Gamma-linolenic acid (GLA) is
an omega-6 fatty acid that is found mostly in plant based oils such as
borrage seed oil, evening primrose oil, and black currant seed oil.
Omega-6 fatty acids are considered essential fatty acids: They are
necessary for human health, but the body can' t make them -- you have to
get them through food. Along with omega-3 fatty acids, omega-6 fatty
acids play a crucial role in brain function, as well as normal growth
and development. Also known as polyunsaturated fatty acids (PUFAs), they
help stimulate skin and hair growth, maintain bone health, regulate
metabolism, and maintain the reproductive system.
There
are several different types of omega-6 fatty acids. Most omega-6 fatty
acids in the diet come from vegetable oils in the form of linoleic acid
(LA). The body converts linoleic acid to GLA and then to arachidonic
acid (AA). GLA can be gotten from several plant based oils including
evening primrose oil, borage oil, and black currant seed oil. Most of
these oils also contain some linoleic acid.
A
healthy diet contains a balance of omega-3 and omega-6 fatty acids.
Omega-3 fatty acids help reduce inflammation, and some omega-6 fatty
acids tend to promote inflammation. The typical American diet tends to
contain 14 - 25 times more omega-6 fatty acids than omega-3 fatty acids.
Many nationally oriented physicians blame this high rate of omega-6 to
omega-3 fatty acids for the preponderance of inflammatory diseases in
society.
Not all omega-6
fatty acids behave the same. Linoleic acid and arachidonic acid (AA)
tend to be unhealthy because they promote inflammation. GLA, on the
other hand, may actually reduce inflammation.
Much
of the GLA taken as a supplement is converted to a substance called
DGLA that fights inflammation. Having enough of certain nutrients in the
body (including magnesium, zinc, and vitamins C, B3, and B6) helps
promote the conversion of GLA to DGLA.
Many
experts find the science supporting the use of omega-3 fatty acids to
reduce inflammation and prevent diseases to be much stronger than that
supporting GLA.
Some preliminary clinical research suggests that GLA may be useful for the following conditions:
- Diabetic neuropathy
Some
studies show that taking gamma linolenic acid (GLA) for 6 months or
more may reduce symptoms of nerve pain in people with diabetic
neuropathy. People who have good blood sugar control may find GLA more
effective than those with poor blood sugar control.
- Rheumatoid arthritis
Studies
are mixed as to whether evening primrose oil helps reduce symptoms of rheumatoid arthritis. Some preliminary evidence suggests evening
primrose oil may reduce pain, swelling and morning stiffness, but other
studies have found no effect. When using GLA for arthritis symptoms, it
may take 1 - 3 months to see any benefit. It is unlikely that evening
primrose oil would help stop progression of the disease, so joint damage
could still occur.
- Allergies
GLA
from evening primrose oil or other sources has a longstanding history
of folk use for allergies. And women and children who are prone to
allergies appear to have lower levels of GLA in breast milk and blood.
- Attention deficit/hyperactivity disorder (ADHD)
Clinical
studies suggest that children with ADHD have lower levels of essential
fatty acids (EFAs), both omega-6s and omega-3s. EFAs are important to
normal brain and behavioral function. Some studies suggest that taking
fish oil (containing omega-3 fatty acids) may help reduce ADHD symptoms.
- Breast cancer
One
study found that women with breast cancer who took GLA had a better response to tamoxifen (a drug used to treat estrogen sensitive breast
cancer) than those who took only take tamoxifen.
- Eczema
Evidence
is mixed as to whether evening primrose oil can help reduce symptoms of eczema.Some early studies found it did, but they were not well
designed. Later studies that examined people who took evening primrose
oil for 16 - 24 weeks found no improvement in symptoms. If you want to
try evening primrose oil, talk to your health care provider about
whether it is safe for you to try.
- High blood pressure (Hypertension)
There
is some preliminary evidence that GLA may help reduce high blood
pressure, either alone or in combination with the omega-3 fatty acids
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in
fish oil. In one study, men with borderline high blood pressure who took
6g of blackcurrant oil had a reduction in diastolic blood pressure
compared to those who took placebo.
Another
study examined people with intermittent claudication, pain in the legs while walking that is caused by blockages in the blood vessels. Those
who took GLA combined with EPA had a reduction in systolic blood
pressure compared to those who took placebo. More research is needed to see whether GLA is truly effective for hypertension.
- Menopausal symptoms
Evening
primrose oil has gained popularity as a way to treat hot flashes
associated with menopause, but so far studies have not shown that it
works. If you want to try evening primrose oil for hot flashes and night
sweats, ask your health care provider whether it is safe and right for
you.
- Mastalgia
Some
evidence suggests that evening primrose oil may reduce breast pain and tenderness in people with cyclic mastalgia. It may also help reduce
symptoms to a lesser extent in people with non cyclic mastalgia.
However, it does not seem to be effective for severe breast pain.
- Osteoporosis
Some
studies suggest that people who don' t get enough of some essential
fatty acids (particularly EPA and GLA) are more likely to have bone loss
than those with normal levels of these fatty acids. In a study of women
over 65 with osteoporosis,those who took EPA and GLA supplements had
less bone loss over 3 years than those who took placebo. Many of these women also experienced an increase in bone density.
- Premenstrual syndrome (PMS)
Although
most studies have found no effect, some women report relief of PMS symptoms when using GLA. The symptoms that seem to be helped the most
are breast tenderness and feelings of depression, as well as
irritability and swelling and bloating from fluid retention.
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