Omega 3 is one of many fatty acids which are essential building blocks of cell membranes important for the brain and nervous system. Omega 3 also has potent anti-inflammatory capabilities.
Omega 3 is what is called an unsaturated fat. Unsaturated fats are generally derived from vegetables and fish, and are liquid at room temperature. (Saturated fats tend to be solid at room temperature and are usually found in animal fat and dairy products, like cheese and butter.) While there are many fatty acids, the most important dietary omega-3 fatty acids are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is termed an “essential” nutrient meaning it must be ingested, because we cannot make it in our bodies. EPA and DHA can be formed from ALA.
Dietary Sources of Omega 3
Omega 3 can be found in the forms of EPA and DHA in cold water fish such as salmon, sardines, tilapia, swordfish, halibut, pollock, shellfish, and tiny shrimp called krill.
Vegetable sources of omega 3 are in the form of ALA (alpha-linolenic acid). ALA is found in seeds like flax seeds and pumpkin seeds, and nuts like walnuts, pecans, and hazelnuts. The body uses the ALA to transform it into EPA and DHA.
Omega 3 Fatty Acids and the Eye
The Omega 3 fatty acids have been studied extensively in regard to their role in cardiovascular health and neurological development. From these studies researchers have noted improvement in blood vessel and neurological health. DHA is found in high concentrations in the retina. The implications for the eye are that the tiny blood vessels of the retina remain healthy to provide adequate circulation to the neural tissues. It is also thought to help maintain the integrity of the retinal nerves themselves. Recent studies indicate a benefit to diabetics by reducing the risk for diabetic retinopathy. (Medline)
Along with its anti-inflammatory capabilities it is thought to reduce the risk for age-related macular degeneration (AMD).
There is another bonus for eye health with an adequate omega 3 fatty acid intake: doctors have long recommended to their dry eye patients that they supplement omega 3 fatty acids to reduce inflammation and promote healthy eyelid glands that produce moisture. Studies have shown improvement in dry eye symptoms for those who increase their omega 3 fatty acid intake.
Omega 3 Fatty Acid Dosages
Studies of AMD and omega 3 are inconclusive as to daily dosages. It is recommended that 1000 mg ( 1 gram) fish oil capsules per day is beneficial for cardiovascular health and dry eye therapy.
For those with fish allergies or for those who are vegans, flaxseed and flax oil are a source of the ALA form of omega 3 and there are commercially available DHA sources derived from yeast and microalgae.
There have been many studies on the benefits of omega 3 fatty acids for cardiovascular, brain, eye, and joint health. When trying to decide on their benefits, you may find that studies are contradictory to one another. Studies do differ by whether it is DHA and EPA supplements or if it is omega 3 fatty acids ingested by dietary fish and fish oils.