High levels of cholesterol can be
harmful, and they can increase a person's risk of serious cardiovascular
events, such as heart attack or stroke. A high-fat diet can contribute to
raised cholesterol levels, but some researchers say that ingesting a specific
type of oil may prevent this negative effect.
A new study compares the effects of
cottonseed oil and olive oil on cholesterol levels.
Generally speaking, there are two
types of cholesterol: high-density lipoprotein (HDL) cholesterol, also known as
"good" cholesterol, and low-density lipoprotein (LDL) cholesterol,
which people describe as "bad" cholesterol.
Healthcare professionals often refer
to LDL cholesterol as "bad" because the overaccumulation of this
fatty substance can interfere with blood circulation and increase a person's
risk of heart attack or stroke.
Conversely, they tend to say that
HDL cholesterol is "good" because it helps remove LDL cholesterol
from the body. It does this by taking the LDL cholesterol to the liver, which
will break it down and process the resulting waste.
In order to prevent LDL cholesterol
from reaching high levels in the blood, specialists advise people to adhere to
diets that promote high HDL and low LDL cholesterol.
However, researchers from the
University of Georgia in Athens have found that adding cottonseed oil to a
high-fat diet can actually decrease a person's LDL cholesterol levels.
The study paper reporting these results appears in the
journal Nutrition Research.
Pitting
cottonseed oil against olive oil
The researchers worked with a group
of 15 male participants aged 18–45 who were within healthy weight ranges. They
asked the participants to follow one of two versions of a high-fat diet, each
of which included a particular component.
In one version of the diet, the
researchers used olive oil to enrich the meals. In the other, they used
cottonseed oil instead. All of the participants adhered to their assigned diet
for a period of 5 days.
After
comparing the effects of the two diet regimens on the participants, the
investigators found that those who had followed the cottonseed oil-enriched
diet had lower LDL cholesterol and triglyceride levels.
Conversely, the participants who had
followed the olive oil-enriched diet saw no significant changes.
"One of the reasons these
results were so surprising is because of the magnitude of change observed with
the cottonseed oil diet," says study author Jamie Cooper, an associate
professor at the University of Georgia.
"To see this amount of change
in such a short period of time is exciting," she adds.
Effects on
LDL vs. HDL cholesterol levels
The individuals on the cottonseed
oil-enriched diet saw, on average, a decrease of approximately 8 percent in
total cholesterol levels. Their LDL cholesterol levels decreased by 15 percent
on average, and their triglyceride levels decreased by 30 percent.
As for the levels of HDL
cholesterol, these actually increased by about 8 percent for individuals on the
cottonseed oil-enriched diet.
The researchers speculate that a
specific type of fatty acid called dihydrosterculic acid, which is present in
cottonseed oil but not in olive oil, may prevent triglyceride accumulation.
"By
doing that," Cooper explains, "it pushes the body to burn more of
that fat because it can't store it properly, so you have less lipid and
cholesterol accumulation."
Cooper also suggests that the
polyunsatured fats and omega-6 that are abundant in cottonseed oil may have
beneficial effects.
The authors explain that several
sponsors — including the nonprofit company Cotton Incorporated, the University
of Georgia Clinical and Translational Research Unit, and the Augusta University
and University of Georgia Medical Partnership — financially supported the
recent study.
In the future, the investigators aim
to learn more about the effects of cottonseed oil on health by recruiting older
participants who already have high cholesterol levels and extending the dietary
intervention period.
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