Gamma Linolenic Acid Introduction

Gamma Linolenic Acid (GLA) is an omega-6 polyunsaturated fatty acid that is produced naturally in the body from the essential fatty acid linoleic acid. Gamma Linolenic Acid is also found in plant seed oils, including evening primrose, black currant seed, and borage oils. Gamma Linolenic Acid is a precursor to prostandins - hormone-like regulatory compounds that are involved in key body functions. Gamma Linolenic Acid may have anti-inflammatory, hypolipidemic, antithrombotic, and anticancer health benefits. [1-4]

Research suggests that Gamma Linolenic Acid may relieve inflammation by its conversion within the body, to anti-inflammatory metabolites; including series-1 prostaglandins, series-3 prostaglandins, and eicosopentaenoic acid (EPA). Gamma Linolenic Acid and associated metabolites, primarily found in cell walls and membranes, may provide for important anti-thrombogenic, anti-therogenic, and anti-inflammatory actions. [3-4]

Gamma Linolenic Acid can also be converted to arachidonic acid, a precursor to the series-2 prostaglandins. These compounds are often referenced as ‘bad’ prostaglandins, as they have been shown to promote inflammation and platelet aggregation. However, this ‘bad’ series-2 prostaglandin conversion is limited, compared to the ‘good’ series-1 and series-3 prostaglandin conversions. To obtain optimal series-1 and series-3 prostaglandin production, and it many associated health benefits, some experts recommend limiting dietary sources of arachidonic acid (primarily found in animal foods, saturated fat, hydrogenated oil products, and processed foods); while increasing the intake of beneficial fatty acids, such as Gamma Linolenic Acid. [1-2]

The best dietary sources of GLA include unrefined, organic, vegetable oils like those found in safflower, sunflower, and soy sources.

The best commercial, plant seed derived sources of Gamma Linolenic Acid, include; [1-2]

• Borage Oil - containing approximately 22 percent GLA
• Black Currant Seed Oil - contains 17 percent GLA
• Evening Primrose Oil - 9 percent GLA

Gamma Linolenic Acid is often employed for its anti-inflammatory benefits in conditions such as arthritis. Some studies suggest that Gamma Linolenic Acid supplementation may reduce some of the symptoms associated with arthritis. [5-7] One randomized, double-blind, placebo-controlled study found that treatment with 1.4 grams of Gamma Linolenic Acid derived from borage seed oil, effectively reduced the number of tender joints by 36%. A reduction in the number of swollen joints was also noted in 28% of the 37 rheumatoid arthritis patients studied. [6] Gamma Linolenic Acid may also be beneficial for other inflammatory disorders, such as Sjogren’s Syndrome. [4]

• Gamma Linolenic Acid may be used to support cardiovascular health by lowering serum lipids and blood pressure. Some studies suggest that Gamma Linolenic Acid may help to lower cholesterol and triglyceride levels and improve platelet dysfunction. [8-10]

• Gamma Linolenic Acid may yield certain anticancerous properties. Several preliminary studies have shown that Gamma Linolenic Acid may help to inhibit tumor cell growth, as well as helping to treat cerebral gliomas and pancreatic cancer. [11-15] More studies are needed to further establish Gamma Linolenic Acid’s efficacy regarding its purported anticancer effects.

• Gamma Linolenic Acid may be helpful as an aid for skin disorders, like atopic eczema. Clinical studies suggest that Gamma Linolenic Acid supplementation may reduce the symptoms of skin itching, inflammation, and chronic dryness. [16-22] One double-blind study found that treatment with 500 milligrams of borage oil improved symptoms in a subgroup of 160 eczema patients in a 24-week period. [19] However, this use remains largely unsubstantiated, as many study results are mixed. One major study showed that supplementation with evening primrose oil had no benefit in atopic dermatitis. [22]

• Gamma Linolenic Acid may be useful for the treatment of diabetic neuropathy. [23-24] One randomized, double-blind, placebo-controlled study found that treatment with 480 milligrams of Gamma Linolenic Acid improved symptoms in 111 diabetic neuropathy patients over a one-year period. [23]

• Gamma Linolenic Acid may also be useful for treatments of acute respiratory distress syndrome and premenstrual syndrome. Although more human studies are needed to determine this potential benefit. [25-26]

Standard Dosage: 500 -1,000 milligrams daily for prevention; and 1.4 grams daily for various therapeutic applications (e.g. rheumatoid arthritis).

Delivery Forms: Capsules, liquid oils. [1-4]

Gamma Linolenic Acid Deficiencies

Gamma Linolenic Acid deficiency may be due to an inability to convert linoleic acid to Gamma Linolenic Acid. Gamma Linolenic Acid deficiency may increase the risk for health conditions, including cardiovascular disease (e.g. high cholesterol and blood pressure), and allergic and inflammatory conditions (i.e. psoriasis, eczema, and arthritis). [1-2]

Gamma Linolenic Acid Toxicities

Gamma Linolenic Acid supplementation should be paralleled with vitamin E supplementation, to further protect against the potential free radical damage to Gamma Linolenic Acid itself.

Gamma Linolenic Acid should not be taken by hemophiliacs because of possible antithrombotic activity. It use is also contraindicated in pregnant and lactating women, as well as children. These individuals should not take supplemental Gamma Linolenic Acid unless recommended by a health care provider. It is recommended that GLA-containing products not be taken at least 14 days prior to any type of surgery or dental work. [2-4]

Due to its potential interactions, individuals should avoid combining Gamma Linolenic Acid with the following medications and nutritional supplements:

• Anticoagulant Medications (such as Warfarin)
• Bile acid sequestrants
• Lipase inhibitor supplements
• Orlistat
• Olestra
• Chitosan
• Mineral oil

Always inform your health care provider about the dietary supplements you are taking, as there may be potential for the development of side effects, nutrient and drug interactions, or allergy.

