THE EFFECTS OF FRESH AND THERMOXIDIZED PALM OIL DIETS ON SOME HAEMATOLOGICAL INDICES IN THE RAT

86
Nigerian Journal of Physiological Sciences 19(1-2): 86 -91 © Physiological Society of Nigeria 2004


THE EFFECTS OF FRESH AND THERMOXIDIZED PALM OIL DIETS
ON SOME HAEMATOLOGICAL INDICES IN THE RAT


* O. E. MESEMBE, # I. IBANGA, and + E. E. OSIM


•
Departments of Anatomy, # Haematology and +Physiology, College of Medical Sciences
University of Calabar, Calabar, Nigeria

Summary: The effects of fresh and thermoxidized palm oil diets on some haematalogical indices in
the rat were investigated in albino rats (Wistar strain). The animals were divided into three groups
namely, the first group fed on thermoxidized palm oil (TPO) diet, a second group fed on fresh palm
oil (FPO) diet and a third fed on normal rat feed (control) only respectively for 14 weeks. Each of the
palm oil diets contained 15% (w/w) thermoxidized or fresh palm oil. The packed cell volume (PCV)
of the TPO group (44.87 + 0.8%) was significantly (P < 0.001) lower than that of the FPO group
(52.50 + 0.4%) and control group (54.75 + 1.3%). The haemoglobin (Hb) concentration of the TPO
group (11.66 + 0.8g/dl) was significantly (P < 0.001) lower than that of control group (13.14 +
0.4g/dl) and the FPO group (12.88 + 0.8g/dl). The red cell count (RBC) of the TPO group (6.06 x
106 + 0.4 x 106 per mm3 of blood) was significantly (P < 0.001) lower than that of control group (7.28
x 106 + 0.4 x 106 per mm3 of blood) and the FPO group (7.19 x 106 + 0.2 x 106 per mm3 of blood).
The white blood cell count (WBC) of the TPO group (3.42 x 103 + 0.1 x 103 per mm3 of blood) was
significantly (p< 0.001) higher than that of control group (2.39 x 103 + 0.1 x 10 per mm3 of blood)
and FPO group (2.51 x 10 3 + 0.1 x 103 per mm3 of blood). There were no significant differences
between the heamatological indices of the fresh palm oil (FPO) and control groups. Our results
suggest that chronic consumption of thermoxidized palm oil diet may result in anaemia and
leucocytosis in the rat.


Key Words: Fresh palm oil; Thermoxidized palm oil; RBC; WBC; Hb; PCV.



Introduction
Long term consumption of oxidized oils
Palm oil, derived from the fruit of
and fats has been reported to cause growth
Elaesis guineensis is the most widely used
retardation, thrombosis, fatty livers, essential
cooking oil in Nigeria. It is consumed fresh
fatty acid deficiency, nucleic acid deficiency
or thermally oxidized. It is fresh when
and micronutrient malnutrition leading to
obtained from the pulp of the palm fruits by
deactivation of key metabolic enzymes (Hill
squeezing and boiling at low temperature to
et al, 1982; Izaki et al, 1984; Golden and
remove debris. It is thermally oxidized when
Ramdath, 1987; Isong et al, 1992; Osim et al,
the fresh form is subjected to several rounds
1992). The free radicals that are generated
of heating at high temperatures.
may be involved in the etiology of diseases
Fresh palm oil has low oxidation values
such as cancer, diabetes, arthritis, and cataract
(Rossel, 1983) and is relatively stable to
formation (Sun, 1990; Pryor, 1991; Lunec,
oxidation (Gapor et al, 1989). Generally,
1992).
oils are thermally oxidized to render them
The haematological system is a major
more palatable. However, the thermoxidation
organ system. The vasculature in which
has a deteriorative effect on dietary oils
blood flows present surface area of over
(Perkins and van Akkerren, 1965; Peers and
10000m2, making this system interact
Swoboda, 1982; Isong, 1988). Also, following
extensively with other systems in the body
ingestion of thermally oxidized oil, there is a
(Mackie et al, 1999). And changes in
concomitant evolution of very cytotoxic and
haematological parameters may occur as a
destructive by products (Plea, 1975; Frankel,
consequence of other systemic diseases
1980; Ziomski, 1982) which are injurious to
(Mackie et al, 1999). There is therefore a
cells tissues and organs (O’sara et al, 1969;
possibility that thermoxidized palm oil diet
Tappel 1973; Gabriel et al, 1979; Meredith,
will adversely affect the hematological
1984).
system. This study examines this possibility.

