Evening primrose (Oenothera biennia) -- while the name of this plant is enchanting, few of us can say that we have it growing in our gardens, or that we've ever even seen it.

In her book, Evening Primrose Oil, Judy Graham tells us that, for the most part, this plant grows wild along roadsides and does particularly well in places such as sand dunes. Despite its name, it is not a member of the primrose family, but belongs to the willow herb family. Graham tells us that it got its name because its yellow flowers are similar in color to real primroses; the "evening" part came about because these flowers open in the evening and quickly fade in bright sunlight. The first sources of this plant came from England.

While the evening primrose itself may be unknown to many, the benefits of evening primrose oil for a variety of health problems are renowned, particularly for women's health. Three of the most common complaints it has been known to relieve are premenstrual syndrome (PMS), fibrocystic breasts, and menopausal symptoms.

Gamma-linolenic acid

A discussion of the benefits of evening primrose oil would not be complete without mention of the polyunsaturated fatty acid gamma-linolenic acid (GLA), of which evening primrose oil is an excellent source (black currant seed and borage seed oils are two other good sources).

Lewis Harrison devotes a section of his book, Making Fats & Oils Work For You, to the benefits of gamma linolenic acid (specifically evening primrose oil). He says, "There is a `wonder substance' that, according to some experts, is likely to become extremely popular ... This substance is gamma linolenic acid.... GLA has been called the "wonder substance" because research has shown it to be beneficial in producing positive results with so many different ailments."

These benefits include: weight loss among people who are 10 percent or more over their ideal weight; lowering cholesterol and blood pressure; inhibiting the formation of blood clots; and helping to alleviate hypertension, arthritis, and dysmenorrhea (as well as the aforementioned women's health problems).

In a personal interview with Better Nutrition, Linda Page, N.D., Ph.D., author of Renewing Female Balance and How to be Your Own Herbal Pharmacist, explained GLA's and, thus, evening primrose oil's beneficial effects on women's health problems in particular.

She explained that because GLA is an early "precursor to prostaglandins [hormone-like substances produced in various tissues that mediate a range of physiological functions], and in the case of evening primrose oil, a prostaglandin balancer, it helps to regulate those fluctuating hormone levels."

It appears that GLA breaks down into di-homo-gamma-linolenic acid, which yields "series 1" (or "good") prostaglandins. If the quality of the oil has been compromised, GLA can break down to arachidonic acid (which itself is good) and oxygenases, which can produce series 2 prostaglandins and inflammation (which is bad); therefore, the quality (of the oil) must be superior. As we know, fluctuating hormones play a role in PMS, fibrocystic breasts, and menopausal symptoms, as well as many other conditions, so it makes sense that any substance that can help to balance this fluctuation has the potential to be beneficial.

GLA and weight loss. While weight loss and healthy weight maintenance is, and should be, a concern for all, it is usually of special concern to women. Page says, "People with GLA deficiencies produce more fat in their bodies. So, many overweight people, if they take evening primrose oil, will find that they will lose weight." She also notes that it can boost metabolism, helping overweight people to burn more calories.

Evening primrose oil: How much do I need?