Evening Primrose Oil

Townsend Letter for Doctors and Patients,  Jan, 2001  by Tori Hudson

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(Oenothera biennis L.)

History

The evening primrose plant has been commonly known as tree primrose and sundrop. Evening primrose can be found in many parts of North America and are native in the northern temperate zone, especially at high altitudes. Only six or eight species of the 500 species of Primula are found in North America. They are mostly perennial herbs, flower in the spring and come in numerous colors but commonly, white and purple. The native people of North America as well as the English and pilgrims, were well aware of the healing properties of the leaves and bark as an astringent, nervine and sedative. It was often used for stomach and liver complaints, coughs and female disorders. Even the roots were eaten as a vegetable. The seeds were recommended as a coffee substitute in wartime and have a strong flavor similar to poppy seed oil. The therapeutic value of the seed oil is a more recent discovery. It is this seed oil, and its essential fatty acid content that holds the most interest today in maintaining health and preventi ng disease.

Understanding essential fatty acids

Quality oils and fats are actually essential in maintaining our health and in the prevention of certain chronic diseases. Our bodies need a healthy ratio of saturated, monounsaturated and polyunsaturated fats. Some polyunsaturated fats are as essential as vitamins and minerals for the maintenance of good health -- these are the essential fatty acids (EFAs), or good fats.

We know we don't get enough EFAs which play crucial roles in the body on a minute-by-minute basis. They produce hormone-like compounds; maintain cell membrane function; regulate pain, inflammation and swelling; dilate and constrict blood vessels; mediate immune response; regulate smooth muscle responses; prevent blood clots; regulate blood pressure and nerve transmission; regulate cholesterol levels; and even more.

Our bodies cannot make EFAs -- they must be obtained from the diet or through supplementation. That is why they are called "essential fatty acids." Under ideal conditions, the body uses linoleic acid (LA) to produce GLA (gamma linolenic acid-a polyunsaturated cis fatty acid). Likewise, the body uses alpha linolenic acid (ALA) to produce eicosapentenoic acid (EPA). In turn, GLA and EPA are used to produce beneficial hormone-like compounds called prostaglandins. Specifically, GLA is used to produce series one prostaglandins such as prostaglandin E1 (PGE1) while EPA is used to produce prostaglandin E3 (PGE3).

Prostaglandins affect the function of virtually every system in the body. These molecules are used in the regulation of inflammation, pain, blood pressure, fluid balance, blood clotting, and affect hormone production and function. In order to maintain a proper balance of the anti-spasmodic and anti-inflammatory prostaglandins (PGE1 and PGE3) with the pro-spasmodic and pro-inflammatory prostaglandins (PGE2), it is critical to have the proper amount of each fatty acid, particularly LA, GLA, ALA and EPA. The body has to receive a constant supply of EFAs and a balanced supply of each fatty acid in order to produce the right prostaglandins as they are needed. Without adequate amounts of GLA and EPA, prostaglandin production will be reduced, and problems will result.

Evening Primrose Oil is an omega-6 rich oil, containing both LA and GLA. It is by far the most popular and familiar source of GLA. Evening Primrose Oil contains 74% LA, 11% oleic acid, 6% palmitic acid, 2% stearic acid, and 9% GLA which is present in only a few other plant seeds.

The key to understanding the important need for supplementing with oils rich in GLA, such as evening primrose oil, is that many of us cannot convert LA to GLA efficiently. Dietary deficiencies, disease conditions, processed oils, trans-fatty acids, heated oils, alcohol, aging, viral infections and sugar consumption block, slow down, or interfere with the enzyme that catalyzes the conversion of LA to GLA.

Clinical Uses

Health problems supported and/or suggested by scientific trials using evening primrose oil include premenstrual syndrome, fibrocystic breast pain, eczema, sunburn, rheumatoid arthritis, diabetes, heart disease, osteoporosis and ulcerative colitis. Other conditions for which it may provide benefit include menopause and pregnancy.

Premenstrual syndrome

PMS has been linked to excessive and incorrect prostaglandin production. Specifically, women with PMS may have a deficiency of PGE1, at the central nervous system [1] and in other tissue such as breast tissue. Supplementing with EFAs may raise the body's production of PGE1. The most popular and scientifically documented method is to supplement with GLA in the form of evening primrose oil in order to increase production of PGE1. Rigorous scientific studies have demonstrated that supplementing with EPO has a significant effect on symptoms of PMS. [2-4] The effects of EPO have been shown to improve all symptoms including premenstrual headaches, depression, irritability, and bloating. EPO also dramatically relieves premenstrual breast pain and tenderness. Oils that contain high quantities of GLA include evening primrose oil, borage oil and black currant oil.