---

87
O. E. Mesembe et al

At the end of the feeding protocol, the

Materials and Methods
rats were anaesthetized with chloroform after
20 litres of fresh palm oil was purchased from
over night fast. Blood was collected into
Akim market in Calabar, Nigeria. The oil was
heparinized screw cap bottles for
divided into two equal portions. One portion
determination of haemoglobin, red blood cell
was thermally oxidized as described by Isong
count, haematocrit and white blood cell count.
(1988) and Osim et al (1992); whereas the
Haemacocrit (PCV) was estimated using
other portion was used in its fresh form since
microhaematocrit method according to
these are the two common forms of palm oil
Alexander and Griffiths (1993a); while
used for cooking. The thermoxidied palm oil
haemoglobin (Hb) concentration was
was obtained as follows:
determined using cyanomethaemoglobin
Fresh palm oil was heated at 1500C in a
method according to Alexander and Griffiths
stainless steel pot intermittently for five times
(1993b); whereas, the red blood cell count
with each lasting twenty minutes. At the end
(RBC) and white blood cell (WBC) count
of each heating session, the oil was allowed to
were estimated by visual means using the new
cool for five hours. Since the level of palm
improved Neubauer counting chamber
oil in most West African dishes is about 15%
according to Dacie and Lewis (1991).
(Umoh, 1972), fifteen grams of the cooled

thermoxidized palm oil was mixed with
Statistical Analysis
eighty- five grams of rat feed and was
Student’s t – test and analysis of variance
designated test diet I. Fifteen grams of the
were used to analyze the data. Values of P <
fresh palm oil was mixed with eighty-five
0.001 were regarded as significant.
grams of rat feed and was designated as test

diet II. The diets were stored in black
Results
containers at 40C to prevent further oxidation
The packed cell volume of thermoxidized
of the oil component.
palm oil group (44.87 + 0.8%) was
Twenty-four albino Wistar rats were bred
significantly (P < 0.001) lower than that of the
in the animal house of the Department of
control (54. 75 + 1.3%) and fresh palm oil
Anatomy, University of Calabar, Calabar.

group (52.50 + 0.4%). The packed cell
The animals were divided into three groups of
volume of fresh palm oil group was not
eight rats each. The rats were about the same
significantly different from the control group.
age (56 - 60 days old) and
(Fig.1).
weighed between 50-55g at the start of the

experiments.
The haemoglobin concentration of
The rats in the first group were fed on
thermoxidized palm oil group (11.66 +
thermoxidized palm oil diet (diet I). The
0.8g/dl) was significantly (P < 0.001) lower
second group was fed on fresh palm diet (diet
than that of control group (13.14 + 0.4g/dl)
II); while the third group served as the control
and fresh palm oil group (12.88 +
group and was fed normal rat-feed. The feed
0.8g/dl).There was no significant difference
was obtained from Livestock Feeds, Nigeria
between that of the fresh palm oil group and
Limited, Lagos, Nigeria. Rats in the three
that of control (Fig.2).
groups were allowed the feed and water ad
libitum for fourteen weeks.

Fig. 1: Packed cell volume in rats fed thermozidized

palm oil, fresh palm oil and control diets

60

XXX
50

)
xxx
%

40


30


20

Packed cell volume (

10


0
Thermoxidized Fresh pal
m oil Control diet
palm oil diet
diet


Result presented as mean + SEM; n = 8
XXX = P < 0.001 significant in comparison
with control and fresh palm oil groups

---

Palm oil diets and haematological indices
88

Fig. (2) Haemoglobin concentration in rats fed
thermoxidized palm oil, fresh palm oil and control
diets
16
XXX
14
xxx
12
10
8
6
4
2
Haemoglobin concentration (g/dl)
0
T herm ox idized palm
F resh palm oil diet
C ontrol diet
oil diet
Result presented as mean + SEM; n = 8
XXX = P < 0.001 significant in
comparison with control and fresh palm
il



Fig. 3 Red blood cell count in rats fed thermoxidized palm oil,
fresh palm oil and control diets

