Evening primrose oil

What is it?

Evening primrose oil is made from the seeds of Oenothera biennis or evening primrose. This plant is a tall biennial that is native to North America. Evening primrose oil is rich in a substance called gamma-linolenic acid (GLA), which contributes to many important functions in the body. GLA is normally created during the breakdown of omega-6 fatty acids inside the body. Omega-3 and omega-6 fatty acids are essential fatty acids. They are called essential because they must be included in the diet since our body can’t make them. In theory, chronic viral infections, such as HIV, may impair the body’s ability to convert omega-6 fatty acids into GLA. Evening primrose oil may, therefore, be useful to ensure adequate levels of GLA in the body. It may have other uses as well.

What do people with HIV use this supplement for?

To help heal nerve damage (peripheral neuropathy)
Peripheral neuropathy (PN) is a burning or tingling in the hands and feet. It is associated with the use of the anti-HIV drugs ddI, d4T and ddC. PN also occurs in people with diabetes. Several trials have shown that evening primrose oil can help relieve the symptoms of diabetic PN. In one study, 22 people who took four grams of evening primrose oil daily for six months had a significant improvement in symptoms. Evening primrose oil appears to be more effective for this purpose than other oils containing GLA such as borage or black currant oil. Evening primrose oil has not been studied as a treatment for peripheral neuropathy in people with HIV. Nevertheless, nutritionists like Lark Lands recommend GLA supplements in combination with B-complex vitamins, vitamin E and omega-3 fatty acid supplements for PHAs suffering from neuropathy.

To treat skin conditions associated with anti-HIV drugs
Some anti-HIV drugs can cause dry skin and itching, symptoms most commonly associated with indinavir (Crixivan). Electronic forums such as PI-treat and Crix-list contain anecdotal reports that describe improvements in these symptoms with the use of evening primrose oil. According to such anecdotes, two grams a day is generally recommended. Evening primrose oil is also used to treat eczema and dermatitis in HIV-negative people. Although some studies have not shown an improvement, an analysis of nine different trials showed that evening primrose oil significantly improved dermatitis. The improvements continued over time and were greater when higher doses were used. Evening primrose oil was, however, less successful at relieving the itch caused by this condition.

To cope with premenstrual syndrome
Compared with women not infected with HIV, many HIV-positive women have heavier periods and more intense symptoms of premenstrual syndrome, such as pain and bloating. Evening primrose oil is commonly used in Britain to treat these symptoms. Naturopaths generally suggest four to six months of use in order for symptoms to improve.

To reduce cholesterol levels
In recent years, many PHAs have experienced elevated levels of cholesterol that may be linked to the use of anti-HIV drugs, particularly protease inhibitors. Evening primrose has helped decrease cholesterol in HIV-negative people. One British study using three to four grams of evening primrose oil for 12 weeks showed significant benefit. Both men and women participated in the study. The treatment was most effective in those participants with the most abnormal cholesterol levels. In the subjects with the highest cholesterol levels at the start of the study, total cholesterol levels decreased by 30 per cent. The potential of evening primrose oil to reduce cholesterol levels in PHAs taking protease inhibitors has not been studied.

Available forms and usage

Evening primrose oil is usually sold in capsules or as a liquid. It should contain a minimum of eight per cent gamma-linolenic acid. PHAs usually take two grams a day with food, divided into several doses. People experiencing peripheral neuropathy may take doses as high as four grams. To prevent the oxidation of evening primrose oil, at least 400 IU/day of vitamin E should also be taken with meals. Evening primrose oil is now widely available and can be purchased from herbalists or from health food or drug stores.

Cautions and concerns

Evening primrose oil is generally considered quite safe. Rare adverse effects include nausea, headache and diarrhea.

Evening primrose oil may have an effect on the immune system but these results have been inconclusive and sometimes contradictory. Some nutritionists recommend that PHAs take evening primrose oil (omega-6) in combination with an omega-3 fatty acid like flaxseed oil in order to balance their intake of essential fatty acids.

Evening primrose should not be taken by people with mental illness who experience mania because it may make this condition worse. Itshould also be taken cautiously by epileptics or other people who experience seizures because it has been associated with an increased frequency of seizures in a few case.

Evening primrose oil should be used cautiously by people taking drugs that reduce blood clotting, such as aspirin. In theory, evening primrose oil may be less effective in people taking beta-blockers, which are drugs used to treat high blood pressure.

References

Boon H, Smith M. The Botanical Pharmacy. Kingston: Quarry Health Books, 1999.

Horrobin DF, Manku MS. How do polyunsaturated fatty acids lower plasma cholesterol levels. Lipids 1983;18:558-62.

Lands, Lark. Nutrient therapy for neuropathy, 1999.

Morse PF, Horrobin DF et al. Meta-analysis of placebo-controlled studies of the efficacy of Epogram on the treatment of atopic eczema. British Journal of Dermatology 1989;121:75-90.

Nemecz G. Evening Primrose. US Pharmacist 1998 Nov.

Puolakka J, Makarainen L et al. Biochemical and clinical effects of treating the premenstrual syndrome with prostaglandin synthesis precursors. Journal of Reproductive Medicine 1985 Mar;30(3):149-53.