Herbal & Plant

Evening Primrose & Starflower Oil

What about evening primrose and starflower (borage) oils?

Evening primrose oil and its relative, starflower oil, are very popular supplements in the UK and are used for a variety of health benefits including skin conditions, such as eczema, and joint conditions such as arthritis and alongside fish oil to aid brain function in children. Its most common indication however is to benefit hormonal balance, particularly in regard to pre-menstrual syndrome (PMS).

What do evening primrose and starflower oils contain?

Evening primrose and starflower oils are very rich sources of a type of omega-6 fatty acid called gamma linolenic acid or GLA. GLA can be made in our bodies from another fatty acid called linoleic acid which is a major component of common oils such as sunflower and corn oil. However, studies indicate that the efficiency of this conversion is very poor and so many nutritionists believe that optimum levels can only be achieved with supplementation.

What does GLA do?

GLA is a precursor to an important hormone like chemical in the body called prostaglandin (PGE1). This works in a complex way in the body but it plays a role in moderately dampening the inflammatory response. 
This is why GLA rich oils have been advocated for conditions where inflammation is a key mediator of symptoms such as eczema and other types of dermatitis, and also of arthritis.

What is the evidence of effect of evening primrose and starflower oils?

Eczema and arthritis
Initial trials of evening primrose oil with eczema or atopic dermatis and arthritis appeared positive with reduction in symptoms being demonstated. However, other more recent trials have tended to fail to reproduce these effects and many authorities now believe that the benefits of evening primrose oil may be quite modest and furthermore, the intakes necessary for these benefits are high. Typically scientific studies of eczema have used between 3-6 grams of EPO per day which is the same as taking 3-6 large 1000mg capsules of evening primrose oil per day, whilst those for arthritis have typically used about 14g of EPO or 14 large capsules per day.  
Overall, there has been a recent shift of opinion with many nutritionists with the recognition that more consistent benefits are seen with omega-3 supplementation for the above conditions compared with GLA containing oils such as evening primrose. 
Women suffering from PMS have been found to exhibit different blood fatty acid profiles with low levels of GLA being a common observation. This has lead to the suggested use of GLA containing oils for the relief of PMS.
However, trials undertaken to prove this effect have been disappointing with very little eveidence of any meaningful effect of supplementation with EPO. If any effects are to be seen it seems most likely to be expressed in reduction of breast pain.  Overall however, the conclusion of a review of the evidence for effect of GLA containing oils in PMS was that it was of little value in management of symptoms of PMS.
Again, the levels of GLA use are normaly quite high and for extended periods before any effects which may be present are actually felt. As such the opinion of the SC expert panel is that evening primrose and other GLA containing oils may be worth considering if other nutritional support strategies fail to bring adequate relief. However, delivery of the expected benefit of PMS symptoms may be inconsistent, and will require a minimum of 240mg GLA per day for a minimum of 12 weeks.

Is there any difference in evening primrose and starflower oils?

The only difference is that starflower (borage) oil contains about twice as much GLA as evening primrose oil and so the concentration of GLA in capsules is greater, meaning that fewer capsules are needed to provide the minimum level of 240mg GLA.

How much evening primrose or starflower oil do I need to take per day?

The minimum level of GLA required to provide a chance of delivering intended benefits is 240mg per day. This is typically equivalent to about 2-3 x 1000mg capsules of EPO and 1-2 x 1000mg capsules for starflower oil.