9

xxx
8

XXX
)

3 7
m


6
x106 m


5

4


3


ed blood cell count (N 2
R

1

0


Thermoxidized palm
Fresh palm oil diet
Control diet
oil diet


Result presented as mean + SEM; n = 8

XXX = P < 0.001 significant in comparison with

control and fresh palm oil groups


The red cell count of thermoxidized palm oil
(3.42 x 103 + 0.1 x 103 cells per mm3 of blood) was
group (6.06 x 106 + 0.4 x 106 cells per mm3 of
significantly (P < 0.001) higher than that of control
blood) was significantly (P < 0.001) lower than
(2.39 x 103 + 0.1 x 103 cells per mm3 of blood) and
that of control group (7.28 x 106 + 0.4 x 106 cells
fresh palm oil group (2.51 x 103 + 0.1 x 103 cells
per mm3 of blood) and fresh palm oil group (7.19 x
per mm3 of blood). The difference between values
106 + 0.2 x 106 cells per mm3 of blood). There was
of fresh palm oil group and control rats not
no significant difference between that of the fresh
significant (Fig.4).
oil group and that of control (Fig.3). The white

blood cell count of thermoxidized palm oil group

---

89
O. E. Mesembe et al

F ig . 4 W h ite b lo od c e ll c o u nt in ra ts fe d th e rm ox id iz e d
p a lm o il, fre s h p a lm o il a nd c on tro l d ie ts
4
R e s u lt p re s e n te d a s m e a n + S E M ; n = 8
xxx
3 .5
)
3
3
mm
X X X
3
2 .5
(N x 10
2
l
count
1 .5
ood cel
t
e
bl
1
Whi
0 .5
0
T h e rm o x id iz e d p a lm o il
F re s h p a lm o il d ie t
C o n tro l d ie t
d ie t
X X X = P < 0 .0 0 1 s ig n ific a n t in c o m p a ris o n w ith
c o n tro l a n d fre s h p a lm o il g ro u p s
Discussion
concentration. It represents the percentage of
In this study, the chronic consumption
RBC in blood (Kiraly, 1980). Therefore the
of thermoxidized palm oil diets by rats has
decrease in PCV observed in this study is in
been observed to cause alterations in
agreement with the observed decrease in RBC
haematocrit (PCV), haemoglomin (Hb), red
counts.
blood cell (RBC) count and white blood cell
The Hb concentration was significantly
(WBC) count.
lower in the rats fed on thermoxidized palm
These results showed that the RBC count was
oil diet when compared to rats fed on fresh
significantly lower in the rats fed
palm oil and control diets. This decrease in
thermoxidized palm oil diet when compared
Hb concentration may be a consequence of
to the fresh palm oil and control groups. This
reduced uptake of iron by the damaged
decrease may be due to the suppressive effect
intestinal mucosa resulting in a reduced
of the hazardous constituents of thermally
bioavailability of iron in the system. This is
oxidized palm oil on the bone narrow. This is
borne out by the work of Igiri et al, (1994),
supported by experiments of O’sara et al
which showed that the intestinal mucosa of
(1979); Frankel, (1980) and Meredith (1984)
rats was severely damaged by chronic
who reported that the oxygen derived free
consumption of thermoxidized palm oil diet.
radicals and dihydroxy esters contained in
The decrease in Hb concentration may also be
oxidized oils cause injury to cells, tissues and
attributed to the decreased storage of iron in
organs. These constituents may have
the liver as a result of damage to the liver.
suppressed the process of growth and
The liver stores iron as ferritin and
differentiation in the marrow.
haemosiderin (Finlayson et al (1999). In
Failure of erythropoietin production may
agreement, Osim et al (1994) have shown that
have also caused the decrease in RBC count
congestion of hepatic sinusoids and
in the group fed the test diet. The kidney is
degenerative changes in the hepatic lobules
the main source of erythropoietin, which is
occurs in rats chronically fed thermally
produced by interstitial peritubular cells
oxidized palm oil diet. The damage to the
(Davidson et al, 1999). Osim et al (1994)
liver may have depleted the amount of iron
demonstrated that thermoxidized palm oil diet
stores and therefore resulted in lower
causes tissue damage to the kidney-
haemoglobin concentration. Comparable low
specifically partial tubular atrophy. In fact,
packed cell volumes, red blood cell count and
patients with renal dysfunction are anaemic
haemoglobin concentration observed in rats
due to failure of erythropoietin production
fed thermoxidized palm oil diet indicate that
(Eldestein et al, 1997).
the rats were anaemic.
The PCV otherwise known as
The WBC counts was observed to
haematocrit is a function of RBC
increase in the rats fed on thermoxidized palm

