CAN OMEGA-3 FATTY ACIDS SUPPORT HEALTHY EYES?

Dr. Hilary Jones | October 29, 2018

When it comes to everyday health there are copious amounts of information about many aspects of our health but as a medical Doctor it is evident that our eyes which are critical to the day-to-day running of our lives, health and wellbeing are comparatively overlooked.

The Royal National Institute of Blind People reports that every day in the UK 250 people start to lose their sight.  Furthermore, around two million people in the UK are living with sight problems that have a significant impact on their daily lives.1  The good news, however, is that at least half of all sight loss is preventable.1

ABOUT OMEGA-3S

Omega-3 fatty acids are also referred to as ‘essential fatty acids’ meaning that it is essential to consume these as the human body doesn’t produce them efficiently nor to the levels needed for human health. 2

The linchpin of the omega-3 family is alpha-linolenic acid (ALA) which yields eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).3  These fatty acids then produce signalling compounds known as ‘eicosanoids’ with anti-inflammatory properties. In contrast, the omega-6 family headed by linoleic acid (LA) yields arachidonic acid (ARA) and generates eicosanoids which trigger inflammation.3

Unfortunately whilst human beings once evolved on a diet abundant in fresh fish, seafood and algae with a balanced 1/1 ratio of omega-6 to omega-3 fatty acids modern Western diets now have a skewed ratio of up to 25/1 indicating that they provide copious amounts of omega-6 fatty acids and are deplete in omega-3 fatty acids.4

Latest data from the UK National Diet and Nutrition Survey5 also shows that adults are eating just 56 grams of oily fish a week; significantly lower than the advised weekly 140 grams.6 Omega-3 fatty acids including DHA are found predominantly in seafood, especially fatty fish and certain omega-3 supplements.7

OMEGA-3S AND HEALTHY EYES

Compared with other organs the eye has a particularly high DHA content.7 The retina (back layer of the eye) is concentrated with DHA and thought to optimise fluidity, retinal and visual function.8 Highly regarded meta-analytical evidence9 has shown that omega-3 fatty acids could be an effective therapy for conditions such as dry eye syndrome – when the eye doesn’t produce enough tears.

Age-related macular degeneration (AMD) which affects the central part of the retina called the macular is another major cause of reduced vision over the age of 50.10  Latest evidence has shown that EPA and DHA in doses between 5-7.5 g/day improved vision in AMD patients with mild to moderate visual impairment after 3-months - particularly those with dry AMD where retinal cells die off.10   

When it comes to eye health the European Food Safety Authority11 recognises the fact that DHA has an important structural role in the retina of the eye approving the claim that: “DHA contributes to the maintenance of normal vision”.  Officially to bear this claim, however, a food must contain 40 mg DHA per 100 grams and per 100 calories and indicates that the beneficial effect is obtained with an overall daily intake of 250 mg of DHA. 

A new Australian trial12 has shown that omega-3 supplementation (1000 mg EPA; 500 mg DHA; 900 mg ALA) could help to reduce intraocular pressure when taken daily over 3-months which could be used to help alleviate this in conditions such as glaucoma.

CONCLUDING REMARKS

Ocular (eye) health is central to our day-to-day running and quality of lives.  Modern lifestyle factors including close eye-screen distances and prolonged screen use may be further contributing to eye conditions such as ‘dry eye’ along with the fact that we are an ageing population.13

Giving our eyes a break - looking into the distance, stretching the head and neck, wearing sunglasses with a UV 400 and CE mark ensuring that they offer ultraviolet protection, giving up smoking and drinking in moderation can all go some way to protecting eye health along with regular eye tests.14,15

Alongside the recognised role of essential fatty acids especially DHA on maintenance of normal vision, this emerging evidence could be of particular benefit to those with dry eye syndrome or AMD.

Ongoing research is worthy in this important field of medicine.

References:

[1] Royal National Institute of Blind People (2018) Key information and statistics on sight loss in the UK. Available at: https://www.rnib.org.uk/professionals/knowledge-and-research-hub/key-information-and-statistics (accessed 2nd August 2018).

[2] Swanson D et al. (2012) Omega-3 fatty acids EPA and DHA: health benefits throughout life. Adv Nutr 3(1):1-7.

[3] Saini RK Keum YS (2018) Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism, and significance - A review. Life Sci 203:255-267.

[4] Simopoulos AP (2011) Evolutionary aspects of diet: the omega-6/omega-3 ratio and the brain. Mol Neurobiol 44(2):203-15.

[5] Food Standards Agency & Public Health England (2018) NDNS: results from years 7 and 8 (combined). Data extracted from Table 7.7. Available at:  https://www.gov.uk/government/statistics/ndns-results-from-years-7-and-8-combined (accessed 6th August 2018).

[6] Scientific Advisory Committee on Nutrition (2004) Advice on fish consumption: benefits & risks. London: TSO.

[7] Calder PC (2016) Docosahexaenoic Acid. Ann Nutr Metab.69 Suppl 1:7-21.

[8] Querques G et al. (2011) Retina and omega-3. J Nutr Metab 748361.

[9] Liu A Ji J (2014) Omega-3 essential fatty acids therapy for dry eye syndrome: a meta-analysis of randomized controlled studies. Med Sci Monit 20:1583-9.

[10] Georgiou T & Prokopiou E (2015) The New Era of Omega-3 Fatty Acids Supplementation: Therapeutic Effects on Dry Age-Related Macular Degeneration. J Stem Cells 10(3):205-15.

[11] European Commission (2018) EU Register on Nutrition and Health Claims. Available at: http://ec.europa.eu/food/safety/labelling_nutrition/claims/register/public/?event=search (accessed 6th August 2018).

[12] Downie LE Vingrys AJ (2018) Oral Omega-3 Supplementation Lowers Intraocular Pressure in Normotensive Adults. Transl Vis Sci Technol 7(3):1.

[13] Zhu Y et al. (2013) Analysis of risk factors for dry eye syndrome in visual display terminal workers. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 31(8):597-9.

[14] NHS Choices (2017) Healthy body: Eye safety. Available at: https://www.nhs.uk/live-well/healthy-body/eye-safety-at-home-and-work/ (accessed 6th August 2018).

[15] NHS Choices (2018) Healthy body: Look after your eyes.  Available at: https://www.nhs.uk/live-well/healthy-body/look-after-your-eyes/  (accessed 6th August 2018).

The information contained in Healthy Sights is for informational purposes only and should not be interpreted as medical advice, diagnosis or treatment. Content within this site was based off of recommendations in the United States. Consult your health care practitioner before changing your dietary regimen.

The information contained in Healthy Sights is for informational purposes only and should not be interpreted as medical advice, diagnosis or treatment. Content within this site was based on scientific information. Consult your health care practitioner before changing your dietary regimen.

© 2018 DSM

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