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Reheated Palm Oil Consumption and Risk of Atherosclerosis: Evidence at Ultrastructural Level

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Background. Palm oil is commonly consumed in Asia. Repeatedly heating the oil is very common during food processing. Aim. This study is aimed to report on the risk of atherosclerosis due to the reheated oil consumption. Material and Methods. Twenty four male Sprague Dawley rats were divided into control, fresh-oil, 5 times heated-oil and 10 times heated-oil feeding groups. Heated palm oil was prepared by frying sweet potato at 180 degrees C for 10 minutes. The ground standard rat chows were fortified with the heated oils and fed it to the rats for six months. Results. Tunica intima thickness in aorta was significantly increased in 10 times heated-oil feeding group (P < 0.05), revealing a huge atherosclerotic plaque with central necrosis projecting into the vessel lumen. Repeatedly heated oil feeding groups also revealed atherosclerotic changes including mononuclear cells infiltration, thickened subendothelial layer, disrupted internal elastic lamina and smooth muscle cells fragmentation in tunica media of the aorta. Conclusion. The usage of repeated heated oil is the predisposing factor of atherosclerosis leading to cardiovascular diseases. It is advisable to avoid the consumption of repeatedly heated palm oil.
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Hindawi Publishing Corporation
Evidence-Based Complementary and Alternative Medicine
Volume 2012, Article ID 828170, 6pages
doi:10.1155/2012/828170
Research Article
Reheated Palm Oil Consumption and Risk of Atherosclerosis:
Evidence at Ultrastructural Level
Tan Kai Xian,1Noor Azzizah Omar,1Low Wen Ying,1Aniza Hamzah,1Santhana Raj,2
Kamsiah Jaarin,3Faizah Othman,1and Farida Hussan1
1Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abd Aziz,
50300 Kuala Lumpur, Malaysia
2Institute of Medical Research, Ministry of Health, Jalan Raja Muda Abd Aziz,
50300 Kuala Lumpur, Malaysia
3Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abd Aziz,
50300 Kuala Lumpur, Malaysia
Correspondence should be addressed to Farida Hussan, khinpapah@gmail.com
Received 19 October 2012; Accepted 29 November 2012
Academic Editor: Kashmira Nanji
Copyright © 2012 Tan Kai Xian et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background. Palm oil is commonly consumed in Asia.Repeatedly heating the oil is very common during food processing. Aim. This
study is aimed to report on the risk of atherosclerosis due to the reheated oil consumption. Material and Methods. Twenty four male
Sprague Dawley rats were divided into control, fresh-oil, 5 times heated-oil and 10 times heated-oil feeding groups. Heated palm
oil was prepared by frying sweet potato at 180C for 10 minutes. The ground standard rat chows were fortified with the heated
oils and fed it to the rats for six months. Results. Tunica intima thickness in aorta was significantly increased in 10 times heated-oil
feeding group (P<0.05), revealing a huge atherosclerotic plaque with central necrosis projecting into the vessel lumen. Repeatedly
heated oil feeding groups also revealed atherosclerotic changes including mononuclear cells infiltration, thickened subendothelial
layer, disrupted internal elastic lamina and smooth muscle cells fragmentation in tunica media of the aorta. Conclusion. The usage
of repeated heated oil is the predisposing factor of atherosclerosis leading to cardiovascular diseases. It is advisable to avoid the
consumption of repeatedly heated palm oil.
1. Introduction
Palm oil is one of the commonly consumed oils in Malaysia.
It contains 50% unsaturated fat and 50% saturated fat
[1]. Consumption of saturated fat is believed to predispose
cardiovascular disease. However, fresh palm oil contains
tocopherols and tocotrienols which are antioxidants and
the antioxidant eect of tocotrienols is 40–60 times higher
than that of tocopherols [2]. Frying is one of the common
methods to prepare Asian food. Therefore, the consumed fats
in our diet are exposed to extreme temperature during cook-
ing. Furthermore, the practice of reusing oils for repeated
frying is also prevalent in an attempt to save cost. Repeated
heating increases lipid peroxidation and reduces antioxidant
properties of the oils, leading to produce free radicals [3].
Moreover, free radical induced oxidative stress is associated
with the atherosclerosis development [4]. Therefore, the
ingestion of repeatedly heated oil might produce harmful
eect, attributing to the development of atherosclerosis.
Atherosclerosis is a chronic progressive disease which
commonly aects arteries, resulting in reduced blood
flow that eventually predisposes to various ailments such
as coronary artery disease and cerebrovascular disease.
Atherosclerosis is prevalent in all over the world. It has
been proven that nutrition and cholesterol intake in the diet
are ranked as the highest risk factors in atherosclerosis [5].
The incidence of the disease is usually associated with the
circulating low-density lipoprotein (LDL). Polyunsaturated
fatty acid residues in lipoprotein are vulnerable to free radical
oxidation and these modified oxidative LDLs are scavenged
by the macrophage, forming the cholesterol laden “foam-
cells” in the atherosclerotic plaques [4]. Furthermore, these
2 Evidence-Based Complementary and Alternative Medicine
LDLs are chemoattractants for macrophage and smooth
muscle cells [6]. The atheromatous plaques formation might
be related to the growth factor action and angiogenesis
property of vasoactive small molecules produced by the
mast cells [7]. Therefore, cholesterol laden macrophage,
mononuclear cells migration, and migratory smooth muscle
cells in tunica media are expected to reveal in atherosclerotic
plague at ultrastructural level. The present study aimed
to highlight the impact on the cardiovascular health by
consumption of reheated palm oil and review the literature
on the mechanism of development of atherosclerosis.
