Evening primrose oil doesn't reduce the symptoms of the
itchy skin problem eczema, according to a new review of studies.
Herbal supplement makers market primrose oil as helpful in
treating eczema, but "I don't think you'll get a specific benefit"
from the pills, said Dr. Joel Bamford, the lead author of the review. Eczema is
a common skin disorder, especially among children, marked by itchy, red skin. Commonly,
patients are prescribed steroid medications to treat the problem.
Primrose oil initially showed some promise in studies
several decades ago, said Bamford, who is an associate instructor at the
University of Minnesota Medical School in Duluth.
But when he tried to replicate the findings, he found that
primrose oil didn't seem to work. Since then, organisations such as the
National Institutes of Health and the American Academy of Dermatology have
largely brushed aside primrose oil as a treatment for eczema.
But makers of the supplement continue to market the oil as
beneficial for eczema. Evening primrose oil sells for about $14 (R126) for 100, 500-milligram pills. Dr.
Xiu-Min Li, a pediatrics professor at Mount Sinai School of Medicine and the
director of the Center for Chinese Herbal Therapy for Allergy and Asthma there,
said families are often looking for alternatives to steroids.
The medicines often work well, she said, but when patients
stop the treatment, the eczema comes back."It makes a family very, very
uncomfortable," she said. To get a better sense of what all the data have
to say about the oil, Bamford and his colleagues analysed the results of 19
studies that compared primrose oil to a fake pill, usually containing vegetable
oil or paraffin.
No difference between
placebo and primrose oil
Of seven studies that measured 176 patients' assessments of
their symptoms, there were no differences between those who took primrose oil
and those who took the placebo. Similarly, of the eight studies that measured
doctors' assessments of 289 patients' symptoms, there were also no differences
between the groups of patients, the researchers report in The Cochrane Library.
This isn't to say that people's eczema didn't improve in the studies.
Bamford says about 30% of patients might see their eczema
clear up for a time, but the same proportion of patients who take a placebo
will also see an improvement in their condition."Thirty percent will
improve because (eczema) comes and goes. It has nothing to do with taking the
primrose oil or taking the placebo. It has to do with time," Bamford told
Reuters Health. Li said she believes primrose has some potential to be
beneficial, even if that benefit is the same as a placebo.
"If there are some things, even if not as effective as
topical steroids, but that can help (patients) at a certain level, I think they
have a certain value," she said. She added that the evidence is not there,
however, to recommend that patients take the oil. Primrose oil is considered
safe, and Bamford said the studies did not reveal any side effects.
The oil carries a very slight risk of increased bleeding,
but Bamford said it's unlikely. Bamford said he would not recommend that his
patients take it even if it's harmless."Do you want to spend your money on
something that does not have any known effect?" he said.