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Canola Oil Has a Greater Effect
on Cholesterol in Comparison to Other Monounsaturated Oils
High levels of blood cholesterol, specifically LDL
cholesterol ("bad" cholesterol) constitute a major risk factor
in the development of coronary heart disease (CHD). More recent studies
have demonstrated that oxidation (breakdown) of LDL results in changes
to the LDL particle that can ultimately increase its atherogenicity.
Diets high in monounsaturated fats (MUFA) have been shown to not only
reduce both total and LDL cholesterol, but also have the ability to
protect LDL against oxidation (Castro, P., et. al. 2000). Good news
for canola oil users! Research has established that canola oil has a
more potent total and LDL cholesterol lowering effect when compared
to other MUFA containing oils (Castro, P., et. al.) 2000. Canola oil
also protects against LDL oxidation to a greater degree that most commonly
used vegetable oils that are high in polyunsaturated fat (PUFA).
In the distant past, the connection between dietary
fat, cholesterol, and risk for CHD focused upon saturated (SFA) and
PUFA. For nearly 30 years the common belief was that SFAs raised cholesterol
levels, PUFAs lowered cholesterol levels, and MUFAs were neutral in
their effects. However, in the mid 1980s exciting research was published
showing that MUFAs, primarily as oleic acid, were as effective as PUFAs
in reducing both total plasma and LDL cholesterol. Good sources of MUFA
include olive oil (75%), canola oil (61%), corn oil (29%), soybean oil
(23%), sunflower oil (16%), and safflower oil (14%).
As the science in this area evolved, it was found
that not all MUFA containing oils are created equal in regard to their
effects on cholesterol lowering. In 1998 two scientists, Truswell and
Choudhury, compared the results of three separate human clinical trials
in which diets high in palmolein (an oil high in SFA and low in MUFA)
were compared to those high in MUFAs including olive, canola, and high
oleic sunflower. Of significance, canola oil produced the most dramatic
reduction in both total and LDL cholesterol values in comparison to
palmolein. Surprisingly, olive oil did not lower either total or LDL
cholesterol when compared to palmolein.
These results clearly demonstrate that not all MUFA
containing oils are the same in terms of health benefits! These findings
also demonstrate that once again canola oil comes out on top. An explanation
for the favorable effects of canola oil on blood cholesterol levels
revolve around the nutritionally beneficial fatty acid profile of canola
oil in comparison to other high MUFA oils (McDonald, B. 1999). Canola
oil contains one of the lowest concentrations of saturated fat (7%)
of all MUFA containing oils. In addition to canola's high MUFA content
mentioned above, it is also a good source of the omega-3 fatty acid
alpha-linolenic acid (ALA) (11%). Studies have shown that ALA is equally
as effective as oleic acid and linoleic acid in reducing both total
plasma and LDL cholesterol levels. Finally, canola oil is a good source
of vitamin E in comparison to other high MUFA and common vegetable oils.
Vitamin E, along with MUFAs, plays a crucial role in protecting the
LDL particle against oxidation, which ultimately reduces its atherogenicity.
Thus, the decision is clear - choosing canola oil and incorporating
it into your daily dietary regime is clearly a heart smart choice!
Truswell, A.S. 1998. Review - Monounsaturated oils
do not all have the same effect on plasma cholesterol. Eur. J. Clin.
Nutr. 52:312-315.
Castro, P., et. al. 2000. Consumption of and oleic
acid enriched-diet vs NCEP-I diet on LDL susceptibility of oxidative
modifications. Eur. J. Clin. Nutr. 54:61-67.
McDonald, B. 1999. Canola Oil: Nutritional Properties.
Canola Council of Canada Website www.canola-council.org.
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