2. Materials and Methods
The aortic samples of this study were obtained from the
previous research conducted by the postgraduate student
of the Department of Pharmacology, Faculty of Medicine,
UKM [8]. The protocol of the study was as follows.
2.1. Experimental Animals. Twenty-four healthy adult male
Sprague-Dawley rats (200–280 g) were obtained from the
institutional animal resource unit. The rats were reared in
stainless steel cages with a room temperature of 27 ±2C
with 12 hours light and dark cycle. All rats were allowed
to access food and tap water ad libitum. All the animals
handling procedures were in accordance with the institu-
tional animal ethical guideline with the ethical approval
number UKMAEC: FP/FAR/2008/Kamsiah/9-Apr/220-Apr-
2008-Feb-2011.
2.2. Source and Preparation of Diets. Commercial palm oil
(Lam Soon Edible Oil, Malaysia) was used as fresh, five times
heated and ten times heated as described by Owu et al. [9].
Briefly, the 2.5L of the oil was used to fry 1 kg of sweet
potatoes in a stainless-steel wok at 180Cfor10minutes.To
prepare five times and ten times heated oil, the hot oil was
allowed five hour cooling interval, and the entire frying pro-
cess is then repeated four and nine more times, respectively,
with a fresh batch of sweet potatoes. No fresh oil was added
between batches to replace any loss due to evaporation and
absorption of oil. The test diets were formulated by mixing
15% weight/weight of the respective prepared oils with
ground standard rat chow (Gold Coin Sdn Bhd, Malaysia),
reformed into pellets, and then dried in an oven overnight
at 70C. The preparation of test diet was in accordance with
the experimental protocol of Adam et al. [10]. However,
cholesterol was not added in the present study.
2.3. Study Design. This study was a randomized control
study.Theratswereacclimatisedforoneweekpriortofeed
the test diets. They were randomly divided into 4 groups
of six based on the diet, namely, basal diet feeding group
(C), basal diet fortified with 15% weight/weight fresh palm
oil (FPO), 5 times heated palm oil (5HPO), and 10 times
heated palm oil (10HPO) feeding groups. After 6 months of
feeding with the respective diets, all the rats were sacrificed
using diethyl ether. The proximal portion of the ascending
aorta and the arch of aorta were taken for light and electron
microscopic studies.
2.4. Sample Preparation. Each aortic sample was sectioned
into 3 segments of less than 1.0 mm thickness. They were
initially immersed for 12–16 hours at 4C in glutaraldehyde
fixative. The samples were then washed 3 times in 0.1M
phosphate buer, bulk stained with 1% buered osmium
tetroxide for 1-2 hours, and washed in distilled water for 3
times. They were then treated with uranyl acetate for 30 min-
utes, dehydrated in an ascending series of ethanol solution,
infiltrated in propylene oxide, and finally embedded in resin
at 60C for 24 hours. After the resin had polymerized, the
samples were sectioned with glass knives.
2.5. Histomorphometric Study. Semithin sections of 1 µm
thickness with 1% toluidine blue staining were viewed using
a computerized image analyzer of 100 times magnification
with the software Image-Pro Plus (Version 5.0.2.9, Media
Cybernetics, Inc., Bethesda, USA) together with light micro-
scope (Eclipse 80i, Nikon Corporation, Tokyo, Japan). The
aortic section was nominally divided into 4 quarters, and the
tunica intima and tunica media thickness were measured at
5dierent random areas for each quarter. The mean of the
20 readings was then taken as a representative of a particular
treatment group and used for statistical analysis. Thickened
tunica intima in the sample was selected for qualitative
electron microscopic study.
2.6. Qualitative Electron Microscopic Study. The resin blocks
were further trimmed at the areas of interest (thickened
tunica intima) to identify the ultrastructural changes. Ultra-
thin sections of 80 nm thickness were then collected and
stained with 3% uranyl acetate and Reynold’s lead citrate.
These specimens were examined with a transmission electron
microscope (Philips HMG 400, Philips, Eindhoven, The
Netherlands) for the presence of vacuoles and mononuclear
cells in the tunica intima. Micrographs were then taken for
qualitative description.
2.7. Statistical Analysis. The data was presented as the mean
±standard error of mean (SEM). Normally distributed data
were analysed using parametric tests analysis of variance
(ANOVA) test. Data that were not normally distributed were
analysed using nonparametric tests, Mann-Whitney Utest.
Results were considered significant if the Pvalue is <0.05.
All mentioned statistical analyses were conducted using
Statistical Product and Service Solutions (SPSS) software,
version 13.
3. Results
3.1. Quantitative Analysis. The quantitative data were shown
in Tabl e 1 . The analysis of all the measurements was done by
comparing between the frequencies of heating.
3.1.1. Tunica Intimal (TI) Thickness. In general, there was a
significant dierence in the TI thickness among all groups
(P=0.013). However, in terms of types of diets used, there
was no significant dierence of TI thickness among control
and the fresh oil groups (P=0.065).
Evidence-Based Complementary and Alternative Medicine 3
Tab le 1: Quantitative analysis of changes in the aortic wall of rats fed with dierent frequencies of heated palm oil.
