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Copyright © 2017 Natural Medicines (www.naturalmedicines.com)
August 2013

Gamma Linolenic Acid and Omega-3 Studied For Dry Eye

Gamma-linolenic acid (GLA) and omega-3 fatty acids may benefit people who suffer from chronic dry eye, according to a study.

GLA is a dietary omega-6 fatty acid found in many plant oil extracts. Commercial products are typically made from seed extracts from evening primrose, black currant, borage oil, and fungal oil. GLA is not found in high levels in the diet. It has been suggested that some people may not be able to efficiently convert the omega-6 fatty acid linoleic acid to GLA. Supplementing with GLA-containing oils may help increase GLA levels in the body. GLA is available commonly as a dietary supplement and is sold over the counter in capsules or oil to treat many conditions, including eczema, high cholesterol, depression, and chronic fatigue syndrome.

The main essential fatty acids in the human diet are omega-3 and omega-6 fatty acids. Foods that provide omega-3 fatty acids include fish oil and certain plant and nut oils. Fish oil contains two omega-3 fatty acids called docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Some nuts, seeds, and vegetable oils contain alpha-linolenic acid (ALA), which may be converted to DHA and EPA in the body. Omega-3 fatty acids are thought to provide a wide range of health benefits, including a lower risk of coronary heart disease and improvement in cholesterol. There have also been promising results from studies looking at omega-3 for cancer, depression, and attention-deficit hyperactivity disorder (ADHD). Due to these potential health benefits, fish oil, which is rich in omega-3 fatty acids, has become a popular supplement.

In the current study, the researchers looked at the effects of a supplement containing both GLA and omega-3 fatty acids on chronic dry eye. They set out to determine whether this supplement might help prevent the production of compounds that have been implicated in dry eye development.

The research team enrolled 38 postmenopausal women who had tear dysfunction. The subjects were randomly assigned to receive the supplement containing GLA and omega-3 fatty acids or to a placebo for six months. The researchers collected information on the participants' eye health at the beginning of the study, at four weeks, 12 weeks, and 24 weeks. They used the Ocular Surface Disease Index score to detect any changes.

The results suggested that the supplement significantly improved the Ocular Surface Disease Index score compared to placebo. People who received the supplement reported improvement in eye irritation, and the researchers noted better corneal smoothness in this group. However, effects were lacking on other measures of eye health, such as tear production and tear breakup time.

The authors concluded that supplementing with GLA and omega-3 fatty acids for six months may help relieve chronic dry eye symptom in postmenopausal women. More research is needed to confirm and better understand these findings.

For more information about GLA or omega-3 fatty acids, please visit Natural Standard's Foods, Herbs & Supplements Database.

References

  1. Natural Standard: The Authority on Integrative Medicine. 
  2. Sheppard JD Jr, Singh R, McClellan AJ, 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 Jul 23. [Epub ahead of print] 

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