Oil of Evening Primrose (EPO) (OEP)

Scientific names: Oenothera biennis

Common names: Oil of Evening Primrose also is known as evening primrose.

Efficacy rating:

●●●...Positive clinical trials

Safety rating:

●...No safety concerns despite wide use.

What is Oil of Evening Primrose (EPO) (OEP)?

The evening primrose is a large, delicate wildflower native to North America and is not a true primrose. The blooms usually last only 1 evening. Primrose has yellow flowers, and the fruit is a dry pod that contains many small seeds. The small seeds contain an oil characterized by its high content of gamma-linolenic acid (GLA). Wild varieties of O. biennis contain highly variable amounts of linoleic acid and GLA. However, extensive cross-breeding has produced a commercial variety that consistently yields an oil with 72% cis-linoleic acid and 9% GLA. This perhaps is the richest plant source of GLA. A commercially grown mold has been reported to produce an oil containing 20% GLA, and newer strains may produce even greater yields.

The oil from evening primrose (OEP) seeds is cultivated in at least 15 countries and is available in more than 30 countries as a nutritional supplement or as a constituent in specialty foods.

What is Oil of Evening Primrose (EPO) (OEP) used for?

Overview

The oil obtained from the seeds of inbred strains of evening primrose is a rich natural source of essential fatty acids, especially cis-linoleic acid and GLA. The biologic importance of these fatty acids in maintaining normal physiologic function is well documented. Essential fatty acids (EFAs) are important as cellular structural elements and as precursors of prostaglandins. Prostaglandins help regulate metabolic functions. EFAs are the biologically active parts of polyunsaturated fats.

The use of GLA supplementation by the ingestion of OEP has been shown effective in a variety of medical disorders due to EFA deficiency or problems in EFA metabolism.

Cardiovascular disease

Ingestion of EFAs is believed to help reduce the incidence of cardiovascular disease and obesity. In some studies, GLA lowered plasma cholesterol and triglycerides. In a later report, there were no changes in patient's serum cholesterol, HCL cholesterol, or triglyceride levels. More research is needed to confirm benefits for these conditions.

PMS/Breast pain

OEP also may be useful in PMS and mastalgia (painful breasts). Clinical studies investigating OEP use in PMS have had positive results. OEP has been shown to help both cyclical and noncyclical mastalgia. OEP has not been shown to be helpful in the treatment of menopausal flushing.

Rheumatoid arthritis

OEP therapy for rheumatoid arthritis requires longer than 3 months for any beneficial effects. A study of OEP use resulted in a significant reduction in morning stiffness after 3 months. In another study, after 1 year of OEP treatment, patients had significantly reduced their use of NSAIDs.

Dermatological disorders

In atopic dermatitis, GLA was shown to be effective in improving skin condition, providing relief from pruritus, and allowing reduced reliance on cortisone medication. Women with premenstrual flare of eczema also reported improvement in their condition. OEP and fish oil also may be helpful for psoriasis.

Other uses

Some other illnesses that may be improved with the use of OEP include multiple sclerosis, autoimmune conditions, childhood hyperactivity, chronic inflammation, Sjogren's syndrome, ulcerative colitis, migraine headaches, and neurological conditions. Research is limited but promising in all these areas.

What is the dosage of Oil of Evening Primrose (EPO) (OEP)?

Evening primrose oil has been administered orally in clinical trials for arthritis, atopic dermatitis, PMS, and diabetic neuropathy at doses between 3 and 6 g/day. The typical content of gamma-linolenic acid is 8% to 10% in the oil.

As a nutritional supplement, the maximum label-recommended daily dose of OEP is approximately 4 g. This dose contains 300 to 360 mg GLA, which contributes:(1) 6 to 7 mg GLA/kg/day likely to be produced from linoleic acid in the normal adult female, (2) 23 to 65 mg GLA/kg/day consumed by a breastfed baby, or (3) 70 to 400 mg/kg/day of all the metabolites of linoleic acid consumed by a breastfed infant. According to these estimates, the amounts of GLA in the recommended doses of OEP are in the same range as the amounts of GLA and other related EFAs present in widely consumed foods.

EFAs cannot be manufactured by the body and must be provided by the diet in relatively large amounts. It has been recommended that 1% to 3% of total daily caloric intake should be in the form of EFAs. The World Health Organization recommends 5% for children and pregnant or lactating women.

Is Oil of Evening Primrose (EPO) (OEP) safe?

Contraindications

Contraindications have not yet been identified.

Pregnancy/nursing

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Side Effects

There have been no adverse effects attributed to oil of evening primrose.

Toxicities

No toxicity, carcinogenicity, or teratogenicity (physical defects in the fetus) has been reported.

References

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