Groups Tunica intima (TI) thickness (µm) ±SEM Tunica media (TM) thickness (µm) ±SEM TI : TM ±SEM
Control (C) 23.9200 ±1.6405 442.5800 ±18.7733 0.0546 ±0.0040
Fresh (FPO) 21.6250 ±1.4244 380.2100 ±11.9707 0.0570 ±0.0029b
5 times heated (5HPO) 26.7817 ±1.7856a450.7383 ±43.6100 0.0659 ±0.0048b
10 times heated (10HPO) 30.1883 ±2.1573a423.2150 ±14.8780 0.0673 ±0.0059b
aSignificant dierence between heated oil and fresh oil (P<0.05).
bSignificant dierence between control and palm oil feeding groups (P<0.05).
Results shown as mean ±standard error of mean (SEM).
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
C
b
bb
FPO 5HPO 10HPO
Tunica intima to media ratio
Figure 1: Tunica intima to tunica media ratio (IMR) in the aortic
wall of the rats fed with dierent frequencies of heated palm
oil. bSignificant dierence between control and palm oil fed groups
(P<0.05).
Comparison among groups of rats fed with palm oil with
dierent frequency of heating (fresh (FPO), 5-times (5HPO)
and 10-times heated (10HPO)) was done. Results show that
there was a significant dierence of TI thickness in the palm
oil group (P=0.012), whereby the 10-times heated group
has the thickest TI, followed by 5-times heated and lastly,
fresh palm oil.
3.1.2. Tunica Media (TM) Thickness. There was no signifi-
cant dierence of TM thickness between control and fresh
oil feeding groups as well as among the frequencies of heating
and fresh oil feeding groups (P>0.05).
3.1.3. Tunica Intima to Tunica Media Ratio (IMR). The
analysis of IMR was done by comparing between the
frequencies of heating and fresh oil. In general, there was
a significant dierence in the IMR among all groups (P=
0.009). In terms of types of diets, there was also a significant
dierence in IMR between the control and palm oil groups
(P=0.019).
Comparison among groups of rats fed with fresh (FPO)
and repeatedly heated palm oil (5HPO and 10HPO) showed
no significant dierence of IMR (P=0.281). However, the
IMR among the palm oil groups showed an increasing trend
(Figure 1).
3.2. Qualitative Analysis. For qualitative descriptive analysis,
the changes in the ultrastructure of aortae of the rats (n=
7) were examined using transmission electron microscope.
Only one sample from each treatment group which showed
the greatest IMR was chosen. The electron micrographs
(EM) of the respective groups, as well as their descriptions,
are as in Figure 2. The ultrastructure of the aorta of control
rat was shown in EM 1 (Figure 2(a)).
The endothelium of the majority of the test diet feeding
groups consists of an intact layer of endothelial cells,
maintaining their squamous characteristic. In FPO group
as shown in EM 1 (Figure 2(b)), the denuded endothelial
cells (dEC), with no mononuclear cells (MNC), were found
in the TI. The internal elastic lamina (IEL) appeared
intact, continuous, and regular and appeared to be normal
thickness. The TM consisted mainly of smooth muscle cells
(SMC), some of which appeared to be fragmented. No
intracellular vacuoles (V) were seen. In 5HPO group as
shown in EM 1 (Figure 2(c)), the intact endothelial cell
(EC) layer was found as in the FPO. However, there was a
thickening with MNC and granular material (GM) in the
subendothelial layer. The lipid accumulation and collagenous
connective tissue might be the content of GM. There was
a gap found in the IEL with migratory features of SMC
cytoplasm into the TI was also revealed. The fragmented
SMC (fSMC) was found in the TM. However, no intracellular
vacuoles were seen. In 10HPO group, the TI appeared to be
prominently thickened secondary to the plaque formation.
Theplaquewascharacterizedbyacentralnecroticcore(NC)
with surrounding MNC, myointimal cells (MIC), vacuoles
(V), and foam cells (FC) embedded in the granular material
and collagenous connective tissue. The lesion projected
prominently into the vessel lumen and it was covered by
an intact EC layer. The plaque was rested on the IEL
which appeared to be intact, continuous, and regular (EM 1
(Figure 2(d)). However, the discontinuous and irregular IEL
was found in the other area of the specimen. The fragmented
SMC was noted in the TM. The massive lipid accumulation
(LP) was also found in the subendothelial layer (EM 1
(Figure 2(e)).
4. Discussion
Consumption of saturated fat generally attributes to cardio-
vascular ailments. Palm oil which is rich in monounsaturated
fatty acids is derived from the tropical plant Elaeis guineensis
[1]. Although it is generally regarded as saturated oil, we
must also take into account its antioxidant properties. It
contains vitamin E, tocopherols, and tocotrienols which act
as potent antioxidants [2]. It helps to protect against lipid
peroxidation by trapping free radicals [11]. It has also been
4 Evidence-Based Complementary and Alternative Medicine
MNC
MNC
IEL
TM
SMC V
TI EC
L
(a)
L
TM
TI IEL
SMC
dEC
(b)
L
MNC
SMC
TM
IEL
EC TI
fSMC
(c)
L
TI
V
FC
EC
IEL
NC
TM
SMC
MIC
MNC
(d)
V
V
L
TI
LP
EC
IEL
SMC
TM fSMC
EC
(e)
Figure 2: EM 1: Ultrastructure of the aortic wall of rats fed with dierent frequencies of heated oil (3200x magnification). (a) Control, (b)
fresh palm oil (FPO), (c) 5 times heated palm oil (5HPO), and ((d) and (e)) 10 times heated palm oil (10HPO). Tunica intima (TI); tunica
medica (TM); vessel lumen (L); denuded endothelial cells (dEC); mononuclear cells (MNC); internal elastic lamina (IEL); smooth muscle
cells (SMC); endothelial cell (EC); granular material (GM); fragmented SMC (fSMC); central necrotic core (NC); myointimal cells (MIC);
vacuoles (V); foam cells (FC); disrupted IEL (arrows); lipid accumulation (LP).
proved that the tocotrienol-rich fraction (TRF) in palm oil is
known to exhibit cardioprotective eects [12]. Furthermore,
the palm oil derived vitamin E possesses the serum lipid
lowering properties mainly on cholesterol and low density
lipoprotein (LDL) [13].
