Eye Chat – From a Retinal Surgeon’s Perspective
Previously, I had talked about nutritional supplements for age related macular degeneration (AMD) and further research is now ongoing to look at the benefits of omega 3 fatty acids as well as lutein and zeaxanthin in a large clinical trial known as AREDS 2 (Age Related Eye Diseases Study).
These polyunsaturated fats are essential nutrients as they cannot be synthesized in our body. The omega 3 fatty acids are made up of short chain alpha-linolenic acid and the long chain docosahexanoic acid (DHA) and eicosapentanoic acid (EPA). Examples of foods rich in omega 3 fatty acids are fish, shellfish, flaxseed, walnuts and soy bean.
Importance to the retina?
The brain and eye are highly enriched with omega 3 fatty acids which accumulate in these tissues during early neonatal life. DHA is a major structural lipid in the retina particularly the disc membranes of the photoreceptor outer segments. The photoreceptors are very metabolically active as they are responsible for converting light energy into electrical impulses to be transmitted to the brain for interpretation of images. Consequently, a steady supply of DHA is required for normal retinal function. The complete function of omega 3 fatty acids in the retina is still not fully understood but it is postulated that they have other neuroprotective and anti-angiogenic effects.
Omega 3 and Omega 6 fatty acids imbalance
Humans evolved on a diet with a 1:1 ratio of omega 6:omega 3 but in the industrialized countries nowadays, our diets are more like 12:1 or even 18:1! This hugely disproportionate intake of omega 6 fatty acids has been contributory in the observed increased incidence of heart disease, cancer and other inflammatory disorders. Basically, omega 6 fatty acids exert pro-inflammatory effects whereas omega 3 fatty acids exert anti-inflammatory effects but both are required by our body (in proportionate amounts) for normal functioning.
Omega 3 and AMD
Age Related Macular Degeneration is the leading cause of blindness in developed nations and intense research into the treatment and prevention of this disease has led to observational studies showing evidence supporting the association between omega 3 fatty acids and AMD. A high intake of individual fatty acids such as linoleic acid and a high cholesterol intake could lead to an increased risk of AMD. In contrast, epidemiological studies have shown that an increased intake of omega 3 fatty acids could have a protective role especially in wet AMD.
Historically, low incidences of AMD have been reported in Japan and Iceland where fish consumption is high but in recent times, more and more of this disease have been seen in these countries which could reflect a change in the dietary behavior towards a more “western diet”.
Striking a Balance – Making a Difference
It is therefore, very important to have the correct balance of omega 6 and omega 3 fatty acids in our diet. In our current food environment, it is very difficult to get away from the omega 6 overload as almost all our food is cooked with sunflower oil or corn oil or other vegetable oils and all these are laden with omega 6. A lot of food manufacturers of health foods in specialty stores will also coat their products with vegetable oil to improve the texture and taste and unwitting consumers who believe they are taking the healthy option, are in fact tipping the scales towards the omega 6 imbalance.
We are currently victims of modern society and of our lifestyles. Knowing that a lot of these “lifestyle diseases” such as high blood pressure, diabetes, heart disease, etc can be prevented with modified behaviour and habits, we should make an effort to change our ways. For some more information on how to “tip the balance in your favour” visit my blog on www.lec.com.my/youcare-eyecare.
For more information about this topic or other eye health subjects, please visit my blog at: www.lec.com.my/youcare-eyecare. Or call Lee Eye Centre : 05-254 0095.