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PART 1: Abbreviations Used in this Article
CLA: conjugated
linoleic acid, a trans- fatty acid made from
the omega-6 essential linoleic acid by bacterial or industrial
partial
hydrogenation, or by high-temperature industrial processing.
CLA, made by a bond shift and a twist of the molecule,
is not a nutrient that is 'essential' for health.
EFA: essential fatty acid, one of
two fatty acids (omega-6 and omega-3) that are 'essential' to the
body, which means that:
-
The body cannot make them;
-
It must have them for health to be possible;
and
-
The body must
therefore
obtain 'essential' fatty
acids
from foods or supplements.
In addition to the 2 EFAs, 20 minerals,
13 vitamins, and 8 amino acids from proteins are also 'essential' for
health by the above definition. Omega-6: omega-6, the name
by which all members of one family of essential fatty acids is identified.
The members include linoleic acid (LA), gamma-linolenic acid (GLA),
dihomogamma-linolenic acid (DGLA), and arachidonic acid (AA). LA: linoleic
acid, the omega-6 essential fatty acid, from which
the body makes several derivatives with important functions,
including GLA, DGLA,
and AA. DGLA and AA are the starting points for making
hormone-like
Series 1 and Series 2 eicosanoids (formerly called 'series 1 and
series 2 prostaglandins'). AA is also required for the
development and function of the brain. Omega-3: omega-3, the
name by which all members of the other family of essential fatty
acids is identified. The members of the omega-3 family include alpha-linolenic
or ALA or LNA), stearidonic acid (SDA), eicosapentenoic acid (EPA),
and docosahexaenoic acid (DHA).ALA: alpha-linolenic
acid, the omega-3 essential fatty acid, from which
the body makes several derivatives with important functions,
including SDA, EPA,
and DHA. EPA is the starting point for making hormone-like
Series
3 eicosanoids (formerly called 'series 3 prostaglandins').
DHA is required for brain development and brain function.
Introduction
CLA has attracted a lot of attention over the past few years, some through the
media, but far more through health and fitness magazines. Many claims for benefits
have been made for CLA, from weight loss, to antioxidant, anti-cancer and, more
recently, to diabetes and cardiovascular disease as well. Is CLA all it's been
cracked up to be? This article addresses that question.
Research Studies Of 139 references pulled off MedLine in June of
2001, 29 were published in 2001; 65 in 2000; 33 in 1999; and 15 in 1998. Of these
139 references, the following is a breakdown of topics:
- 10 were production-oriented studies.
- 6 were reviews, (i.e., these are not studies).
- 14 were studies about how to get CLA into different foods.
One of these came to the brilliant conclusion that cows eating
grass (their natural food) contained a better fatty acid (n3: omega-6)
profile and more CLA than cows fed concentrates from bags. Wow!
What a stunning discovery!1
- 2 were molecular studies.
- 24 were studies using cell cultures.
- 69 were studies performed on animals.
- 14 studies were carried out on humans.
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Of these research studies, those carried
out in living animals and humans (in vivo) are more likely than studies
carried out in various normal and abnormal animal and human tissue
cultures (in vitro studies) to show how CLA actually affects human
health and disease. And, it is important to note that, while CLA
is being 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.
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