---

Palm oil diets and haematological indices
90
oil diet. This is in line with normal
Hunker J. A, Boon N. A. 18th ed.

physiologic response following the
Churchill Living Stone, Edinburgh Pp
perception of an insult by the body. Osim et
417-470.
al (1994) have demonstrated that
Edelstein, C. L., Ling. H. and Schrier, R. N,
consumption of thermoxidized palm oil diets
(1997). The nature of renal cell injury
caused liver damage. It is likely therefore that
Kidney International 5: 1341-1351.
damage to the liver cells may have caused the
Finlayson, N. D. C., Hayes, P. C. and
insult that contributed to the observed
Simpson, K. J.(1999) Diseases of the
increase in WBC count. In agreement,
liver and biliary system. in: Davidson’s
Finlayson et al (1999) have reported that
principles and practice of medicine. Eds.
leucocytosis may occur in hepatic damage.
Haslet C, Chilvers E. R, Hunker J. A. A.
Although there were no significant
Boon N. A., 18th ed. Churchill Living
differences between the fresh palm oil and
Sone, Edinburgh. Pp 683-736.
control groups, there was a tendency for
Frankel, E. N. (1980). Lipid Oxidation Prog.
haematological indices in rats fed on fresh
Lipid Res. 19.1-22.
palm oil diet to be different from rats fed on
Gabriel, H. G., Alexander, J. C. and Valli, V.
control. This may be so because other forms
E. (1979). Biochemical and histological
of oxidation e.g photolytic, enzymic,
effects of feeding and thermally
hydrolytic and chemolytic may be going on in
Oxidized rapeseed oil and Lard to rats.
the fresh palm oil (Artman, 1969; Frankel,
Can J. Comp. Med. 41:98-106.
1980; Gurr and James, 1980; Lake and
Gapor, A. B., Ong, A. S. H., Kato, A.
Waltherworth, 1980). There is therefore the
Watanabe, H., Kawada, T., (1989).
need to protect fresh palm oil from various
Antioxidant activities of palm vitamin E
other sources of oxidation. Alternatively,
with special reference to tocotrienol. Int
fresh palm oil should be used as soon as it is
J Oil Palm Res Dev. 1:63-67.
prepared.
Golden, M. H. N., and Ramdath, D., (1987).
If the results are applicable in man, they
Nutritional aspects of free radicals Free
suggest that there is reason for concern
Radic Bio Med. 46:55-68.
regarding adverse haematological Gurr, A. I. and James, A. T., (1980). Lipid
consequence of chronic consumption of
Biochemistry, An introduction 3rd ed.
thermally oxidized palm oil diets. Chronic
Chapman and Hall London. Pp 219-223.
consumption of thermally oxidized palm oil
Hill, E. G., Johnson, S. B., Lawson, L. D.,
diets may be dangerous to health since it may
Manfouz, M. M., Holman, R. T. (1982).
result in anaemia and leucocytosis. Therefore
Pertubation of the metabolism of
chronic consumption of this form of treated
essential fatty acids by dietary partially
palm oil should be discouraged.
hydrogenated vegetable oil. Pro. Natl

