82) 123 (0.93)
DBP (mmHg) 75 (0.65) 76 (0.64) 76 (0.68) 76 (0.60) 76 (0.62) 76 (0.65)
Glucose (mg/dL) 86 (6.6) -0.29 (0.8) 86 (7.2) -0.29 (8.5) 86 (5.9) -0.08 (11.2)
Cholesterol (mg/dL)
Total 182 (37) 0.21 (21) 181 (36) 0.51 (24) 183 (37) 0.50 (17)
LDL 115 (34) 0.55 (19) 113 (33) -0.88 (21) 2115 (34) -0.41 (18)
HDL 49.2 (10.8) 0.99 (6.1) * 49.6 (10.3) 1.23 (6.5)* 50.4 (11.1) 1.76 (5.3)‡
Triglycerides (mg/dL) 91 (37) -6.1 (37) * 92 (37) -5.0 (41) 91 (32)
1.76 (5.3)‡1.23 (6.5)*0.99 (6.1)*
-6.1 (37)* -5.0 (41)
The EUROLIVE Study. ResultsThe EUROLIVE Study. Results
P for linear trend2
0.55
0.12
0.78
0.27
0.31
0.68
0.90-4.7 (32)*-4.7 (32)*
0.018
Total Cholesterol/HDL 3.88 (1.11) -0.09 (0.58) 3.81 (1.06) -0.10 (0.55) 3.81 (1.07) -0.12 (0.50) 0.005
LDL/HDL ratio 2.46 (0.95) -0.05 (0.49) 2.38 (0.88) -0.07 (0.49) 2.41 (0.93) -0-09 (0.45) 0.052 -0-09 (0.45) †
-0.10 (0.55) † -0.012 (0.50)*
-0.07 (0.49)*
0.018
0.005
0.052
Changes1 in Body Weight, Systolic and Diastolic Blood pressure, Glucose, and Blood Lipids after intervention with olive oil with high (HPC), medium (MPC), and low ( LPC) phenolic content (mean (SD).
1 General linear model, * P < 0.05; P<0.01, ‡ P < 0.001 versus the corresponding baseline, Tukey´s test. 2 General linear model with post-intervention values adjusted by baseline values.
-0.09 (0.58)†
LPC
Olive oil intervention
MPC
HPC
Post-int Change Post-int Change Post-int Change
F2-isoprostanes ( g/L)
28 (4.9) 0.15 (4.9) 28 (4.3) -0.31 (5.4) 28 (6.4) 0.08 (5.3)
Uninduced dienes (mol/mol chol)
2.60 (0.96) -0.03 (0.83)
2.57 (0.92) -0.20 (0.91) ‡
2.50 (0.91) 0.18 (0.78) †
Hydroxyfatty acids (mol/L)
1.26 (0.18) -0.03 (0.51)
1.25 (0.18) -0.06 (0.49)
1.21 (0.17) 1.22 (0.026)*
8-oxo-deoxyguanosine (nmol/24h-urine)
18.6 (0.63) -2.3 (0.75) ‡
17.9 (0.53) -2.9 (0.50) ‡
18.1 (0.57) -2.1 (0.55) †
8-oxo-guanosine (nmol/24h-urine)
21.6 (0.74) 0.9(0.76)
21.0 (0.72) 0.4 (0.71)
21.5 (0.74) 0.3 (0.81)
8-oxo-guanine (nmol/24h-urine)
121 (6.5) 28 (13)
160 (14.9) 25 (7.8)
152 (9.6) 24 (14.3)
-
-2.9 (0.50)‡
-0.20 (0.91) † -0.18 (0.78) †
-0.08 (0.49) †
-2.3 (0.75)‡ -2.1 (0.55)†
The EUROLIVE Study. ResultsThe EUROLIVE Study. Results
P for linear Trend2
0.23
Antibodies against 3
oxidized LDL (U/L) 590 (234;1397)
-0.20 (-80 ; 85)
636 (228;1416)
9.8 (-61; 153)
557 (240;1403)
8.3 (-67 ;116)
0.60
0.001
0.004
0.16
0.23
0.39
Oxidized LDL (U/L) 47 (18) 0.94 (17) 46 (16) -1.85 (14) 45 (16) 45.7 (1.8)*
-3.5 (15) † 0.0140.014
0.001
0.004
1 General linear model, ‡ P<0.01, ‡ P < 0.001 versus the corresponding baseline, Tukey´s test. 2 General linear model with post-intervention values adjusted by baseline values. 3 median (25th-75th percentile)
Changes1 in oxidative stress biomarkers after intervention of olive oil with high (HPC), medium (MPC), and low (LPC) phenolic content (mean (SD)
LPC
Olive oil intervention
MPC
HPC
Post-int Change Post-int Change Post-int Change
Endogenous
Paraoxonase (U/L) 165 (113) 0.27 (33) 164 (109) 0.13 (28) 165 (113) -2.46 (25)
.
