CANOLA OIL BENEFITS AND SIDE EFFECTS

Canola oil benefits and side effects

Orignial Article

Canola oil is marketed as vegetable oil for cooking and use in salads. It is one
of the most widely consumed food oil in Canada, and has been considered as
GRAS (Generally Recognized as Safe) material by the US FDA. It contains 55%
of the monounsaturated fatty acid; oleic acid, 25% linoleic acid and 10%
alpha-linolenate [polyunsaturated fatty acid (PUFA)], and only 4% of the
saturated fatty acids (SFAs). Many health associations recommended the
dietary goals for an average diet containing about 30% of calories as fat made
up of less than 10% saturated fatty acids, and they consider canola oil having
benefits on health in general. [1]

ANTI-OXIDANT ACTIVITY

Canolol (4-vinyl-2,6-dimethoxyphenol ) is a highly potent ROO(*) scavenger,
isolated from crude canola oil (rapeseed). After roasting the seed, the canolol
content increases but it content is low in highly purified canola oil. Researcher
found its potency was much greater than that of well-known antioxidants,
including alpha-tocopherol, vitamin C, beta-carotene, rutin, and quercetin. [2]

CHOLESTEROL-LOWERING EFFECTS AND GLUCOSE TOLERANCE

Researchers found that canola oil has benefits on cholesterol. In a study, 28
human subject with mean levels of total and low density lipoprotein cholesterol
of 6.0 (1.1) mmol/L, and 4.1 (1.0)mmol/L, respectively consumed a low
saturated fat diet, which included either 30g/d nuts (nut diet) or one serving of a
cereal containing Canola oil (cereal diet). Researchers found that both diets
could lower the total cholesterol (TC) and low density lipoprotein cholesterol
(LDL-C) to a similar extent. Thus, foods with a similar fatty acid composition to
nuts can produce comparable benefits in lipoprotein mediated cardiovascular
risk. [3]

Lipid-lowering diets containing either rapeseed oil or olive oil may have benefits
on serum lipoprotein concentration and glucose tolerance in hyperlipidemic
subjects. In a study of hyperlipidemic patients, researchers found that canola oil
and olive oil reduced apolipoproteins B, A-I and Lp(a), total serum cholesterol,
low-density lipoprotein and the ratio between low-density and high-density
lipoprotein cholesterol to the same extent. However, there was a slightly greater
decrease in low-density lipoprotein cholesterol with the diet containing
rapeseed (canola) oil than with the olive oil diet. These two oils improved
intravenous glucose tolerance to a similar extent. [12]

BLOOD PRESSURE LOWERING EFFECTS

Canola oil may have benefits on blood pressure-lowering. [4]

ANTI-CANCER / ANTI-MUTAGENIC ACTIVITES

Canolol was recently reported to have benefits on lowering the risk of cell
mutation. Canolol suppressed ONOO(-)-induced bactericidal action. It also
reduced intracellular oxidative stress and apoptosis in human cancer SW480
cells when used at a concentration below 20 microM under H(2)O(2)-induced
oxidative stress. In addition, canolol suppressed plasmid DNA (pUC19) strand
breakage induced by ONOO(-), as revealed by agarose gel electrophoresis. [5]

HEART HEALTH / CARDIAC ARRHYTHMIAS

Regular substitution of canola oil for other dietary lipid sources may assist in
reducing the likelihood of a transient ischemic event leading to life-threatening
cardiac arrhythmias. In a study, researchers randomly assigned rats to one of
four experimental diet groups for 12 wk. The fat source in the diets was 12%
olive (63% oleic acid), canola (55% oleic, 8% alpha-linolenic acid), soybean
[50% linoleic 18:2(n-6), 7% alpha-linolenic acid] or sunflower seed oil (64%
linoleic acid). The researchers found that the incidence of ventricular fibrillation,
mortality and arrhythmia score during reperfusion were significantly lower in
rats fed the diet containing canola oil than in those fed other diets. [10]

Canola oil diet was found to have health benefits on heart tissues. In a study,
aged rats fed with canola oil diet was found to have a well-vascularized
myocardium, which is probably associated with preservation of numerical
density of the myocytes in the myocardium of these animals. [11] In another
study, aged rats fed with canola oil diet (rich in n-3 fatty acid) presented
morphological cardiovascular and metabolic changes less important in
magnitude than old animals and, mainly, the same age animals under
hyperlipidic diet. [13]

