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CLA: A Source of Optimism in the Battle of the Bulge
by Michael T. Murray, N.D.
The nutritional supplement CLA (conjugated
linoleic acid) is a slightly altered
form of the essential fatty acid linoleic
acid that is showing tremendous promise in
the promotion of good health. CLA is found
naturally occurring in meat and dairy products
when the cattle and cows consume a diet
rich in grasses. Now that livestock are primarily
grain fed, the CLA has virtually disappeared
out of dairy products and the meat we
consume. As a result, we may be increasing
our risk for obesity, heart disease and even
cancer.
Who discovered CLA?
CLA was discovered in 1978 when Michael
Pariza, Ph.D. and other researchers at the
University of Wisconsin were seeking to find
possible cancer-causing compounds in meat.
Instead, they found an anticancer compound—CLA. In preliminary animal and
test tube studies, CLA has shown evidence
that it might reduce the risk of cancers at several
sites, including breast, prostate, colorectal,
lung, skin and stomach. Whether
CLA will produce a similar protective effect
in humans has yet to be determined but
researchers are optimistic.
What has the research on CLA shown?
Over 200 studies have shown that CLA may
play a very important role not only against
cancer, but also in helping fight diabetes,
obesity and hardening of the arteries (atherosclerosis).
Particularly exciting for many is
the research showing that CLA supplementation
can help promote weight loss.
Researchers from the University of
Wisconsin recruited 80 obese people and had
half of them take 3,000 mg of CLA daily,
while the other half took a placebo. They
were all put on a diet program and encouraged
to exercise. Weight loss was about the
same for both groups, an average of five
pounds. So, why take CLA? Those taking
CLA reported less fatigue, dizziness and
nausea than those on the placebo. But the
real advantage was while the people taking
the placebo put the weight back on mainly as
fat, the people taking CLA who put weight
back on put it on primarily as lean muscle
and not fat. In other words, CLA promoted
an increase in lean muscle mass and a
decrease in percentage of body fat. Similar
results were found in a study conducted at
Lund University in Sweden.
The latest study from the University of
Sweden showed that CLA helps prevent the
regaining of body fat among those taking the
supplement for two years. This study is a
one-year continuation of the original 12-
month, double-blind, placebo-controlled
study of 180 overweight subjects. In the first
year, subjects were randomized in one of the
following groups: placebo (olive oil), or CLA.
In the second 12-month phase of the study,
all subjects took CLA supplements as triglycerides.
CLA supplementation prevented subjects
in the two CLA groups from regaining
the eight percent of body fat they lost in the
first year. The participants that had been on
a placebo the first year and then took CLA
for 12 months experienced a five percent
reduction in body fat.
This new research adds an important new
dimension to the numerous studies on CLA
showing significant long-term benefits and
safety.
Most of the studies have used the Tonalin
brand of CLA that is extracted through a
proprietary process that converts linoleic
acid from safflowers into CLA. Tonalin provides
the highest CLA activity available at
80 percent.
How does CLA work to promote and
maintain weight loss?
Researchers believe that CLA helps block fat
cells that are in the body from filling up with
fat by interfering with a fat-storing enzyme
known as lipoprotein lipase as well as by
increasing the sensitivity of cells to the hormone
insulin. CLA is also believed to help
burn fat by revving up muscle metabolism
and helping increase lean muscle mass. The
more muscle you have, the more calories
your body uses in order to function, thereby
speeding up the fat burning process.
Can you get all the CLA you need from
your diet to produce these effects?
No, in fact to get the level of CLA used in
these studies (1,000 mg with meals three
times daily), you would have to eat about
5.81 pounds of fresh ground beef, 53 ounces
of American cheese or 1.73 gallons of vanilla
ice cream. Simply stated, you cannot get the
amount of CLA needed for weight loss from
your diet. Fortunately, scientists are able to
convert the linoleic acid of pure safflower oil
into CLA to make it available as a nutritional
supplement.
Are there any side effects or drug interactions?
No side effects or drug interactions have
been reported with CLA supplementations.
Since the effects of CLA during pregnancy
and lactation have not been sufficiently evaluated,
it should not be used during these
times. TH
Michael T. Murray, N.D., is the director of
product development and education for
Natural Factors and is widely regarded as
one of the world’s leading authorities on
natural medicine. He is a graduate, faculty
member and serves on the Board of Trustees
of Bastyr University in Seattle, Washington.
He has written over 20 books including the
best-selling Encyclopedia of Natural
Medicine.
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