Superoxide dismutase (U/L) 142 (20) -0.47 (14) 141 (20) -1.50 (13) 142 (20) 0.12 (14)
Glutathione peroxidase (U/L) 708 (152) -2.3 (119) 704 (134) -1.1 (106) 714 (162) -3.7 (126)
Glutathione reductase (U/L) 62 (10) -1.9 (18) 63 (10) -1.6 (19) 63 (11) 0.78 (20)
Reduced glutathione (mol/L) 5.85 (0.64) 0.31 (0.40) ‡ 5.85 (0.67) 0.28 (0.32)‡ 5.87 (0.56) 0.33 (0.38)‡
Oxidized glutathione (mol/L) 0.84 (0.18) -0.12 (0.17) ‡ 0.82 (0.19) -0.14 (0.16) ‡ 0.83 (0.17) -0.12 (0.18) ‡
Red/Ox glutathione ratio 7.9 (2.2) 1.74 (2.9) ‡ 8.2 (2.6) 2.0 (3.4) ‡ 8.1 (1.6) 1.5 (3.7) ‡
-0.14 (0.16)‡
0.31 (0.40)‡ 0.28 (0.32)‡ 0.33 (0.38)‡
-0.12 (0.17)‡ -0.12 (0.18)‡
1.5 (3.7)‡2.0 (3.4)‡1.74 (2.9)‡
The EUROLIVE Study. ResultsThe EUROLIVE Study. Results
P for linear trend2
0.77
0.53
0.31
0.02
0.70
0.69
0.77
No changes in plasma exogenous antioxidants (vit C,vit E, -carot, Lycopene).
Changes1 in antioxidative biomarkers after intervention of olive oil with high (HPC), medium (MPC), and low (LPC) phenolic content (mean (SD)
1 General linear model, ‡ P < 0.001 versus the corresponding baseline, Tukey´s test. 2 General linear model with post-intervention values adjusted by baseline values, order and centre.
Paired comparisons among values after olive oils interventions
Mean of Differences (SEM)
Variable HPC vs LPC p MPC vs LPC p HPC vs MPC p
HDL Cholesterol (mg/dL) 1.93 (0.77) 0.012 0.71 (0.66) 0.283 1.22 (0.64) 0.045
Uninduced dienes (mol/L) -0.060 (0.02) 0.013 -0.036 (0.02) 0.084 -0.024 (0.02) 0.218
Oxidized LDL (U/L) -4.48 (1.73) 0.010-2.96 (1.48) 0.046 -1.52 (1.43) 0.288
The EUROLIVE Study. ResultsThe EUROLIVE Study. Results
0.012 0.045
0.013
0.010 0.046
GLMM adjusted by basal values for each intervention period, olive oil administration order,center, and age
Results improved when difference of fat and carbohidrate from baseline are added to the model.