However, as the antioxidants (vitamin E) are extremely
sensitive to heat, the repeated heating reduces the antioxi-
dant properties of oil [3]. Repeated thermal exposure may
generate more free radicals in the oil due to the underlying
oxidative process [14]. These free radicals are highly reactive
to bind with the lipids, proteins, carbohydrates, and DNA in
the body system, enhancing oxidative stress [5]. Therefore,
consumption of repeatedly heated oil might aggravate the
lipid peroxidation, leading to damage the arterial wall
and increase uptake of lipid, and, subsequently, develop
atherosclerosis [10]. Therefore, the heated oil feeding rats
in the present study showed obvious changes in the aortic
wall as the oil lost its protective antioxidant properties. The
gradually increased TI thickness in the heated oil treated
groups indicated that the antioxidant eect of palm oil
was gradually lost when reheating frequency was increased.
The histomorphometric and morphological findings in our
study complimented the fact that heating destroyed the
tocotrienols and other heat labile vitamins in the oil,
resulting in reduction of antioxidant properties of the oil [3].
As polyunsaturated fatty acid residues in lipoprotein
are vulnerable to free radical oxidation, the oxidized LDLs
are atherogenic via its cytotoxic eect towards arterial
endothelial cells [15]. The oxidatively modified LDLs were
found in the human and rabbit atherosclerosis lesion [16].
The modified LDLs induced the transmigration of monocyte
into the subendothelial space and it was prevented by
pretreatment with antioxidant vitamin E [17]. Moreover,
atherosclerotic changes develop when the LDLs infiltrate
into the tunica intima and accumulate in macrophages [18].
This event initiates the proliferation of intimal fibroblasts
and myointimal cells together with collagen deposition,
producing a plaque which causes the intima thickening
that is identified as the earliest indicator of atherosclerotic
process [19]. The tunica intima thickening in the control
group of the present study could be explained by the eect
of aging because the duration of study was the total of 6
months. It has been proved that aging is a responsible factor
for the dierential changes in the TI and TM thickness
[20]. However, the intimal thickening in the heated oil
treated groups might be the adverse consequence of oil
consumption, eventually leading to atherosclerosis.
Furthermore, the increase in IMR indicated the increase
in subendothelial ground material accumulation. The slight
elevation of IMR in the FPO group was probably due
to the fatty acids in nature of the oil although fresh oil
possesses antioxidant properties. However, the qualitative
results showed no obvious changes in FPO group. The palm
oildecreasestheserumtriglyceride(TG)andcholesterollevel
[21]. It also increases the level of high density lipoprotein
(HDL) [22,23]. It is well documented that high HDL level
may lower the risk of cardiovascular problem [24]. The
ultrastructural finding in FPO group of our study implicated
Evidence-Based Complementary and Alternative Medicine 5
the protective role of FPO due to its antioxidant vitamin
compositions.
Several studies have been done on consumption of
repeatedly heated oil and the impact on cardiovascular
diseases. Although one study found the temporary increase
in serum TG and LDL level in 5HPO feeding ovariectomised
rats, the morphological results showed no obvious changes
under light microscopic study [25]. In another study, the
ovariectomised rats were fed with cholesterol diet fortified
with heated palm oil and they found that the atherosclerotic
changes were revealing at the ultrastructural level without
significant alteration in the plasma lipid profile [26]. The
present study was conducted on the male rats feeding with
basal diet without being fortified with cholesterol, yet the
ultrastructural level study also revealed the similar finding as
in the study done by Adam et al. [26]. This can be concluded
as the male rats are more liable to develop cardiovascular
diseases.
Several other studies were conducted on the consequence
of atherosclerosis which attributes to the aetiology of
hypertension and cardiac problem. The study found that
the consumption of repeatedly heated oil resulted in high
blood pressure [27]. The authors also pointed out that the
free radicals generated by repeated heating might impair the
nitric oxide bioavailability on the blood vessel wall leading
to hypertension [27]. The evidence of atherosclerotic plaque
formation in the present study might also contribute the
development of hypertension. The necrosis in cardiac tissue
was found in repeatedly heated palm oil fed rats [8]. It might
be due to atherosclerosis plague formation in the coronary
artery, leading to narrowing of the lumen which diameter is
much narrower than that of the aorta. The above findings
indicated the harmful eect of consumption of reheated
oil.
In conclusion, the antioxidant property of oil is reduced
by repeated heating that increases the lipid peroxidation
which aggravates the development of atherosclerosis. There-
fore, it is important that we should utilize protective
nutritional value of palm oil in full and discourage the usage
of repeated heating oil in our daily diet to reduce the risk of
atherosclerosis.
4.1. Limitations and Recommendations. Firstly, the develop-
ment of atherosclerosis in animal models may be dierent
from human, despite the obvious histological similarities
of atherosclerosis between both species. Therefore, it is
recommended to develop the relevant model to conduct the
extended study.
Secondly, as the selected area of the aortic sample was
examined under electron microscope, the certain parts of
the aortic sample which would have more relevance to our
study might have been missed. In our humble opinion,
further detailed and quantitative studies are recommended
to explore the exact nature of disease development.