Acad. Sci. 79: 953 – 957.
References
Igiri, A. O., Ibegbu, A. O., Osim, E. E.
Alexander, R. R. and Griffiths, J. M. (1993a).
(1994). The Morphological and
Haematocrit in: Basic Biochemical
histological changes in the small
methods, 2nd ed., John Wiley and Sons
intestines induced by Chronic
Inc. New York, Pp 186-187.
consumption of palm Journal for
Alexander, R. R. and Griffiths, J. M. (1993b).
Applied Sciences.3and 4:144-153.
Haemoglobin determination by the
Isong, E. U. (1988). Biochemical and
cyanomethaemoglobin method. In:
nutritional studies on rat of thermally
Basic Biochemical methods. 2nd ed.
oxidized palm oil (Elaesis guineensis).
John Wiley and Sons, Inc. New York.
PhD. Thesis, University of Calabar,
Pp188-189.
Nigeria.
Artman, N. R. (1969). The chemical and
Isong, E. U., Ifon, E. T., Eka, O. U. Essien, E.
biological properties of heated and
U. and Umoh, I. B. (1992). Effect of
oxidized fats Adv Lip Res 7:245-330.
intermittently thermoxidized palm oil on
Dacie, J. V., and Lewis, S. M. (1991).
normal and malnourished rats. Trop J.
Practical haematology, Churchill Living
Appld Sci 2:118-121.
Stone, Edinburgh, Pp41-57.
Izaki Y., Yoshikawa S and Uchiyama M.,
Davidson, A. M. Cumming, A. D., Swainson,
(1984). Effect of ingestion of thermally
C. P. and Turner, N. (1999). Diseases of
oxidized frying oil on peroxidative
the Kidney and Urinary systerm. In:
criteria in rats. Lipids 19(5):324 –331.
Davidson’s principles and practice of
Kiraly, D. A. (1980). Haematology problem.
Medicine. Eds. Haslet C, Chilvers E. R,
Am J. Med. Tech 80: 25-27.

---

91
O. E. Mesembe et al
Lake, B., Walterworth, M., (1980).

Perkins, E. G., and vanAkkerren, L. A.


Foods and nutrition.Mills and Boon Ltd.
(1965). Heated fats subjected to deep
London Pp10-20.
fat frying processes. J. Am. Oil Chem.
Lunec, H. (1992). Oxygen radicals, their
Soc. 42: 161 – 166.
measurement and role in major diseases.
Plea, R. M., (1975) Protein synthesis and
J I F C C 14(2): 58-63
absorption in rats fed with oxidized oil.
Mackie, M. J., Ludlam, C. A. and Haynes, A.
Practitioner 224:306-421.
P. (1999). Diseases of the blood. In:
Pryor, W. A. (1991). The antioxidant
Davidson’s principle and practice of
nutrients. What we know, what to find
medicine. Eds Haslet C, Chilvers E. R,
out. Am . J Clin. Nut.r 53:3915-3935.
Hunker J. A.A, Boon NA, 18th ed.
Rossell, J. B. (1983). Measurement of
Churchilll Livingstone, Edinburgh Pp
rancidity. In rancidily in foods. Ed,
737-800
Allen JC, Hamilton R. J. Applied
Meredith, S. (1984). Free radicals: Friend or
Sciences Publishers Ltd. England Pp.21
foe? Medicine Digest 10 (4): 23-25
– 46.
O’sara, R. W., Stewart, L, Brown, J. and
Sun, Y. (1990). Free radicals, antioxidant
Harph, W. C. (1969). Carcinogenicity
enzymes and carcinogens. Free Rad
of heated fats and fractions. J Natl
Biol Med 8:583-599.
Cancer Inst. 42: 275-278).
Tappel, A. L. (1973). Lipid peroxidation
Osim, E. E., Owu D. U., Isong, E. U. and
damage to cell components. Fed. Proc.
Umoh, I. B. (1994). Influence of
32: 1870 – 1874.
Chronic consumption of thermoxidized
Umoh, I. B. (1972). Changes in the nutritive
and fresh palm oil diets on basal
values of some Nigerian diets after
metabolic rate, body weight and
cooking by certain South eastern
Morphology of tissues in rats. Discov
traditional methods. Ph.D. Thesis,
Innov. 6:389-396.
University of Ibadan, Nigeria.
Osim, E. E., Owu, D. U., Isong, E. U. and
Ziombski, H. (1982). Chemical and
Umoh, I. B. (1992). Influence of
nutritional changes in heated fats. III.
Chronic consumption of thermoxidized
Changes in nutritive value. Raezniki
palm oil diet on platelet aggregation in
Panstwowego Zadkladu Itigiency, 33
the rat. Discov. Innov. 4:83087.
(3): 162 – 170.
Peers, K. E. and Swoboda, P. A. T. (1982).
Deterioration of sunflower seed oil
under simulated frying conditions and
Received: April 16, 2004
during small scale frying of potato
Accepted October 6, 2004
chips. J. Sci Food Agric. 33(4): 389 –
395.

---