Written by Jessica Patella, ND. A combination of omega-3 and omega-6 oil improved symptoms of dry eye, smoothness of the cornea and decreased eye discomfort.
An estimated 5 million Americans over the age of 50 suffer from dry eye (4). Dry eye (keratoconjunctivitis sicca) occurs when the body cannot properly produce tears to lubricate the eye or when the surface of the eye becomes inflamed or irritated (1-3). Because omega-3 fatty acids and omega-6 fatty acids are anti-inflammatory, they were used in a study to determine if supplementation might help chronic dry eye (1).
The study included 38 participants with chronic dry eye, (average age of 61 +/- 1 years), who were randomly divided into either the placebo group (n=19) or the treatment group (n=19). The treatment group took 2 softgels twice daily that contained a combination of omega-3 and omega-6 fatty acids from fish oil and black currant seed oil (omega-3s: alpha linolenic acid (ALA) 196.0 mg, EPA (eicosapentaenoic acid) 126.0 mg,DHA (docosahexaenoic acid) 99.0 mg; omega-6s: linoleic acid 710.0 mg, gamma linoleic acid (GLA) 240.0 mg, all per 4 softgels). Sunflower oil was used in the placebo softgels because it contained less than 0.1% of omega-6 oils and undetectable levels of omega-3 oils (1).
After supplementation daily for 6 months, the Ocular Surface Disease Index score improved significantly with supplementation compared to placebo (21 +/- 4 vs. 34 +/- 5, p=0.05). The Ocular Surface Disease Index is a measurement of the severity of eye discomfort; the results indicated that eye discomfort decreased with supplementation of omega-3 and omega-6 oils (1).
The surface asymmetry index was significantly lower in the supplement group compared to placebo (0.37 +/- 0.03 vs. 0.51 +/- 0.03, p =0.005) at 6 months. The surface asymmetry index is a measurement of the smoothness of the cornea of the eye and the level of asymmetry increases with dry eye. Supplementation with omega-3 and omega-6 oils lowered the surface asymmetry index, indicating improvement (1).
The placebo group had significantly increased HLA-DR* intensity by 36% +/- 9% and CD11c** by 34% +/- 7% when compared to the supplement group (p=0.001 for both) at 6 months. HLA-DR and CD11c stains observe specific cells in the conjunctiva of the eye, both which increase with dry eye. During the 6 months, both values increased significantly in the placebo group, indicating progression of the dry eye in the placebo group (1).
Neither group had any effect on tear production, tear breakup time or corneal or conjunctival staining (1). This indicated that omega oil supplementation improved signs and symptoms mainly by decreasing inflammation in the eye, not by increasing tear production.
In conclusion, fish oil and black currant seed oil, a combination of omega-3 and omega-6 oils improved signs and symptoms of dry eye (1). The researchers suggested the supplement should be considered in the treatment of dry eye (1).
*A cell surface receptor involved in disease resistance.
** A chain membrane protein involved in cell activation
Source: Sheppard Jr, John D., et al. “Long-term supplementation with n-6 and n-3 PUFAs improves moderate-to-severe keratoconjunctivitis sicca: a randomized double-blind clinical trial.” Cornea 32.10 (2013): 1297-1304.
© 2013 by Lippincott Williams & Wilkins.
Posted September 16, 2013.
Jessica Patella, ND, is a naturopathic physician specializing in nutrition and homeopathic medicine and offers a holistic approach to health. She earned her ND from Southwest College of Naturopathic Medicine in Tempe, AZ, and is a member of the North Carolina Association of Naturopathic Physicians. Visit her website at www.awarenesswellness.com.
References:
- Sheppard JD, et al. Long-term Supplementation With n-6 and n-3 PUFAs Improves Moderate-to-Severe Keratoconjunctivitis Sicca: A Randomized Double-Blind Clinical Trial. Cornea. 2013, pre-publication.
- Stern ME, et al. The pathology of dry eye: the interaction between the ocular surface and lacrimal glands. Cornea. 1998;17:584–589.
- Pflugfelder SC. Antiinflammatory therapy for dry eye. Am J Ophthalmol. 2004;137:337–342.
- Facts About Dry Eye. National Eye Institute.