In addition, it would be interesting to investigate the
relationship between biochemical parameters and the his-
tomorphometric as well as electron microscopic study in
one single research. The future research should be aimed to
determine the safe threshold of heating frequency by using
the lower frequencies of heating such as one or two times and
so on.
Conflict of Interests
The authors declare that they have no conflict of interests.
Acknowledgments
High appreciation goes to the Universiti Kebangsaan
Malaysia Research committee, the stafrom the electron
microscopy unit of the Pathology Department and Institute
of Medical Research, Malaysia, and the staof Anatomy
Department, UKM for the technical support. The authors are
also grateful to the statistician and the postgraduate student
[8] from the Pharmacology Department, UKM, for kindly
providing the samples.
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... Studies have also shown that heating edible fats at high temperatures and feeding these to animals increase the development of atherosclerotic lesions [8,[12][13][14]. Several observations suggest that a diet rich in oxidized fat can lead to atherosclerosis [2] and ultimately cardiovascular disease [3]. The edible oils and fats constitute our daily diet and as such stands the risk of consuming oxidized fat. ...
... In a like manner, we substitute equation ( Rd is the radiation parameter, 2 Rd is the metabolic heat parameter, 3 Rd is the chemical reaction parameter. ...
... Heat transfer to blood vessels. Journal of biomechanical engineering, 102 (2), 110-118. ...
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In this article, we proposed some mathematical models to investigate the treatment effect of low density lipoprotein-Concentration and atherosclerotic blood flow in a porous micro-channel with metabolic heat and magnetic field. The heat contribution was through the hydrolysis of adenosine which aid blood circulation, and the lipid concentration was as a result of the excessive intake of Tran's fat and other saturated fats. Blood is assumed to be a mixture of formed elements and lipid, which exhibits Newtonian and incompressible characteristics, flow through a permeable solid matrix. The geometric of an atherosclerosis was formulated by incorporating the growth rate of cholesterol and treatment through the drug intake to prevent the liver from producing excessive cholesterol in the bloodstream. Following the aforementioned considerations, the proposed coupled partial differential equations were scaled using the dimensionless parameters and the resulting dimensionless equations are reduced to a system of ODE using perturbation methods involving the periodic terms due to the systolic behavior of the heart. The perturbed nonlinear ordinary differential equations were solved directly using the method of undetermined coefficient, where the blood velocity, LDL-C concentration and temperature profiles was obtained. An analytical solution for flow rate, rate of heat transfer, Sherwood number, and shear stress were also obtained respectively. Numerical computation was carried out with the aid of Mathematica, and simulation was done for flow profiles by varying the governing parameters. Graphical results are presented, showing the effect of each simulated parameters such as radiation parameter, Schmidt number, Prandtl number, Grashof number, solutal Grashof number, the treatment parameter, Hartmann number, the oscillatory frequency parameter, the pulse rate, Soret number, permeability parameter, and the height of stenosis appearing on each result. It is observed from the numerical computation that the pertinent parameters values influenced the flow profiles which clearly depicts that the investigation is of immense importance for clinicians and scientists studying cardiovascular system and pathology.
... Early comparative study from human experimentation by Tholstrup et al. 49 depicts that palm olein relatively increased plasma TC and LDL-C level p 0.0001 as compared to olive oil 49 . Also, in subsequent year, Xian et al. 50 conducted a research on the effect of reheated palm oil consumption as a risk factor for arteriosclerosis. They concluded using of repeatedly heated palm oil is becoming a predisposing factor of arthrosclerosis and leading to cardiovascular disease 50 . ...
... In Ethiopia, road side fast foods such as chips become a common trend in great Addis and other regional cities. Fast food processers use palm oil for frying purpose and they use the oil again and again, under such condition the oil chemistry will be changed and it becomes problematic for health. Repeatedly heated palm oil is also indicated as a risk factor for arteriosclerosis and leading to cardiovascular disease by Xian et al. 50 . So that, further investigation of the health effect of repeatedly heated palm oil is recommended, in addition selecting appropriate oil type for a specific type of processing is necessary. ...
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Palm oil is the world’s most commonly used vegetable oil and extracted both from fruit and seed of palm tree. However, its high saturated fatty acid content raised controversies over consumption of the oil. Few scientific findings suggest it as a risk factor for cardiovascular disease and increased consumer’s awareness over healthy diet raised claim over it. So that, this article aimed to review literatures on palm oil extraction process and its positive and negative health consequences and besides suggest strategies for healthy diet. Literature search of relevant articles was conducted by using Google scholar, PubMed, Web of science, MEDLINE, World Health Organization library online catalogue, UNICEF library, Open access thesis and dissertations published between 2009 and 2021 explored. Study reports recommend that palmitic acid from vegetable source has less effect on blood total cholesterol and low density lipoprotein cholesterol level as compared to palmitic acid from animal source. In contrary tocotrienols of palm oil lowers blood bad cholesterol level by 7-38%. Moreover, palm oil triglyceride arrangement does not have a cardiovascular risk and evidences from available in vitro and in vivo studies are not sufficient enough to conclude palm oil as a causative agent for cardiovascular disease. For healthy diet consumers should avoid trans fatty acids, solid and semi solid oils. Finally, further studies recommended on mitigation strategies to minimize process induced toxicants of palm oil to acceptable level. graphical abstract Fullsize Image
... Commercially purchased palm oil local used was five-times-heated, according to the modified method as described by Owu et al. [7][8][9]. Briefly, 2.5 L of palm oil was heated in a metal wok at 150 °C for 10 min. To prepare five-times-heated oil, the whole heating process was repeated four more times with a fresh batch and five hours cooling interval. ...