Table 4. Changes after olive oil interventions by centre
Variable Centre 1(Barcelona)
(n =30)
Centre 2(Copenhagen)
(n =28)
Centre 3(Kuopio)
(n =30)
Center 4(Bologna)
(n = 25)
Center 5(Postdam)
(n = 38)
Center 6(Berlin)
(n =32)
HDL cholesterol, mg/dLLow PC olive oil
Medium PC olive oil
High PC olive oil
0.92 (-1.1 to 2.9)
1.38 (-0.08 to 2.8)
2.20 (0.58 to 3.8)
1.50 (-1.3 to 4.2)
3.63 (-0.7 to 7.9)
1.49 (-1.1 to 4.1)
0.93 (-1.1 to 2.9)
0.38 (-1.9 to 2.5)
1.73 (-0.2 to 3.7)
0.54 (-1.4 to 2.5)
0.11 (-2.2 to 2.4)
2.62 (0.2 to 5.0)
1.28(-1.1 to 3.7)
1.38 (-0.6 to 3.3)
2.58 (0.6 to 4.5)
0.20 (-1.3 to 1.7)
0.52 (-1.3 to 2.3)
0.58 (-1.8 to 2.9)
Oxidized LDL, U/LLow PC olive oil
Medium PC olive oil
High PC olive oil
3.38
(-2.6 to 9.4)-1.62
(-6.2 to 3.0)-3.10
(-6.9 to 0.8)
2.7
(-6.7 to 12)-2.87
(-10.3to 4.6)0.40
(-7.2 to 8.0)
-0.49
(-4.2 to 3.3)-1.93
(-5.9 to 2.1)-1.64
(-4.9 to 1.6)
2.30
(-4.6 to 8.7)-0.84
(-10.0to 9.8)-8.69
(-15.8 to-2.2)
-5.53
(-11.8 to 0.7)-2.12
(-6.6 to 2.4)-8.75
(-14.0 to –2.9)
2.26
(-2.7 to 7.2)-2.0
(-5.7 to 1.6)-2.28
(-5.7 to0.48)
Hydroxy fatty
acids,* nmol/L Low PC olive oil
Medium PC olive oil
High PC olive oil
10 (109 to 106)
-3 (-127 to 134)
-22 (-116 to 71)
40 (-86 to 166)
-13 (-124to 150)
-114 (-247 to 19)
33 (-75 to 141)
-19 (-130 to 93)
-65 (-195 to 65)
-45 (-222to 132)
-165 (-299 to -31)
-109 (-223 to -9)
-66 (-167 to 35)
14 (-87 to 114)
-14 (-85 to 56)
-130 (-273 to 13)
-69 (-189 to 30)
-76 (-174 to -4)
Consumption of 25 mL daily doses of all types of olive oil, as source of
raw fat, reduced lipid cardiovascular risk factors, improved the
glutathione antioxidant status, and decreased oxidative DNA damage
Consumption of the olive oil with the high phenolic content (virgin)
provided the highest benefits by increasing HDL cholesterol levels and
reducing the oxidative damage on lipids
Daily consumption of olive oils with medium and high phenolic content decreased oxidative damage on lipids.
The EUROLIVE Study. ResultsThe EUROLIVE Study. Comments
Changes in biomarkers were modest, as was expected for the
administration of real-life doses of a single food, during three weeks.
Our results supports the body of research concerning that a rich-MUFA
diet can help to reduce triglycerides and raise HDL cholesterol, in
accordance with current cardiovascular guidelines.
The EUROLIVE Study. Comments
Our finding suggest an independent effect of olive oil phenolics increasing HDL-cholesterol levels.
The enhancement of HDL-cholesterol related with the phenolic content
of the olive oil is in line with the results obtained after phenolic-rich
food conssumption in other human studies.
The EUROLIVE Study. Comments
Type of olive oil
HPCMPCLPC
Diff
ere
nce
in H
DL
(m
mm
ol/L
)
0.065
0.052
0.039
0.026
0.01
0.00
Threshold
A 0.026 mmol/L increase in circulating HDL cholesterol levels is associated with a decrease from 1 to 3.6% in cardiovascular mortality, and with a 3.7% reduction of the risk to develop acute myocardial infarction (Stampfer MJ et al. JAMA 1996; 276: 882-8).
Projected reduction in CHD risk associated with 25 mL olive oil
per day versus non olive oil consumption (%)
Type of olive oil
Biomarker Relative risk (95% CI)1 LPC MPC HPC
HDL-C 0.69 (0.47 to 0.99 per 10 mg/dL) 3.60 4.45 6.30
Triglycerides 1.33 (1.05 to 1.68 per 100 mg/dL) 1.72 1.41 1.33
1 From Jacobs DR et al. Am J Epidemiol 1990; 131: 32-47 and Stampfer MJ et al. JAMA 1996; 276: 882-888.
LPC, MPC, and HPC, olive oils with low (14.7 mg/Kg), medium (164 mg/Kg), and high (366 mg/Kg) phenolic content, respectively.
