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Posted Mar 9, 2006 8:12 AM
Evening Primrose Oil
Claims, Benefits: Cures, treats, or prevents practically everything—from rheumatoid arthritis, breast pain, hot flashes, premenstrual syndrome, eczema, and other skin problems to diabetic neuropathy, cancer, high blood cholesterol levels, and heart disease.
Bottom Line: Nearly all the claims are unproven. Might be worth trying for rheumatoid arthritis, but talk to your doctor first.
Full article, Wellness Letter, November 2003:
Down the Evening Primrose Path
In the Guide to Supplements on our website, evening primrose oil draws more visitors than any other page. Readers send us a lot of queries about it and about borage oil, a similar supplement, made from the seed of the borage plant, a common weed. It’s claimed that evening primrose oil and the less expensive borage oil cure, treat, or prevent practically everything—from rheumatoid arthritis, breast pain, hot flashes, premenstrual syndrome, eczema, and other skin problems to diabetic neuropathy, cancer, high blood cholesterol levels, and heart disease. So why not go ahead and take some, just for good measure?
Evening primrose, a small yellow wildflower (Oenothera biennis), has been used medicinally for centuries. The oil, pressed from the seed, is rich in linoleic acid, an essential fatty acid (EFA). "Essential" means that we have to consume the nutrient because the body does not produce it. Fortunately, EFAs are plentiful in foods, notably nuts and seeds. These polyunsaturated fats are good fats, unlike the saturated fats that contribute to heart disease.
Evening primrose oil also supplies another fatty acid, known as gamma-linolenic acid, GLA (not to be confused with alpha-linolenic acid, which is one of the omega-3 fatty acids). Borage oil, too, is high in GLA, as is black currant oil. You actually don’t need to consume this particular fatty acid, because your body synthesizes GLA from linoleic acid and converts it to hormone-like chemicals important in processes such as controlling inflammation, clotting the blood, and synthesizing cholesterol. Why buy GLA in a supplement when you make it yourself? Well, according to some proponents, your body doesn’t make enough of it, though no one knows how much is enough. It’s true that some diseases, such as cancer, multiple sclerosis, and diabetes, decrease the ability to convert linoleic acid into GLA, but that does not mean that GLA can be used to treat these diseases.
Knowledge versus claims
Science has not neglected evening primrose oil and the fatty acids it contains. A good deal is known about them, but the proposed benefits of the supplements are unproven. You’ll do well to ignore nearly all of the claims. One very small study did show some reduction in LDL ("bad") cholesterol, but there are better ways to accomplish this. A recent review of evidence by the American Board of Family Practice found that evening primrose oil has not been shown to be effective against diabetic neuropathy, despite the claims.
One common use for evening primrose and borage oil is for relieving the symptoms of rheumatoid arthritis—the kind that produces inflamed joints (as opposed to osteoarthritis, which is caused by wear and tear on the joints). There is some preliminary evidence that it may help, and the Arthritis Foundation considers it worth trying for rheumatoid arthritis. But you should talk to your doctor first. Fish oil supplements are another option.
Can’t hurt, might help?
Evening primrose oil appears to be safe. Stomach upset, headaches, and rashes have been reported as side effects. None of these are fatal, of course. But borage oil may contain liver toxins. Memorial Sloan-Kettering Cancer Center in New York warns against it as a cancer therapy, even in "normal" doses, unless it is certified free of these toxins, and lists it with chaparral and comfrey as known liver toxins.
And yet another problem: in today’s market, you don’t know what you’re getting. There’s no such thing as a standardized dose, and the supplements may not contain what the label states. Such supplements can also turn rancid. Prices vary, and depending on what kind you buy and how much you take, you could spend $15 to $50 a month on what we believe is a waste of money.
Add it all up: Evening primrose oil and similar products are unproven, and their manufacturers make troubling and often outrageous claims. Borage oil may be dangerous unless the toxins have been removed. And why buy supplements when you can so easily and cheaply get EFAs from a wide range of good foods?
UC Berkeley Wellness Letter, November 2003 |
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