1. Murray MT. Encyclopedia of Nutritional Supplements, NY: Three Rivers Press, 1996: 247-256.

2. Pizzorno JE and Murray MT, eds. Encyclopedia of Natural Medicine, revised 2nd edition, CA: Prima Publishing, 1998: 50-51

3. Gamma Linolenic Acid (GLA), Dietary Supplement Information Bureau:

http://content.nhiondemand.com/dse/consumer/monoAll-style.asp?objID=100118&ctype=ds&mtyp=4

4. Gamma-Linolenic Acid (GLA), PDR Health:

http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/gam_0120.shtml

5. Belch JJ, Ansell D, Madhok R, et al. Effects of altering dietary essential fatty acids on requirements for non-steroidal anti-inflammatory drugs in patients with rheumatoid arthritis: a double-blind, placebo-controlled study. Ann Rheum Dis. 1988; 47:96-104.

6. Leventhal LJ, et al. Treatment of rheumatoid arthritis with gammalinolenic acid. Ann Intern Med. Nov1993;119(9):867-73.

7. Zurier RB, Rossett RG, Jacobson EW, et al. gamma-Linolenic acid treatment of rheumatoid arthritis. A randomized, placebo-controlled trial. Arthritis Rheum. 1996; 39: 1808-1817.

8. Ishikawa T, et al. Effects of gammalinolenic acid on plasma lipoproteins and apolipoproteins. Atherosclerosis. Feb1989;75(2-3):95-104.

9. Horrobin DF, Manku MS. How do polyunsaturated fatty acids lower plasma cholesterol levels? Lipids. Aug1983;18(8):558-62.

10. Chaintreuil J, Monnier L, Colette C, et al. Effects of dietary gamma-linolenate supplementation on serum lipids and platelet function in insulin-dependent diabetic patients. Hum Nutr: Clin Nutr. 1984; 38C:121-130.

11. Das UN, Prasad VV, Reddy DR. Local application of gamma-linolenic acid in the treatment of human gliomas. Cancer Lett. 1995; 94:147-155.

12. Hrelia S, Bordoni A, Biagi P, et al. gamma-Linoleic supplementation can affect cancer cell proliferation via modification of fatty acid composition. Biochem Biophys Res Commun. 1996; 14:441-447.

13. Das UN. Occlusion of infusion vessels on gamma-linolenic acid infusion. Prostaglandins Leukot Essent Fatty Acids. Jan2004;70(1):23-32.

14. Agombar A, Cooper AJ, Johnson CD. An aqueous formulation of gamma-linolenic acid with anti-proliferative action on human pancreatic cancer cell lines. Anticancer Drugs. Feb2004;15(2):157-60.

15. Karia C, Harwood JL, Morris AP, Heard CM. Simultaneous permeation of tamoxifen and gamma linolenic acid across excised human skin. Further evidence of the permeation of solvated complexes. Int J Pharm. Mar2004;271(1-2):305-9.

16. Manku MS, et al. Reduced levels of prostaglandin precursors in the blood of atopic patients: defective delta-6-desaturase function as a biochemical basis for atopy. Prostaglandins Leukot Med. Dec1982;9(6):615-28.

17. Horrobin DF. Essential fatty acid metabolism and its modification in atopic eczema. Am J Clin Nutr. Jan2000;71(1 Suppl):367S-72S.

18. Kerscher MJ, Korting HC. Treatment of atopic eczema with evening primrose oil: rationale and clinical results. Clin Investig. Feb1992;70(2):167-71.

19. Henz BM, Jablonska S, Van De Kerkhof PC, et al. Double-blind, multicentre analysis of the efficacy of borage oil in patients with atopic eczema. Br J Dermatol. 1999; 149:685-688.

20. Galli E, Picardo M, Chine L, et al. Analysis of polyunsaturated fatty acids in newborn sera: a screening tool for atopic dermatitis? Int Arch Allergy Appl. 1994; 82:422-423.

21. Morse PF, Horrobin DF, Manku MS, et al. Meta-analysis of placebo-controlled studies of the efficacy of gamma-linolenic acid in the treatment of atopic eczema. Br J Dermatol. 1989; 121:75-90.

22. Berth-Jones J, Graham-Brown RA. Placebo-controlled trial of essential fatty acid supplementation in atopic dermatitis. Lancet. 1993; 341:1557-1560.

23. Keen H, Payan J, Allawi J. Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group. Diabetes Care. 1993; 16:8-16.

24. Cameron NE, Cotter MA. Metabolic and vascular factors in the pathogenesis of diabetic neuropathy. Diabetes. Sep1997;46(Suppl 2):S31-7.

25. Gadek JE, De Michele SJ, Karlstad MD, et al. Effect of enteral feeding with eicosapentaenoic acid, gamma-linolenic acid, and antioxidants in patients with acute respiratory distress syndrome. Enteral nutrition in ARDS Study Group. Crit Care Med. 1999; 27:1409-1420.

26. Horrobin DF. The role of essential fatty acids and prostaglandins in the premenstrual syndrome. J Reprod Med. Jul1983;28(7):465-8.