These risk decrements were based upon data from cohort
studies. Whether a HDL or triglycerides reduction due to
olive oil and its phenolic consumption would lead to these
decreases in CHD risk has not been established.
Oxidative damage to lipids decreased in a linear form with the phenolic content of
olive oil, particularly in those markers directly associated with LDL oxidation.
Oxidation of the lipids present in LDL (measured by conjugated dienes and
hydroxy fatty acids) or direct oxidation of the LDL protein led to a change into
the lipoprotein conformation (measured by the levels of oxidized LDL) by which
the LDL is more able to enter in the monocyte/macrophage system, inside the
arterial wall, and promote the atherosclerotic process.
Circulating ox-LDL levels show a positive relationship with the severity of
acute coronary syndromes and are biomarkers for CHD risk.
The EUROLIVE Study. Comments
Mechanisms involved could be the own antioxidant activity of the phenolic compounds and the combined protective effect of both the phenolic and the
MUFA content of the olive oil
Phenolic compounds in LDL
Levels of oleic acid and antioxidants in LDL after sustained (1 week, 25ml/day) doses of virgin olive oil
8.5n
g/m
g p
rote
in
7.0
5.5
4.0
Baseline Post-intervention
†10
8.5
g/m
g p
rote
in
7.0
5.5
4.0Vit E in LDL
†10
*
Oleic acid in LDL
2220
1816
14
Gimeno et al. Eur J Clin Nutr 2002; 56:114-120
12
% o
f T
otal
fat
22
The susceptibility of LDL to
oxidation depends not only
on its fatty content, but also
of the LDL content of
antioxidants, such as vitamin
E and phenolic compounds (Fuller CJ, Jialal I. Am J Clin Nutr.
1994; 60:1010-3).
B
a
Olive oil intervention
HPCMPCLPC
60
40
20
0
-20
-40
Ch
ang
e (
%)
fro
m b
asel
ine 80
60
40
20
0
-20
-40
A
a
HPCMPCLPC
Olive oil intervention
Changes in the total phenolic content of the LDL are modulated by olive oil
phenolic compounds
at 1h (A), and after 4 days (B) of 25 mL/day consumption of olive oils with high (HPC, 360
mg/Kg), medium (164 mg/Kg), and low (2.7 mg/Kg) phenolic content
P = 0.032 for linear trend P = 0.042 for linear trend
a P< 0.05 versus LPC
Covas MI et al. Free Rad Biol Med 2006
Hydroxytyrosol in plasma (g/L)403020100C
hang
e (%
) of
PC
in L
DL
200
100
0
-100
R = 0.780, P = 0.009A
Tyrosol in plasma (g/L)181614121086
Cha
nge
(%)
of P
C
in L
DL
300
200
100
0
-100
R = 608, P = 0.036B
R = 0.699, P = 0.011
Tyrosol in plasma (g/L)2220181614121086
Cha
nge
(%)
of P
C in
LD
L
400
300
200
100
0
-100
C
Relationship between tyrosol and hydroxytyrosol in plasma and changes in the LDL phenolic content
Covas MI et al. Free Rad Biol Med 2006
Projected reduction in CHD risk associated with 25 mL olive
oil per day versus non olive oil consumption
After HPC olive oil a mean decrease of –3.2 U/L in oxidized
LDL was observed
Although several studies reported a direct relationship between oxidized
LDL and CHD risk, the attributable CHD risk associated with a 1U/L
change of oxidized LDL is, at present, unknown.
In a recent study, the mean difference, in circulating oxidized LDL values
between CHD patients and healthy controls, measured using the same
antibody and method as in the present study, was 17 U/L.
Limitations of the study
The EUROLIVE Study. Comments
Inability to determine whether an interaction between olive oil components and others from diet could account for the changes in cardiovascular risk factors observed, which might affect the generalizability of the results due to dietary differences among countries.
The overall inter-country consistency of the results, however, contributes to the generalizability of the message.
