I am often asked why I use evening primrose oil rather than borage oil as a source of gamma-linolenic acid, or GLA, in Udo's Choice Oil Blend. After all, borage oil is cheaper and contains more than twice as much GLA as evening primrose oil, so this would seem like the more logical choice. However, for me, the quantity of GLA in oil and its price are not primary deciding factors. Oil quality and the beneficial biological activity of its GLA should take priority. While borage oil is widely used in the marketplace as a source of GLA, my review of the research literature suggests evening primrose oil may be preferable.

Physical Structure of the Oils

The oils from evening primrose and borage act differently in the body because the oils themselves differ in several ways. Evening primrose contains far more omega-6 essential fatty acids and other beneficial 'minor ingredients' that play an important role in fat metabolism, especially that of GLA. In other words, GLA does not act alone in the body; it has help from other nutrients within the oil itself. For this reason, although both evening primrose and borage oil have been shown to improve some conditions such as high blood pressure, some research shows that evening primrose works better than borage, even though evening primrose actually contains less GLA.

What Does the Research Show?

Far more research has been done on evening primrose oil than borage oil. According to studies, the health-promoting activity of evening primrose is superior to borage in several ways:

• In humans, evening primrose reduces the production of TxB₂, a substance that increases blood's clotting tendency, making TxB₂ a risk factor for stroke, embolism, and heart attack. Borage oil, on the other hand, increases TxB₂, making clot formation leading to stroke, embolism, or heart attack more likely.

Evening primrose oil decreases human platelet stickiness (aggregation) of the blood, while borage oil increases platelet stickiness, making a blood clot in an artery more likely, thereby increasing risk of a stroke, heart attack, or embolism. In animals and humans, evening primrose elevates a substance in the body called DGLA, or dihomogamma-linolenic acid, from which the hormone prostaglandin E (PGE1) is made. PGE1 lowers cardiovascular risk factors, and DGLA also takes part in reactions that result in decreased inflammation.

• In mice, evening primrose oil increases production of hormones PGE₁ and prostacyclin I₂ (PGI₂₎; these two open up small blood vessels, increase blood supply to tissues, lower blood pressure, reduce inflammation pain and swelling, and reduce clot formation (platelet aggregation). In contrast, borage oil reduces PGI₂ levels dramatically, thereby lowering one of the body's main defenses against stroke or heart attack.

• In rats with high blood pressure, both types of oil lower blood pressure, but weight for weight, evening primrose oil is more effective.

• Evening primrose oil reverses diabetic nerve damage in rats; borage oil has little or no effect.

Toxicity of Evening Primrose and Borage

A search for toxicity of evening primrose came up with the following statements: ".appears to be safe for most people." ".has a very low toxicity." "Unrefined evening primrose oil contains no known toxins." "Unlikely to threaten life or cause significant symptoms."

Evening primrose oil has no known potentially toxic effects. Borage oil, in contrast, might contain traces of toxins always present in the borage plant and its seeds. As protection against being eaten, borage plants make natural toxins called pyrrolizidine alkaloids (PAs). Traces of PAs, found as 'minor ingredients' in borage seeds, might end up in borage oil. These toxic alkaloids accumulate in body tissues over time and can result in cancer, damage to the liver, kidney, gastrointestinal tract and respiratory system, and other serious problems.

Actual measurements of PAs have remained elusive for several reasons. First, any substance present below the detection limit of the test used cannot be measured. Second, few tests have been carried out, and fewer have been published. Third, although every batch of borage oil should be tested for PAs, manufacturers and distributors do not usually do this.

So, are pyrrolizidines present in borage oil? Consumers don't know. The presence of undetectable quantities is likely. One borage oil supplier has assured the public that pyrrolizidine alkaloids "have NEVER been found in borage seed oil." Aside from being untrue, because PAs have been found in borage oils, the statement implies absence of PAs, non-toxicity, and (therefore) safety for human consumption. However, several reputable sources, including the Canadian Pharmacy Journal and Tyler's Herbs of Choice: the Therapeutic Use of Phytomedicinals, have expressed concerns regarding the safety of borage oil.

Is Refined Any Better?

If unrefined borage oil contains traces of toxic PAs, refining borage oil largely removes them. Unfortunately, refined oil production requires treatment with NaOH (sodium hydroxide), then H₃PO₄ (phosphoric acid), then bleaching clays (which render oil rancid, imparting bad odor). To remove the bad odor (deodorize), oils are then heated up to 450�F (230�C). Both toxic and beneficial minor ingredients are removed from oils during deodorization.

This process used to make refined, bleached or deodorized oils changes some molecules from natural and beneficial to unnatural and toxic. In other words, unrefined borage oil may contain one kind of toxin, while refined borage oil contains other kinds of toxins.

Summary

Evening primrose and borage oils are not comparable. They are not mutually interchangeable. Their structural makeup is different. Research has shown differences in their chemistry and actions. Their potential for toxic effects is also different.

I take the cautions regarding borage oil seriously. There are unanswered questions regarding its safety. No one knows the cumulative effects of long-term use. This is why I prefer to err on the side of caution and don't use either unrefined or refined borage oil in any of my products. Instead, I choose expeller-pressed, unrefined evening primrose oil from organically grown seeds-which contains no PAs or toxins-for Udo's Choice Oil Blend.

Most unrefined oils contain beneficial oil-soluble 'minor ingredients' that come from the oil seeds, including vitamin E, carotene, phytosterols, lecithin, polyphenolic antioxidants, and many others. These minor ingredients are removed from oils by intensive processing to produce refined, bleached, deodorized, colorless, odorless, and tasteless oils. The minor ingredients in unrefined evening primrose oil are good for health and should remain in the oil.

The Fat Basics

Essential fatty acids (EFAs) are substances from fats that must be provided by foods because the body cannot make them, but must have them for health. EFAs exist in two families: omega-3s (also known as ALA, alpha-linolenic acid) and omega-6s (LA, or linoleic acid). From these two, the body makes several derivatives, hormones, and other active substances.

Omega-3 fatty acids include:

• ALA (alpha-linolenic acid; abundant in flax, and present in small quantities in hemp, walnut, soybean, and canola). Given enough ALA to start with, the body converts ALA into SDA, EPA, and DHA in various tissues, according to need;
• SDA (stearidonic acid; present in a few exotic seeds);
• EPA (eicosapentaenoic acid; used in hormone production; found in fish oils);
• DPA (docosapentaenoic acid);
• DHA (docosahexaenoic acid; the major brain omega-3; also found in the eyeball (retina), red-brown algae, and fish oils).

Omega-6 fatty acids include:

• LA (linoleic acid; abundant in safflower, sunflower, and corn; present in medium quantities in soybean, sesame, pumpkin seed, and almond; present in small quantities in canola, peanut, and olive). given enough LA to start with, the body converts LA into GLA, DGLA, and AA in various tissues, according to need;
• GLA (gamma-linolenic acid; present in evening primrose oil);
• DGLA (dihomogamma-linolenic acid; used in hormone production);
• AA (arachidonic acid; the major brain omega-6; used in hormone production; found in meat, eggs, and dairy products).