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Objective: Poor control of hypercholesterolemia which mediated by overproduction of reactive oxygen species and endothelial dysfunction leads to atherosclerosis. The present study aimed to investigate the antihypercholesterolemic and anti-atherogenic effects of Adansonia digitata (AD) in heated palm oil/cholesterol supplemented with egg yolk in rat. Methods: Quantitative phytochemical screening of aqueous extract of A. digitata was carried out to identify the phytoconstituents. In vitro and in vivo antioxidant potential was evaluated. The antihypercholesterolemic and anti-atherosclerosis activity of A. digitata was evaluated by inducing hypercholesterolemia in rats with heated palm oil/cholesterol diet supplemented with egg yolk for 10 w. At the end of the induction period, animals were divided into 5 groups of 8 rats each after 6 w of induction: Group I (normocholesterolemic rat, NCR), Group II (hypercholesterolemia rat, HCR), Group III (Atorvastatin 2 mg/kg), Groups IV (AD. 100 mg/kg) and V (AD. 200 mg/kg). Hemodynamic parameters, lipid profile, atherogenic indices and oxidative stress markers were evaluated. Results: Adansonia digitata significantly reduced the systolic arterial blood pressure (SBP), diastolic arterial blood pressure (DBP), pulsatile pressure (PP) and heart rate compared to the hypercholesterolemic group. Plant extract reveal important flavonoids and phenolic contents and has significant in vivo antioxidant efficacy. The higher dose (200 mg/kg) of the extract significantly reduced in the level of total cholesterol by 27.29 %, triglycerides by 27.60 % and the LDL-c by 36.04 % meanwhile the HDL-c increased by 277.47 % when compared to 5HPOC treated group. Atorvastatin (2 mg/kg) administered in addition to 5HPOC significantly improved in lipid profile as compared to untreated rats. Furthermore, the histopathological examination of aorta of 5HPOC-treated rats indicated that the aqueous extract of A. digitata significantly attenuated atherosclerosis lesions. Conclusion: The aqueous extract of A. digitata possessed antihypercholesterolemic and anti-atherogenic effects via modulation overproduction of reactive oxygen species and endothelial dysfunction.
... 2 ...
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Atherosclerosis is a form of cardiovascular illness characterized by an accumulation of insoluble substances, cellular debris and inflammation in the innermost layer of the arterial wall. Statin drugs have been the primary method for treating atherosclerotic lesions, but recent research suggests that lifestyle changes, in particular consuming a diet rich in antioxidants, may be equally effective at preventing and potentially reversing the process of atherogenesis. In this research, we formulated mathematical models to study the effect of the antioxidants on the legion regression of an atherosclerosis at the biological, and the geometry of the irregularity caused by an oxidation shown as the first equation. The second equation is the momentum equation, which is the fluid flow equation, the third equation is the energy equation and finally, the fourth equation is the mass diffusion of cholesterol equation. The aforementioned equations were scaled and reduced to a system of an ordinary differential equation. The biological model led to analytical solutions of the velocity, concentration and temperature profiles. Mathematica codes were developed to simulate the effect of the governing parameters on the flow profiles. Through the use of these equations, applied mathematicians can supply cardiologists with means for simulating and numerically analyzing various lesion regression scenarios.
... (Rohr-Udilova et al., 2008) stated that; prolong ingestion of heated palm oil mice must saw to origin alterations in kidney tissue. According to Xian et al (2012). Some study recommends that use of frequently recooked cause plaque in the blood arteries of different organ. ...
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To probes out the oxidative effects of (palm oil) on electrolytes and histo-logical alteration in mice kidney. Twenty four albino mice were distributed into three (I to III) groups consist 8 mice in every group. (Group I) was fed with common food, (FPO) (groups II) and oxidized palm oil (10HPO), (group III) were feed for a 4 weeks. Results revealed that, Group II (55.5 ± 4.04 g) and III (68.11± 9.97 g) mice gain significant (p < 0.05) body weight. Creatinine retention was prominently more noteworthy (p<0.05) in oxidized Group III(138.54±2.50mg/dl) Urea concentration levels were measured in control (Group I) of mice existed (5.6±0.55 mg/dl) and in original palm oil (Group II) remained (4.0±0.52 mg/dl) whereas in thermo-chemically palm oil (Group III) were (4.80±.50 mg/dl) Serum centralism of potassium ions in fresh palm oil Group II (6.05±0.15mmol/L) was basically (p<0.05) higher then control Group I (5. 77±0.36 mmol/L) and thermally oxidized Group III (5.77±0.18 mmol/L) Concentration of Sodium ions in control (Group I) were (135.67±067 mmol/L) and in fresh palm (Group II), were (130.17±1.26 mmol/L) however in thermally oxidized (Group III) were (140.17±1.67 mmol/L). noticeably ((p<0.05) greater in thermally oxidized (Group III) Histologically, group II confirmed vacuoles in the medullar region, while group III checked cell in the medullary portion that see swelling with varying tubules contain esinophilic content in the lumen. It is established that oxidized palm oil has impact on organ and should be avoided
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Palm oil (PO), although subject of controversies, is the most consumed oil and the first source of oil widely produced. In this review, we discussed its biochemical composition in fatty acids, carotenoids, vitamin E, its phenolic compounds, and its nutritional benefits. We addressed its biochemical properties in relation with the stereospecific distribution of its unsaturated fatty acids at the sn-2 position in triacylglycerols. PO is one of the most stable oils, which help it prolong food storability mostly due not only to its content of saturated fatty acids, but also to its antioxidant compounds. PO plays an important role in the prevention of many pathologies (diabetes, cardiovascular diseases, obesity and cancers). It is widely use in nutrition especially in the food industry and in biodiesel industry. Faced with attacks from environmentalists who blame PO for destorying biodiversity, there is an urgent need to develop a sustainable PO production plan. Compliance with sustainable PO goals would help ease those controversies. The use and consumption of PO in normal or moderate amounts in a varied, balanced and adequate diet does not present any known health risk. Education campaigns on the nutritional benefits of PO should be promoted.