Our design, did not allow modeling the first- and second-order possible
carryover effects. The measurements of dietary intake relied on self-reporting and were therefore subjective.
Although the trial was blinded, some participants might have identified the low phenolic olive oil (LPC) or the high phenolic content (HPC) by their color and taste and, not liking them, masking a lack of full compliance despite a good overall compliance.
Consumption of all types of olive oil provide benefits on the cardiovascular risk profile, antioxidant endogenous defences (GSH), and oxidative DNA damage, without modifying levels of antioxidant endogenous enzymes.
The results of the study show that olive oil is more than a MUFA fat.
The phenolic content of an olive oil can account for greater benefits on blood lipids and oxidative damage than those provided by the MUFA content of the olive oil.
The results of the EUROLIVE study provide evidence to recommend the use of olive oil rich in phenolic compounds as a source of fat in order to achieve additional benefits against cardiovascular risk factors.
The EUROLIVE Study. ConclusionsThe EUROLIVE Study. Conclusions
Recommendations which stem from the EUROLIVE study are:
• Among the olive oils with a taste that better suits personal preferences, the best choice is that with the highest phenolic content.
• For health policy makers, the phenolic content of an olive oil should be present in the olive oil labels.
The EUROLIVE Study. ConclusionsThe EUROLIVE Study. Recommendations
Olive oils with high phenolic content are stronger, and, in general more bitter and greener than those with low phenolic content.
Olive oil must not be taken as a medicine.
Daily consumption of high phenolic olive oil did not compromise the endogenous antioxidant enzymes. In some studies, polyphenol-rich food and antioxidant supplementation led to a decrease in these enzymes, presumably due to a lack of activation of their production by the decrease in free radicals.
This decrease has been considered a negative effect in situations of free radical
production, such as exercise, in which the role of the antioxidant enzymes is
crucial in counteracting oxidative damage
The absence of changes in plasma antioxidant vitamins suggests an
independent effect of phenolic compounds from olive oil on oxidative
damage.
The EUROLIVE Study
THE EFFECT OF OLIVE OIL CONSUMPTION ON OXIDATIVE DAMAGE IN EUROPEAN
POPULATIONS. The EUROLIVE Study
IMIM
UBGL
KEPKA
DIfE
RHK
UKU
EUC
UB
JLB
UBER
EUROLIVE Investigators:
Institut Municipal d´Investigació Mèdica (IMIM), Barcelona, Spain:
Lipids and Cardiovascular Epidemiology Research Unit: Covas MI (Study Coordinator), Marrugat J, Fitó M, Elosua R, Schröder H, Vila J. Cladellas M.
Pharmacology Research Unit, de la Torre R, Farré-Albaladejo M.
Department of Clinical Pharmacology, Rigshospitalet, University Hospital Copenhagen, Denmark:
Poulsen H E (Centre Coordinator), Weimann A.
Research Institute of Public Health, University of Kuopio, Finland: Salonen JT (Centre Coordinator), Konttinen A, Nyyssönen K Mursu J; Rissanen T, Tuomainen T-P, Valkonen V-P, Virtanen J.
