Evening primrose oil
Evening primrose oil is a dietary supplement derived from the seeds of the evening primrose plant, Oenothera biennis . Its Latin name is derived from the Greek word for wine, reflecting the folk belief that the plant could relieve the symptoms of a hangover. Other names for the plant are tree primrose and sundrop. Native Americans used the leaves and bark of evening primrose as a sedative and astringent; it was given for stomach and liver complaints as well as disorders of the female reproductive system. More recently, the discovery of antioxidant and other properties of the seed oil has focused attention on its usefulness in treating a range of diseases and disorders, including as an anti-inflammatory, and for premenstrual syndrome (PMS), rheumatoid arthritis, diabetes, osteoporosis, ulcerative colitis, menopausal problems, and heart disease.
Evening primrose oil is given by contemporary naturopaths and other alternative practitioners to relieve the discomfort of symptoms associated with PMS, eczema, sunburn, fibrocystic breast disease, arthritis, and diabetes. It is also given to lower the risk of preeclampsia and eclampsia in pregnancy and osteoporosis in older women.
Evening primrose oil is obtained from the seeds of the plant by pressing. The oil can be taken directly as a liquid or in the form of capsules.
Evening primrose oil is considered a useful dietary supplement because it is a good source of essential fatty acids (EFAs), Omega 6 predominantly. EFAs are called essential fatty acids because the human body cannot produce them; they must be obtained from the diet. EFAs maintain the function of cell membranes, regulate pain and inflammation, prevent blood clots, regulate blood pressure and cholesterol levels, and help to produce hormone-like substances known as prostaglandins. Prostaglandins function as inflammation mediators in the short-term regulation of glands and other body organs. It is thought that evening primrose oil relieves the symptoms of PMS by preferentially stimulating anti-inflammatory prostaglandins.
Under normal conditions, the body uses an EFA called linoleic acid to produce a compound called gamma linoleic acid, or GLA. Evening primrose oil contains both linoleic acid (74%) and GLA (9%), making it the most familiar and popular source of GLA. The other compounds contained in evening primrose oil are oleic acid (11%) and palmitic acid (6%).
Evening primrose oil can be obtained in health food stores in either liquid or capsule form. Consumers are advised to look for that which is organic and cold-pressed (not oxidized by heating), and to store it in the refrigerator. Standard dosage varies according to the condition being treated. The dosage for breast pain from fibrocystic disease is 3 g per day. For sunburn, patients may take up to 8 capsules daily until the symptoms subside. Dosages for eczema and rheumatoid arthritis depend on the concentration of GLA in the preparation of evening primrose oil, and should be decided in consultation with a physician, or naturopathic practitioner.
Evening primrose oil can also be used as a topical preparation to treat sunburn and eczema. One recipe for a homemade topical preparation calls for mixing one part of diced plant with four parts of heated petroleum jelly. The mixture is stored in a tightly closed container and refrigerated, as well.
All parts of the evening primrose plant are safe to eat. The roots can be boiled and eaten like parsnips. The seeds were roasted and used as a coffee substitute when food rationing was in effect during World War II.
Evening primrose oil should not be given to patients with epilepsy, and only after a consultation with a physician should it be given to children.
Evening primrose oil has not been reported as having toxic or severe side effects. Some patients, however, have reported nausea, headache, and softening of the stools.
Reports of side effects from using evening primrose oil in topical preparations for sunburn and other skin problems are the same as with any EFA supplement. Bruising due to damage of the blood platelet function is possible.
Experts in pharmacology advise against using evening primrose oil with phenytoin (Dilantin) and other anticonvulsant medications, as the oil may lower the threshold for seizures . No other significant drug interactions have been reported.
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Rebecca J. Frey, Ph.D.