Chapter
Recycling cooking oils in daily life is a common thing to do for some people to reduce the costs. However, this habit will lead to an unhealthy lifestyle. Reheating oil undergoes a series of chemical changes such as oxidation and hydrolysis, which will produce some harmful substances that will generate lipid peroxidation that could possibly be dangerous to human health. This experiment is conducted on how to detect the turbidity of the oil by using a simple experimental setup.
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Recurrent using of oils during frying of food is a common trend in houses and commercial sectors. The repeated heated oil which is thermally oxidized may have detrimental effects on biological tissues. This study was conducted to examine the effect of repeated fried palm oil alone or in combination with ginger on serum lipid proåle, total antioxidant activity (AOA), semen picture and p53 gene expression in rat tissues. Twenty four male rats were divided into four groups (6 each); control (normal basal diet), FPO (diet+ 15% fresh palm oil), RFO (dietmixed with 15% repeated fried palm oil), RFO+ G (diet + RFO+ ginger 1%). The results showed that the high fat diet (FPO or RFO) cause signiåcant elevation in total cholesterol, phospholipids, HDL-c and LDL-c. AOA increased in hepatic tissue but decreased in testicular tissue of rats consumed RFO indicating oxidative stress which seems to affect semen picture dramatically causing a decrease in sperm count, motility% and live-dead% with an increase in sperm abnormalities %. Moreover, P53 gene expression increased signiåcantly in both liver and testis of rats fed RFO. Ginger succeeded to modulate this effect on p53 expression but failed to modulate the biochemical alterations. It could be concluded that using repeated fried oil have obvious harmful effect for vital tissues like liver and reproductive system but the protective role of ginger need further studies.
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The goal of this study was to determine the possible mechanism that is involved in the blood pressure-raising effect of heated vegetable oils. Adult male Sprague-Dawley rats were divided into 11 groups; the control group was fed with rat chow, and the other groups were fed with chow that was mixed with 15% weight/weight palm or soy oils, which were either in a fresh form or heated once, twice, five, or ten times. Blood pressures were measured at the baseline and throughout the 24-week study. Plasma nitric oxide levels were assessed prior to treatment and at the end of the study. Following 24 weeks, the rats were sacrificed to investigate their vascular reactivity using the thoracic aorta. Palm and soy oils had no detrimental effects on blood pressure, and they significantly elevated the nitric oxide contents and reduced the contractile responses to phenylephrine. However, trials using palm and soy oils that were repeatedly heated showed an increase in blood pressure, enhanced phenylephrine-induced contractions, reduced acetylcholine- and sodium nitroprusside-induced relaxations relative to the control and rats that were fed fresh vegetable oils. The blood pressure-raising effect of the heated vegetable cooking oils is associated with increased vascular reactivity and a reduction in nitric oxide levels. The chronic consumption of heated vegetable oils leads to disturbances in endogenous vascular regulatory substances, such as nitric oxide. The thermal oxidation of the cooking oils promotes the generation of free radicals and may play an important contributory role in the pathogenesis of hypertension in rats.
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Palm oil is considered as plant oil in which two types of cooking oil, palm seed oil and palm oil are derived. Palm oil has almost 50% saturated fatty acid and 50% poly unsaturated fatty acid. It is considered to be useful due to metabolites products such as prostacycline and antithrombois in cardiovascular disease (C.V.D) and variation in lipoprotein. In the present study we examined the effect of 12% palm oil on 30 days old male rats (149.3±10.7 g) for 60 days. The changes of weight and food intake were recorded. The result showed that the mean value of rats weight was increased with energy intake in diet (p< 0.05). The serum levels of cholesterol, and HDL-C were increased significantly (p< 0.05), while the levels of triglyceride and LDL-C were decreased but statistically not significant. In conclusion, using palm oil can be useful for prevent of cardiovascular disease.
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A number of tissue enzymes are valuable tools as diagnostic agents. LDH, AST, ALT and GGT, in addition to cholesterol and triglyceride are demonstrated to be constituents of some tissues (liver, heart, kidney, adipose tissue, and aorta, adipose and skeletal muscles etc.). Any damage to these tissues as a result of lipid accumulation or fatty infiltration could result in a significant increase in serum values becoming a valuable diagnostic tool for cardiovascular disease. In the present study, effects of palm oil and soybean oil (both at 5% level) on serum lipid and some serum enzymes were examined for six weeks. At the end of the 6th week, serum cholesterol and triglycerides were significantly reduced (p<0.05) in palm oil fed rats compared to soybean oil fed rats. It is thus considered that palm oil consumption could better prevent against coronary heart disease risk than soybean oil.