Centro per lo Studio dell'Arteriosclerosi e delle Malattie Dismetaboliche"GC Descovich". Dipartimento di Medicina Clinica e Biotecnologia Applicata.Policlinico S. Orsola-Malpighi, Bologna, Italy: Gaddi A (Centre Coordinator), D’Addato S, Fiorito A, Grandi E, Linarello S, Nascetti S, Sangiorgi Z
German Institute of Human Nutrition Potsdam-Rehbruecke, Germany: Zunft, H-J F (Centre Coordinator), Koebnick C, Machowetz A
Institute of Transfusion Medicine, Charité-University Medicine of Berlin, Germany:
Kiesewetter H (Centre Coordinator), Bäumler H
Department of Nutrition and Bromatology. University of Barcelona, Spain:
López-Sabater C, Lamuela-Raventós R, de la Torre K,
Castellote AI
Oy Jurilab, Kuopio, Finland:
Kaikkonen J
oxldl post- MPC intervention interven (U/L)
120100806040200
Ab-
oxL
DL
po
st-M
PC
inte
rve
ntio
n (
U/L
)
6000
5000
4000
3000
2000
1000
0
-1000
oxldl post- LPC intervention (U/L)
140120100806040200
Ab-
oxL
DL
po
st-
LP
C in
terv
en
tion
(U/L
)
7000
6000
5000
4000
3000
2000
1000
0
-1000
oxLDL at baseline (U/L)
120100806040200
Ab-o
xLD
L a
t baseline (
U/L
) 6000
5000
4000
3000
2000
1000
0
-1000
oxLDL post- HPC intervention (U/L)
140120100806040200
Ab-o
xld
l post-
HP
C inte
rvention (
U/L
)
6000
5000
4000
3000
2000
1000
0
-1000
R = -0.264, P < 0.001
R = -0.210, P =0.005
R = -0.201, P =0.007
R = -0.213, P =0.004
The EUROLIVE Study. Results
Antioxidative Biomarkers after HPC, MPC, and LPC intervention periods
Exogenous
Ascorbic acid (mol/L) 62 (1.6) 62 (1.6) 61 (1.7) 59 (1.6) 61 (1.7) 61 (1.5)
-tocopherol (mol/L) 25 (0.48) 25 (0.47) 25 (0.49) 25 (0.48) 25 (0.48) 25 (0.48)
-carotene (mol/L) 0.41 (0.024) 0.38 (0.020) 0.40 (0.021) 0.41 (0.026) 0.42 (0.027) 0.40 (0.023)
Lycopene (mol/L) 0.45 (0.017) 0.44 (0.017) 0.43 (0.016) 0.45 (0.017) 0.45 (0.017) 0.44 (0.015)
Enterolactone (mol/L) 17 (1.6) 20 (1.9) 17 (1.5) 21 (2.3)* 17 (1.5) 18 (1.4)
Enterodiol (mol/L) 3.3 (1.2) 3.7 (0.89) 2.2 (0.50) 5.9 (1.9)* 2.7 (0.72) 2.8 (0.73)
Values are mean (SEM), except for antibodies against oxidized LDL which are expressed in median (25th -75th percentile).
Models adjusted by order of administration of olive oil and tyrosol post -intervention values.
*P < 0.05 versus the corresponding baseline, Tukey´s test
Pre-int Post-int Pre-int Post-int Pre-int Post-int
LPC MPC HPC
Olive oil intervention
5.9 (1.9)*
21 (2.3)*
The EUROLIVE Study. ResultsThe EUROLIVE Study. Results
*80
60
40
20
0
-20-40
*
A
Olive oil intervention
HighPCMedium PCLow PC
Ch
an
ge
(n
g/g
FA
) f
rom
ba
se
lin
e
60
40
20
0
-20
-40
B
Changes in the phenolic content of the LDL after a single dose of 40 mL (A) and after sustained
doses (25 mL/day, 4 days) of similar olive oils but with differences in their phenolic content
(PC)
Basal characteristics, glucose, lipid profile, and oxidative stress biomarkers at the beginning of the study by subgroups of order of olive oil administration according to an intent-to treat analyis.
Order 1(n=67)
Order 2(n=68)
Order 3(n=65)
Age (years) 33.4 (11.2) 34.3 (11.0) 31.9 (10.8)
BMI (Kg/m2) 23.7 (2.8) 23.8 (2.5) 24.0 (3.2)
Physical activity (kcal/day) 312 (250) 294 (248) 288 (207)
Systolic blood pressure (mmHg) 125 (14.4) 125 (11.1) 123 (12.7)
Diastolic blood pressure 77 (7.6) 78 (8.2) 76 (8.5)
Total cholesterol (mmol/L) 4.84 (0.96) 4.77 (1.06) 4.61 (1.09)
LDL cholesterol (mmol/L) 3.11(0.93) 3.08 (0.93) 2.95 (0.98)
HDL cholesterol (mmol/L) 46.9 (11.3) 46.4 (10.3) 48.5 (11.9)
Triglycerides (mmol/L) 102 (53) 1.2 (0.4) 1.0 (0.5)
Glucose (mmolL) 85 (9.4) 86 (10.4) 86 (9.4)
Oxidized LDL (U/L) 51 (26) 49 (20) 48 (22)
Antibodies against oxidized LDL (U/L) * 787 (120)* 1104 (153) 1092 (149)
Hydroxyfatty acids (mol/L) 1.3 (0.33) 1.35 (0.46) 1.30 (0.57)
F2-isoprostanes (g/L) 30.6 (5.8) 29.1 (5.9) 31.6 (7.6)
Uninduced dienes (mol/L) 11.3 (3.6) 11.4 (3.0) 12.1 (3.7)
8-oxo-deoxyguanosine (nmol/24h) 22.4 (8.2) 20.9 (8.0) 17.6 (6.6)*
8-oxo-guanosine (nmol/24h) 23.1 (9.5) 22.5 (8.4) 20.0 (8.6)
8-oxo-guanine (nmol/24h) 158 (100) 137 (84) 123 (92)
Values are men (SD). Order 1, High, medium , and low phenolic content olive oil; Order 2, medium, low, and high phenolic content olive oil; Order 3,low, high, and medium
phenolic content olive oil.. *P < 0.05 versus order 1 group.
