Omega-3s Prevent Dry Eye by Acting on the Tear Glands
Dry Eye Syndrome: Fish Oil Can Prevent the Condition. Here’s How
A diet rich in Omega-3 EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) helps prevent symptoms of dry eye syndrome thanks to its action on the tear glands. The preventive effectiveness of Omega-3 can be further enhanced by adding Omega-6 GLA (gamma-linolenic 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 the journal Graefe's Archive for Clinical and Experimental Ophthalmology1.
Dry eye, a problem (not only) of contact lenses
Dry eye syndrome is a disorder associated with reduced tear production or alteration of their composition. Since the tear film primarily serves to keep the eye surface moist, the main consequence of this syndrome is corneal dehydration, the outermost layer of the eye. Main dry eye symptoms:
- sensation of having sand or a foreign body in the eye;
- redness;
- pain;
- burning;
- discomfort when exposed to light;
- ulcer formation (in more severe cases).
The problem is more frequent after age 40 and usually affects the following groups:
- contact lens users;
- people who spend a lot of time at the computer;
- those more exposed to sun and wind.
Omega-3 for eye health
Several studies have demonstrated the benefits of Omega-3 for the eyes: a diet rich in these nutrients helps, for example, to counteract the progression of retinitis pigmentosa, a disease that can lead to loss of vision2. Furthermore, these fatty acids are also useful in the treatment of retinopathy, a condition that can cause blindness in premature infants and in people with diabetes3. Finally, research from the University of Turku (Finland) showed that sea buckthorn oil, a plant rich in Omega-3, reduces symptoms of dry eye syndrome4. The French researchers focused on the role of a diet rich in Omega-3 or Omega-6 in reducing symptoms of this condition using rats as a model, in which the syndrome was induced through 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 food enriched with GLA, EPA, DHA, or all three fatty acids. The first effects of Omega-3 were visible just 2 days after syndrome induction: rats that had taken EPA and DHA showed a smaller reduction in the production of mucin contained in tears. Twenty-eight days after syndrome induction, fatty acid intake also reduced the appearance of corneal inflammation as well as the expression in the eye of molecules involved in the immune response. More detailed analyses revealed that the fatty acids introduced through diet localized at the tear glands. Here, EPA and DHA inhibited the production of molecules regulating inflammatory processes just 10 days after syndrome induction.
A direct action on the tear glands
Based on these results, the researchers concluded that EPA and DHA prevent dry eye symptoms by acting at the level of the tear 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 dry eye induced by scopolamine 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