Ju Chen – University of California, San Diego, Department of Medicine, La Jolla, CA, USA Robert Ross – University of California, San Diego, Cardiology Section, San Diego, CA, USA
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Professor Majno is a foremost philosopher-pathologist in the company of Drs Oliver Wendell Holmes, Claude Bernard, Lewis Thomas, and Ruy Pérez-Tamayo. Dr Joris is a productive bioscientist and specialist in inflammatory and vascular phenomena, exemplified in sparkling chapters. Their book is replete with excellent original or borrowed gross and photomicrographs, 27 color plates, x-rays, scans, electron micrographs, immunohistochemical tests, and many outstanding original or adapted diagrams of cells and tissue reactions, graphs, flow charts, and tables that make splendid learning and teaching aids. Some 4500 references are provided, from the time of Hippocrates to the present, quite a few from 1995 and 1996, which takes some doing.Pathobiology examines how and why abnormalities develop, using animal and plant models, cell and tissue cultures, and biologic and biochemical experiments. Philosophers of medicine are rare and to be cherished, for most practicing pathologists have little time to dream. In Cells, Tissues, and
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Heating palm oil for l0 minutes (P()lH) caused signil-icant reduction in cr-tocopherol (a-tl). o-tocotrienol (cr-tt). y-tocotrienol (T-tt) and 6-tocotrjenol (6-tt) cornparccl to fresh palm oil (P()F-). Hcatcd l'ive tinres palnr oil (PO5lJ) also caused a lurther reduction in s-tf. o-tt, y-tt and 6-tt. Up to 98%, of thc thrcc nrost abundant vitarnin E ll.actions in thc palm oil. nanrely o-tf. cr-tt and y-tt, were destroyed by repeated heating. Similarly, heating soy oil lirr fivc tintcs (SO5ll) also signilic:antly lowcred the concentration of all three tocopherols, nanrely cr-tl-. y-tocopherol (1-tl') and b-tocopherol (5-tl). corrrparcd to licsh soy oil (SOF) and heated once soyoil (SOIH). Howcver.thclattcronlymanagcdtosignil'icantlylowcrthclcvcl ofcr-tl'withoutal'l'ectinglcvelsofy-tland6-tl'. Up to 60% oly-tf. which is the most abundant variety ol'vitamin E in soy oil, was l()st up()n heatin-e rcpeatcdly lirr llve timcs. Thc findings of this study suggest that thc extenl ol'vitantin rcductiott was rx)[ only allcctctl by thc liccpency ol'heatine but varied accordingtothedi|.I.erentvitanlinE|i.actitirrs.HeatingappcarSt0hllVenlorecI.Icct(}llct-tl...O{-tt.Y-ttandy-tl.ht|ess tt and 6-tf.
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Until recently, most envisaged atherosclerosis as a bland arterial collection of cholesterol, complicated by smooth muscle cell accumulation. According to that concept, endothelial denuding injury led to platelet aggregation and release of platelet factors which would trigger the proliferation of smooth muscle cells in the arterial intima. These cells would then elaborate an extracellular matrix that would entrap lipoproteins, forming the nidus of the atherosclerotic plaque. Beyond the vascular smooth muscle cells long recognized in atherosclerotic lesions, subsequent investigations identified immune cells and mediators at work in atheromata, implicating inflammation in this disease. Multiple independent pathways of evidence now pinpoint inflammation as a key regulatory process that links multiple risk factors for atherosclerosis and its complications with altered arterial biology. Knowledge has burgeoned regarding the operation of both innate and adaptive arms of immunity in atherogenesis, their interplay, and the balance of stimulatory and inhibitory pathways that regulate their participation in atheroma formation and complication. This revolution in our thinking about the pathophysiology of atherosclerosis has now begun to provide clinical insight and practical tools that may aid patient management. This review provides an update of the role of inflammation in atherogenesis and highlights how translation of these advances in basic science promises to change clinical practice.
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This study examined the effects of heated vegetable oils in estrogen deficient rats. Eighty female Sprague-Dawley rats were divided equally into eight groups and given treatment as follows: (I) intact (non-ovariectomised), basal diet (control group); (II) ovariectomised, basal diet; (III) ovariectomised, basal diet fortified with 15% weight/weight (w/w) fresh soya bean oil (FSO); (IV) ovariectomised, basal diet fortified with 15% weight/weight (w/w) soya bean oil heated once (1H-SO); (V) ovariectomised, basal diet fortified with 15% weight/weight (w/w) soya bean oil heated five times (5H-SO); (VI) ovariectomised, basal diet fortified with 15% weight/weight (w/w)fresh palm oil (FPO); (VII) ovariectomised, basal diet fortified with 15% weight/weight (w/w) palm oil heated once (1H-PO); (VIII) ovariectomised, basal diet fortified with 15% weight/weight (w/w) palm oil heated five times (5H-PO). Duration of treatment was 6 months. Blood was taken at baseline and monthly interval for 6 months for determination of serum lipid profiles and malondialdehyde (MDA) levels. Serum homocystein and interleukin-6 were assayed at baseline and after 6 months of study. At the end of the study the rats were killed and consistent segments of the ascending aorta were taken for histopathological examination. The specimens were sectioned transervely and stained with haematoxylin-eosin and Verhoeff van Gieson for light microscopy. Measurements of the intimal thickness and the ratio between tunica intima / tunica media were calculated using computerised image analyser. Heated and fresh palm oil cause transient changes in lipid profiles, whereas soya oil; fresh, heated once and heated five times as well as heated once palm oil caused an increase in serum LDL-cholesterol. Fresh and heated vegetable oils diet did not alter the ratio between tunica intima and tunica media, serum MDA and homocystein level. Histological study showed no obvious focal or diffuse atherosclerotic plague formation with an intact internal elastic lamina and no evidence of smooth muscle cell migration.