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PART
2: Introduction
I
am often asked why I use Evening Primrose Oil (EPO) rather
than Borage Oil (BO) as a source of GLA in Udo's Choice Oil
Blend. BO is cheaper and contains more than twice as much GLA
as an equal amount of EPO.
I
could use BO in the blend if I wanted to do so. Why don't I?
For
me, the quantity of GLA in oil and its price are
not the primary deciding factors. Oil quality and the biological
activity of its GLA should take priority. While
BO is widely used in the marketplace as a source of GLA, a
review of the research literature suggests that EPO may be
preferable.
Let
me share with you some of the research literature I have seen
on EPA and BO.
Physical Structure of the Oil
The
oils from EPO and BO act different in the body because they
differ in several ways:
- The
GLA found in different seed oils is linked to the carbons
of glycerol in different locations, forming different triglyceride
(positional) isomers1,2, which may differ in activity.
GLA is found mainly on the outside carbons of glycerol in
EPO, but on the middle carbon of glycerol in BO. This may
affect the way in which the GLA functions in the body.
- GLA
can be partnered with different fatty acids in a triglyceride
molecule1, that may also affect how GLA functions
in the body.
- EPO
contains far more omega-6 essential fatty acid (LA) than BO does.
This difference may affect GLA function1.
- The 'minor
ingredients' in EPO are quite different from those in BO.
These minor ingredients may affect and modify the activities
of the GLA and the oil itself, and can yield dramatic differences
in how the GLA molecule functions in the body1.
- BO
contains erucic acid (22:1) and even longer chain monounsaturates
(24:1), which may affect the action of the oil. By the way,
these long chain fatty acids can also be used to confirm
whether an EPO product has been adulterated with cheaper
BO3.
In
other words, GLA does not act alone. Like EPO, BO does improve
some conditions. But in other conditions, research shows that
EPO works better than BO does, even though EPO contains less
GLA. Some of that research follows.
Research
Far
more research has been done on EPO than on BO. A search of
PubMed-Medline in July 2001 came up with 375 published studies
on EPO. The same search engine listed only 71 studies done
on BO.
According
to studies, the health-benefiting activity of EPO in humans
and animals is superior to that of BO in several respects:
- In
a human study, EPO was shown to benefit health by reducing
the production of TxB2. TxB2 increases
the blood's clotting tendency, making it a risk factor for
stroke, embolism, and heart attack. EPO's ability to lower
TxB2 makes EPO protective against these cardiovascular
risk factors. BO, on the other hand, increased TxB2,
making clot formation leading to stroke, embolism, or heart
attack more likely4.
- EPO
decreased human platelet stickiness (aggregation). BO increased
platelet stickiness, making a clot in an artery more likely,
thereby increasing risk of a stroke, heart attack, or embolism
occurring.
- In
animals and humans, EPO elevates DGLA, from which prostaglandin
E1 (PGE1), an eicosanoid hormone made
from fats, which lowers cardiovascular risk factors5.
DGLA also takes part in reactions that result in decreased
inflammation5.
- In
mice, EPO increased PGE1 and Prostacyclin I2 (PGI2)
production6. These two open up small blood vessels,
increase blood supply to tissues, lower blood pressure, reduce
inflammation pain and swelling, and reduce clot formation
(platelet aggregation). BO reduced PGI2 levels
dramatically, lowering one of the body's main defenses against
stroke or heart attack6.
- In
rats with high blood pressure (spontaneously hypertensive),
both EPO and BO can lower blood pressure, but weight for
weight, EPO is more effective7.
- EPO
reverses diabetic nerve damage in rats. BO has little or
no effect8.
These research findings also appear in other publications. One of these is Principles
and Practice of Phytotherapy: Modern Herbal Medicine. In that book, the
following statements are found:
- "Although
GLA has been found in higher concentrations from other sources,
including borage oil, black currant oil and fungal lipids,
there is currently less evidence to support their clinical
efficacy compared to EPO."9
- "Evening
primrose oil outperformed black currant oil, borage oil,
and fungal oils in ameliorating nerve conduction velocity
deficits in diabetic rats."9
Another
is Dr. Andrew Weil's Integrative Medicine's onemedicine web
site, which is aimed at medical professionals who need solid
information on alternative treatments. Here is a quote from
the Integrative Medicine web site:
- "GLA
is available directly from evening primrose oil (7% to 10%
GLA), black currant seed oil (15% to 20% GLA), borage oil
(18% to 26% GLA), and fungal oil (23% to 26% GLA). GLA bioavailability
may be related to the precise triacylglycerol composition.
Although the GLA concentration in borage oil appears to be
twice as high as in evening primrose oil, research has shown
that the GLA effects, such as formation of prostaglandin
E1, are comparable for both on a gram-for-gram
basis."10
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