Conjugated linoleic acid, or CLA, has attracted a lot of attention
over the past few years. Many claims for benefits have been made-from
enhancing weight loss and providing antioxidant protection to treating
diabetes and cardiovascular disease. But is CLA all it's cracked
up to be?
Conjugated linoleic acid is one or more of 8 possible
twisted trans fatty acids created from linoleic acid,
also known as omega-6 essential fatty acid (EFA). In nature, the
conversion of linoleic acid into CLA occurs naturally in the
stomachs of cows, goats, sheep and other cud-chewing animals;
accordingly, CLA is found in the meat and milk fat of these species.
Butter, for example, normally contains about 5 mg of CLA per
gram of fat.
CLA is also sold in supplement form. To achieve
this, omega-6 fatty acids are processed,
during which the original molecular structure of the fat is twisted
into a different shape. The result is called a trans fat,
and as more and more people are becoming aware, trans fats
do not have the same desirable effects on health as essential
fatty acids. In fact, CLA interferes with the conversion of EFAs
(both omega-6s and omega-3s) to derivatives necessary for hormone production.
CLA is not essential. Unlike omega-3s and omega-6s, without
which we cannot live, we could live healthfully on a CLA-free
diet our entire life.
The body has no requirement for CLA. But the body
has an absolute requirement for EFAs, which should not be interfered
CLA is touted for many human problems, there are relatively few
human studies to draw on. Unfortunately, a
substantial number of these studies indicate that CLA does not
do in human studies what it appears to do in animal studies.
Some animal studies suggest that CLA can
perform antioxidant functions and might have anti-cancer, anti-inflammatory,
anti-diabetic, and cardio-protective properties. Other studies
suggest that CLA actually increases oxidation of cells, which
is not so good and carries a warning about the possible worsening
of some degenerative conditions. Besides, if one wants antioxidant
protection, there are hundreds of substances with antioxidant
activity equal to or better than CLA, including vitamin A, beta-carotene
and vitamin E. In addition, about half of all edible green plants
contain hundreds of different anti-cancer, cardio-protective,
anti-diabetic, anti-inflammatory ingredients.
At the CLA doses used in human studies,
the research results are quite disappointing. Most human studies find no benefits
for the degenerative conditions for which CLA is recommended:
weight loss, impaired immune and antioxidant function, and cardiovascular
problems. The usual doses of CLA used in animal studies greatly
exceed those used in human studies. This may explain why animal
studies come up with better results than human studies, and may
also explain the negative effects of CLA on liver and insulin
in rats, and the changes in yolk quality and hatchability in
eggs. So, there appears to be a dose-related shadow side to CLA.
Remove the shadow by lowering the dose, and the benefits also
It seems that CLA
is highly overrated in terms
of human health benefits. More sizzle than steak, as the saying
goes. To effectively treat human diseases for which CLA showed
benefits in animals, larger doses than are normally available
in food (cream, butter) or supplement form would be needed.
Based on several calculations, five per
cent CLA, the highest dose used in animal studies, would convert to 35
and 21 grams of CLA for men and women, respectively. This would
be 2.5 tablespoons of CLA for men, and 1.5 tablespoons for women.
These high doses are unaffordable for many at today's prices,
making it impossible to provide effective doses to those who
have problems CLA might address. Even worse, we have to consider
the negative effects associated with higher doses of CLA in animals.
At these high doses, similar negative effects would likely occur
in humans as well. In contrast, the same daily intakes-or even
higher (up to 10 tablespoons per day)-are appropriate for the
more important and more affordable omega-3 and omega-6 EFA mixtures.
Being far less expensive than CLA, such oils can be taken in
the 30 to 150 gram/day range over the long term, and confer all
of the health benefits hyped for but not delivered by CLA.
of using CLA, we need to focus on getting enough EFAs. Essential fatty
acids cannot be made by the body but, because they are necessary for the
normal (healthy) functioning of every cell, tissue, gland, and organ, they
must therefore be provided by foods.
There are two kinds of EFAs: omega-3s and omega-6s. Most
people don't get enough omega-3s. People who use flax oil exclusively
as the source of EFAs in their diet often don't get enough omega-6s.
Those who follow low-fat or no-fat diets are even more at risk
of having both EFA deficiencies.
It is important to obtain both EFAs and in the
most beneficial ratio, which we find to be two omega-3s to each omega-6.
These EFAs should come from organically grown oils that retain
their health-promoting 'minor ingredients', which include antioxidants,
phytosterols, lecithin, and other oil-soluble molecules present
in seeds and nuts.
Since EFAs are easily destroyed by light, oxygen,
and heat, EFA-rich oils should be made and stored under protection
from these destructive influences, and should not be used during
high heat cooking in the home. While they can be used in hot
soup or on steamed vegetables, they should not be fried, deep-fried,
or even sautéed.
approach is part of the 'The Right Fat Diet®',
a food program emphasizing green vegetables, the best fats (EFAs)
in the right ratio and made, packaged, stored and used properly,
and proteins as the foundation for good health. To make sure
that digestion works effectively, we also recommend digestive
enzymes with meals. The Right Fat Diet® lowers most cardiovascular
risk factors, provides the EFAs essential for insulin function,
inhibits fat production and enhances fat burning, promotes
healthy fat loss, increases caloric burning, and improves insulin
The Right Fat Diet® also improves brain function and mood, inhibits cancer,
enhances bone mineral retention, improves protein retention, improves skin
beauty, increases energy, stamina, performance, recovery, and healing of injuries,
and improves thyroid, adrenal, and reproductive gland functions. Further, The
Right Fat Diet® decreases inflammation, improves digestion, reduces allergy
symptoms, and decreases the problems of autoimmune conditions.
Finally, The Right Fat Diet® enhances food flavors, suppresses appetite,
and improves the absorption from food containing healthful oil-soluble phytonutrients.
All of the benefits touted for CLA (and more) are more effectively provided
by good old EFAs. That's why we use the following slogan: "Forget CLA
and remember EFA."
CLA: conjugated linoleic acid
, a trans
acid made from omega-6 essential linoleic acid by bacterial hydrogenation
(cows and other ungulates), or industrial partial hydrogenation (margarines,
shortenings, partially hydrogenation vegetable oil). CLA can also
be made by exposing linoleic acid to very high temperatures. CLA
is not a nutrient 'essential' for health. Nor are its benefits in
animals substantiated in human clinical trials..
EFA: essential fatty acid
, one of
two fatty acids (omega-3 and omega-6) that are 'essential'
which means that 1) the body cannot make them, 2) the
body needs them for good health, and 3) the body must
therefore obtain 'essential' fatty acids from foods or