Omega-3s prevent dry eye by acting on tear glands

Dry eye syndrome: fish oil can prevent the condition. Here's how

A diet rich in the Omega-3s EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) helps prevent the symptoms of dry eye syndrome through their action on the lacrimal glands. The preventive effectiveness of Omega-3 can also be increased by addingOmega-6 GLA (gamma-linoleic acid) to the diet. Researchers at the Institut National de la Recherche Agronomique (INRA) in Dijon, France, demonstrated this through experiments conducted on rats, published in Graefe's Archive for Clinical and Experimental ^{Ophthalmology1} journal.

Dry eye, a problem (not only) of contact lenses

Dry eye sy ndrome is a disorder associated with reduced tear production or altered tear composition. Since the tear film serves primarily to keep the ocular surface moist, the main consequence of this syndrome is dehydration of the cornea, the outermost layer of the eye. Main symptoms of dry eye:

• Feeling of having sand or a foreign body in the eye;
• redness;
• pain;
• burning;
• discomfort during exposure to light;
• Ulcer formation (in severe cases).

The problem is most common after the age of 40 and usually affects the following:

• Contact lens wearers;
• Who spends a lot of time on the computer;
• Who is more exposed to the sun and wind.

Omega-3 for eye health

Several research studies have demonstrated the benefits of Omega-3s for the eyes: a diet rich in these nutrients helps, for example, to counter the progression of retinitis pigmentosa, a disease that can lead to ^vision loss2. Not only that, these fatty acids are also useful in treating retinopathy, a condition that can cause blindness in children born prematurely and in those with ^diabetes3. Finally, research from the University of Turku (Finland) has shown thatsea buckthorn oil, an Omega-3-rich plant, reduces symptoms of ^dry eye syndrome4. French researchers focused on the role of a diet rich in Omega-3 or Omega-6 in reducing the symptoms of this condition using rats as a model, in which the syndrome was induced with appropriate experimental techniques.

2 months of Omega-3 to counteract dry eye

Before inducing the condition, the researchers fed the animals for 2 months with a feed enriched in GLA, EPA, DHA, or all 3 fatty acids. The first effects of the omega-3s were visible as early as 2 days after induction of the syndrome: less reduction in the production of mucin in tears was observed in rats that had taken EPA and DHA. Twenty-eight days after induction of the condition, intake of the fatty acids had also reduced the occurrence of corneal inflammation as well as the eye-wide expression of molecules involved in the immune response. More detailed analyses found that dietary intake of fatty acids went to the level of the lacrimal glands. Here EPA and DHA went to inhibit the production of molecules that regulate inflammatory processes as early as 10 days after induction of the syndrome.

A direct action to the lacrimal glands.

Based on these results, the researchers concluded that EPA and DHA prevent dry eye symptoms by acting at the level of the lacrimal glands.  

Source 

1. Viau S, Maire MA, Pasquis B, Grégoire S, Acar N, Bron AM, Bretillon L, Creuzot-Garcher CP, Joffre C, "Efficacy of a 2-month dietary supplementation with polyunsaturated fatty acids in scopolamine-induced dry eye in a rat model," Graefes Arch Clin Exp Ophthalmol. 2009 Aug;247(8):1039-50. Epub 2009 May 5 

2. Berson EL, Rosner B, Sandberg MA, Weigel-DiFranco C, Willet WC, "Omega-3 Intake and Visual Acuity in Patients With Retinitis Pigmentosa Receiving Vitamin A," Arch Ophthalmol., Published online ahead of print, doi:10.1001/archopthalmol.2011.2580 

3. Sapieha P, Stahl A, Chen J, Seaward MR, Willett KL, Krah NM, Dennison RJ, Connor KM, Aderman CM, Liclican E, Carughi A, Perelman D, Kanaoka Y, Sangiovanni JP, Gronert K, Smith LE, "5-Lipoxygenase metabolite 4-HDHA is a mediator of the antiangiogenic effect of ω-3 polyunsaturated fatty acids," Sci Transl Med. 2011 Feb 9;3(69):69ra12 

4. Larmo PS, Järvinen RL, Setälä NL, Yang B, Viitanen MH, Engblom JR, Tahvonen RL, Kallio HP, "Oral sea buckthorn oil attenuates tear film osmolarity and symptoms in individuals with dry eye," J Nutr. 2010 Aug;140(8):1462-8. Epub 2010 Jun 16