EXPANDED VERSION: Evening Primrose Oil Versus Borage Oil
Udo Erasmus, PhD
I am often asked why I use evening primrose oil
rather than borage oil as a source of gamma-linolenic acid, or
GLA, in Udo's Choice Oil Blend. After all, borage oil is cheaper
and contains more than twice as much GLA as evening primrose oil,
so this would seem like the more logical choice. However, for me,
the quantity of GLA in oil and its price are not primary
deciding factors. Oil quality and the beneficial biological
activity of its GLA should take priority. While borage oil is widely
used in the marketplace as a source of GLA, my review of the research
literature suggests evening primrose oil may be preferable.
Physical Structure of the Oils
The oils from evening primrose and borage act
differently in the body because the oils themselves differ in several
ways. Evening primrose contains far more omega-6 essential fatty acids
and other beneficial 'minor ingredients' that play an important
role in fat metabolism, especially that of GLA. In other words,
GLA does not act alone in the body; it has help from other nutrients
within the oil itself. For this reason, although both evening primrose
and borage oil have been shown to improve some conditions such
as high blood pressure, some research shows that evening primrose
works better than borage, even though evening primrose actually
contains less GLA.
What Does the Research Show?
Far more research has been done on evening primrose
oil than borage oil. According to studies, the health-promoting
activity of evening primrose is superior to borage in several ways:
- In humans, evening primrose reduces the production of TxB2,
a substance that increases blood's clotting tendency, making
TxB2 a risk factor for stroke, embolism, and heart
attack. Borage oil, on the other hand, increases TxB2,
making clot formation leading to stroke, embolism, or heart attack
- Evening primrose oil decreases human platelet stickiness
(aggregation) of the blood, while borage oil increases
platelet stickiness, making a blood clot in an artery more
likely, thereby increasing risk of a stroke, heart attack,
- In animals and humans, evening primrose elevates a
substance in the body called DGLA, or dihomogamma-linolenic
acid, from which the hormone prostaglandin E (PGE1)
is made. PGE1 lowers cardiovascular risk factors,
and DGLA also takes part in reactions that result in
- In mice, evening primrose oil increases production of hormones
PGE1 and prostacyclin I2 (PGI2);
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). In
contrast, borage oil reduces PGI2 levels dramatically,
thereby lowering one of the body's main defenses against stroke
or heart attack.
- In rats with high blood pressure, both types of oil lower blood
pressure, but weight for weight, evening primrose oil is more
- Evening primrose oil reverses diabetic nerve damage in rats;
borage oil has little or no effect.
Toxicity of Evening Primrose and Borage
A search for toxicity of evening primrose came
up with the following statements: ".appears to be safe for
most people." ".has a very low toxicity." "Unrefined
evening primrose oil contains no known toxins." "Unlikely
to threaten life or cause significant symptoms."
Evening primrose oil has no known potentially
toxic effects. Borage oil, in contrast, might contain traces
of toxins always present in the borage plant and its seeds.
As protection against being eaten, borage plants make natural
toxins called pyrrolizidine alkaloids (PAs). Traces of PAs,
found as 'minor ingredients' in borage seeds, might end up
in borage oil. These toxic alkaloids accumulate in body tissues
over time and can result in cancer, damage to the liver,
kidney, gastrointestinal tract and respiratory system, and
other serious problems.
Actual measurements of PAs have remained elusive
for several reasons. First, any substance present below the detection
limit of the test used cannot be measured. Second, few tests have
been carried out, and fewer have been published. Third, although
every batch of borage oil should be tested for PAs, manufacturers
and distributors do not usually do this.
So, are pyrrolizidines present in borage oil?
Consumers don't know. The presence of undetectable quantities is
likely. One borage oil supplier has assured the public that pyrrolizidine
alkaloids "have NEVER been found in borage seed oil." Aside
from being untrue, because PAs have been found in borage oils,
the statement implies absence of PAs, non-toxicity, and (therefore)
safety for human consumption. However, several reputable sources,
including the Canadian Pharmacy Journal and Tyler's Herbs
of Choice: the Therapeutic Use of Phytomedicinals, have expressed
concerns regarding the safety of borage oil.
Is Refined Any Better?
If unrefined borage oil contains traces of toxic
PAs, refining borage oil largely removes them. Unfortunately, refined
oil production requires treatment with NaOH (sodium hydroxide),
then H3PO4 (phosphoric acid), then bleaching
clays (which render oil rancid, imparting bad odor). To remove
the bad odor (deodorize), oils are then heated up to 450�F (230�C).
Both toxic and beneficial minor ingredients are removed from oils
This process used to make refined, bleached or
deodorized oils changes some molecules from natural and beneficial
to unnatural and toxic. In other words, unrefined borage oil may
contain one kind of toxin, while refined borage oil contains other
kinds of toxins.
Evening primrose and borage oils are not comparable.
They are not mutually interchangeable. Their structural makeup
is different. Research has shown differences in their chemistry
and actions. Their potential for toxic effects is also different.
I take the cautions regarding borage oil seriously.
There are unanswered questions regarding its safety. No one knows
the cumulative effects of long-term use. This is why I prefer to
err on the side of caution and don't use either unrefined or refined
borage oil in any of my products. Instead, I choose expeller-pressed, unrefined evening
primrose oil from organically grown seeds-which contains no PAs
or toxins-for Udo's Choice Oil Blend.
Most unrefined oils contain beneficial oil-soluble 'minor
ingredients' that come from the oil seeds, including vitamin E,
carotene, phytosterols, lecithin, polyphenolic antioxidants, and
many others. These minor ingredients are removed from oils by intensive
processing to produce refined, bleached, deodorized, colorless,
odorless, and tasteless oils. The minor ingredients in unrefined evening
primrose oil are good for health and should remain in the oil.
The Fat Basics
Essential fatty acids (EFAs) are substances from fats that
must be provided by foods because the body cannot make them, but
must have them for health. EFAs exist in two families: omega-3s (also
known as ALA, alpha-linolenic acid) and omega-6s (LA, or linoleic acid).
From these two, the body makes several derivatives, hormones, and
other active substances.
Omega-3 fatty acids include:
- ALA (alpha-linolenic acid; abundant in flax, and present in
small quantities in hemp, walnut, soybean, and canola). Given
enough ALA to start with, the body converts ALA into SDA, EPA,
and DHA in various tissues, according to need;
- SDA (stearidonic acid; present in a few exotic seeds);
- EPA (eicosapentaenoic acid; used in hormone production; found
in fish oils);
- DPA (docosapentaenoic acid);
- DHA (docosahexaenoic acid; the major brain omega-3; also found
in the eyeball (retina), red-brown algae, and fish oils).
Omega-6 fatty acids include:
- LA (linoleic acid; abundant in safflower, sunflower, and corn;
present in medium quantities in soybean, sesame, pumpkin seed,
and almond; present in small quantities in canola, peanut, and
olive). given enough LA to start with, the body converts LA into
GLA, DGLA, and AA in various tissues, according to need;
- GLA (gamma-linolenic acid; present in evening primrose oil);
- DGLA (dihomogamma-linolenic acid; used in hormone production);
- AA (arachidonic acid; the major brain omega-6; used in hormone
production; found in meat, eggs, and dairy products).