Study links fish and omega 3 fats to reduced risk of age-related macular degeneration in women

Fish and long chain omega 3 fats found in oily fish such as mackerel, salmon, trout and sardines have been previously linked to a reduced risk of age-related macular degeneration (AMD) and eyesight preservation.  Now a new large study in women (1) has found that regular consumption of fish and long chain omega 3 fats (EPA eicosapentaenoic acid and DHA docosahexaenoic acid) may protect against AMD.

It is still largely considered in the medical community that there is no recognised means of preventing against AMD other than through avoidance of cigarette smoking (1).  Any dietary prevention strategy would therefore be of public health significance since AMD is the most common cause of blindness in the UK in people aged over 50.

To recap from previous posts: The macular is the light sensitive area in the centre of the retina that controls visual field and the ability to see colours.  AMD is caused by the deterioration of the macular.  As this happens the peripheral, outer, vision remains intact as the centre field of vision becomes slowly blurry, grey or filled with a large black spot.  Two forms of AMD exists: the dry form which develops slowly, accounting for 90% of all cases; and the wet form which causes rapid deterioration of central vision.
The exact causes of AMD are unknown although free radical damage, where unstable oxygen molecules damage the eye cells, is strongly implicated.  Tobacco smoke and sun exposure can increase the level of free radicals in the body and both are a risk for AMD.  High blood pressure and diabetes are also risk factors as these conditions can limit blood flow to the eyes.

I have written about studies in the past which have linked diet and protection against AMD and also studies which show that fish and omega 3 fats might be protective, however data is considered to be limited at this stage.  This new study (1) adds to the evidence base and hopefully brings the value of nutrition into the medical foreground.

The study (1) involved looking at detailed food-frequency questionnaires for over 38000 female health professionals.  The women were free of an AMD diagnosis at the start of the study.  The women were then followed for about 10 years and any cases of AMD were noted.  235 cases of AMD were confirmed over the 10 years.  Women with the highest intake of the long chain omega 3 fatty acid DHA (compared to those with the lowest) had a significantly (38%) reduced risk of developing AMD, this was also the case for EPA intakes and fish consumption, women consuming 1 portion or more of fish a week compared to those consuming less than one portion per month had a (42%) reduced risk of AMD development

The authors conclude that “These prospective data from a large cohort of female health professionals without a diagnosis of AMD at baseline indicate that regular consumption of docosahexaenoic acid and eicosapentaenoic acid and fish was associated with a significantly decreased risk of incident AMD and may be of benefit in primary prevention of AMD”.

The study certainly adds to the weight of evidence suggesting that omega 3 fats and fish may be protective against AMD however the study only shows an association and does not prove that omega 3 fats can protect the eyes.  Further studies are necessary.  However, omega 3 fats have been shown in many studies to be vital for health and many individuals in the UK do not get enough of these fats from their diets.  Eating oily fish at least twice every week can help keep omega 3 levels high.  Many people choose to take an omega 3 fatty acid supplement daily in order to get a good supply of these fats.  It is advisable to check with your medical doctor prior to starting any new supplement regiment.

(1)Christen WG et al.  2011.  Dietary {omega}-3 Fatty Acid and Fish Intake and Incident Age-Related Macular Degeneration in Women. Arch Ophthalmol.  Published online March 14, 2011. doi:10.1001/archophthalmol.2011.34 

(2)Press release.  JAMA and Archives Journals (2011, March 14). Omega-3 fatty acid intake linked with reduced risk of age-related macular degeneration in women. ScienceDaily. Retrieved March 15, 2011, from http://www.sciencedaily.com­ /releases/2011/03/110314163439.htm

Written by Ani Richardson

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