PLATELET FUNCTIONS

Canola oil has demonstrated its benefits on platelet functions in a trial. In this
study, researchers supplied 30 healthy male subjects with a
controlled-saturated-fatty-acid (baseline) diet for 3 wk and then consumed
either safflower oil or canola oil as a major fat source for 8 wk. The researchers
studied their platelet function and fatty acid composition. Compared with
baseline, the researchers observed a 35% decrease in arachidonic acid in
platelet phospholipids of the canola-oil diet group. And, both
unsaturated-fatty-acid diets reduced platelet aggregation at 3 wk of oil-based
diet feeding and only canola oil influenced platelet function (lowered ATP
secretion) at 8 wk. [9]

OVERDOSE, TOXICITY, SIDE EFFECTS AND OTHERS

A group of 9 dairy cattle accidentally ingested large volumes of canola oil.
Consequently, four of the animals died, and 3 were necropsied. [6]

Some health organizations do not recommend use of canola oil in infant
formula largely because of concerns over possible accumulation of triglyceride
in heart as a result of the small amounts of erucic acid (22:1n-9) in the oil. [8]

Ethalfluralin is a herbicide that is effective for weed control on a wide variety of
crops, including canola. Researchers analyzed samples from canola seed,
meal, and refined oil and they found no detectable residue of the herbicide. [7]

This Article is for your reference only. Consult with your doctor before using any
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REFERENCES
[1] Dupont J et al, Food safety and health effects of canola oil. J Am Coll Nutr. 1989 Oct;8(5):360-75. [2] Wakamatsu D et al,
Isolation, identification, and structure of a potent alkyl-peroxyl radical scavenger in crude canola oil, canolol. Biosci Biotechnol
Biochem. 2005 Aug;69(8):1568-74. [3] Chisholm A et al, Cholesterol lowering effects of nuts compared with a Canola oil enriched
cereal of similar fat composition. Nutr Metab Cardiovasc Dis. 2005 Aug;15(4):284-92. [4] Bierenbaum ML et al, Effects of canola
oil on serum lipids in humans. J Am Coll Nutr. 1991 Jun;10(3):228-33. [5] Kuwahara H et al, Antioxidative and antimutagenic
activities of 4-vinyl-2,6-dimethoxyphenol (canolol) isolated from canola oil. J Agric Food Chem. 2004 Jul 14;52(14):4380-7. [6]
Clark C et al, Toxic effects in dairy cattle following the ingestion of a large volume of canola oil. Can Vet J. 2001 Sep;42(9):721-3.
[7] Shackelford DD et al, Determination of ethalfluralin in canola seed, meal, and refined oil by capillary gas chromatography with
mass selective detection. J Agric Food Chem. 2000 Sep;48(9):4422-7. [8] Green TJ et al, Low erucic acid canola oil does not
induce heart triglyceride accumulation in neonatal pigs fed formula. Lipids. 2000 Jun;35(6):607-12. [9] Kwon JS et al, Effects of
diets high in saturated fatty acids, canola oil, or safflower oil on platelet function, thromboxane B2 formation, and fatty acid
composition of platelet phospholipids. Am J Clin Nutr. 1991 Aug;54(2):351-8. [10] McLennan PL et al Dietary canola oil modifies
myocardial fatty acids and inhibits cardiac arrhythmias in rats. J Nutr. 1995 Apr;125(4):1003-9 [11] Aguila MB et al Numerical
density of cardiac myocytes in aged rats fed a cholesterol-rich diet and a canola oil diet (n-3 fatty acid rich). Virchows Arch. 1999
May;434(5):451-3. [12] Nydahl M et al, Similar effects of rapeseed oil (canola oil) and olive oil in a lipid-lowering diet for patients
with hyperlipoproteinemia. J Am Coll Nutr. 1995 Dec;14(6):643-51. [13] Aguila MB et al, Morphological and biochemical
comparison among aged rats fed with hyperlipidic and canola oil diet Arq Bras Cardiol. 1997 Mar;68(3):155-61.

More about the adverse effects of canola oil:

Liu JW, Abbott Laboratories
Dietary supplementation of a high-gamma-linolenic acid canola oil (HGCO)
containing approximately 36% (w/w) of gamma-linolenic acid (GLA, 18:3n-6)
from the seeds of a genetically transformed canola strain, was assessed
for its long-term biological effects. Result Overall, long-term (12-week)
feeding with diets containing up to 15% HGCO resulted in no adverse effects
on growth, organ weight, hematology and serum biochemistry as compared
to the diet containing 15% borage oil. [J Agric Food Chem. 2004 Jun
16;52(12):3960-6.C]