The EUROLIVE Study. Results
Antioxidant status at the beginning of the study by subgroups of subjects depending on the order of olive oil administration according to an intent-to treat analysis
Order 1(n=61)
Order 2(n=63)
Order 3(n=58)
Endogenous
Superoxide dismutase (U/L) 142 (21) 144 (22) 140 (19)
Glutathione peroxidase (U/L) 719 (183) 686 (133) 692 (184)
Glutathione reductase (U/L) 64 (17) 64 (16) 64(16)
Reduced glutathione (GSH) (mol/L) 4.71 (0.59) 4.53 (0.57) 4.61 (0.72)
Oxidized glutathione (GSSG) (mol/L) 1.24 (0.12) 1.26 (0.12) 1.24 (0.12)
GSH/GSSG ratio 3.85 (0.62) 3.61 (0.57) 3.74 (0.71)
Paraoxonase 150 (95) 150 (90) 198 (142)
Exogenous
Ascorbic acid 61 (26) 60 (23) 62 (23)
-tocopherol (mol/L) 25.6 (5.7) 24.6 (6.3) 24.2 (6.8)
-carotene (mol/L) 0.45 (0.39) 0.40 (0.28) 0.35 (0.25)
Lycopene (mol/L) 0.46 (0.23) 0.42 (0.20) 0.43 (0.22)
Enterolactone (nmol/L) 16.8 (18.1) 22.6 (24.9)* 21.8 (36.6)
Enterodiol (nmol/L) 1.51 (5.30) 1.54 (4.13) 2.60 (9.6)
Order 1, high, medium , and low phenolic content olive oil; Order 2, medium, low, and high phenolic content olive oil; Order 3,low, high, and medium phenolic content olive oil.
The EUROLIVE Study. Results
Hydroxytyrosol (ug in 24h urine)
500040003000200010000-1000
F2
iso
pro
sta
ne
s (n
g/L
) 50
45
40
35
30
25
20
15
R =- 0.200, P < 0.01
Inverse relationship between plasma F2-isoprostanes and hydroxytyrosol in urine after high
phenolic content olive oil (HPC) intervention period. Spearman´s correlation
Statistical analyses •Normality of continuous variables was assessed by normal probability plots.
•One-factor ANOVA and Kruskal-Wallis test were used to determine differences in basal characteristics
and nutrient intake among the three olive oil interventions.
•A general linear model for repeated measurements was used, with multiple paired comparisons corrected
by Tukey´s method, in order to assess differences among post-intervention values adjusted by baseline
values.
•The paired comparison of target concentrations post-intervention was carried out by a General Linear Mixed Model (GLMM) with :
•Random effect: individual level of test subjects
•Fixed factor: the olive oil phenolic dose (high, medium, low) administered
•Covariates: basal values for each intervention period , olive oil administration order, age, difference of fat and carbohydrate intake from baseline.
•An additional model with adjustment for 3-O-methyl, hydroxytyrosol levels was also fitted
The EUROLIVE Study. Methods
Statistical significance was defined as P < 0.05 for a two-sided test. Analyses were performed using the SAS System for Windows release 8.02.