For years, researchers have studied the role of the omega-3 fatty acids in supporting the human body's cardiovascular, reproductive, immune and nervous systems by helping to regulate biological functions.
Now, more research is starting to shed light on how the omega-3 fatty acids relate to visual health, with results indicating that these healthy fats may be incredibly important in terms of good vision and eye health.
If you’re keen to keep your eyes healthy for a long as you live, it’s important to brush up on the facts and to take a closer look at your current omega-3 intake.
The omega-3's and disease prevention
The omega-3 essential fatty acids are found in plant and marine life oils and regarded essential for overall health. Right now, scientists are particularly excited about two omega-3's that may play a key role in vision: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Studies have shown that the omega-3s may help reduce the risk of macular degeneration (MD), a debilitating eye condition that’s one of the biggest causes of blindness globally.
Apart from MD, omega-3 may also help protect against other eye diseases. For example, low levels of DHA and EPA have been associated with diabetic retinopathy, a condition that is responsible for approximately 5% of global blindness, according to the World Health Organisation.
In other studies, researchers have focused on various nutrients that may help heal other retinal conditions including glaucoma and cataract disease. Right now, there’s also growing evidence that nutritional deficiencies may be related to ocular surface disease and dry eye.
These findings are echoed by the American Optometric Association (AOA) that states a “number of studies in animals have shown that dietary deprivation of DHA results in visual impairment and retinal degradation, while dry eye syndrome has also been linked to omega-3 deficiency”.
How omega-3's promote eye health
When it comes to eye health and the different mechanisms involved, the omega-3s seem to work their magic as follows:
Age-related macular degeneration: The retina of the eye uses DHA to regenerate the outer section of the eye’s photoreceptors to process light. The retina also uses DHA to protect retinal pigment cells from damage.
Diabetic retinopathy: Studies show that a diet high in omega-3 reduces the formation of harmful new blood vessel growth, which sometimes occurs in more severe forms of this diabetes-related disease.
Glaucoma: Based on studies, people suffering with glaucoma tend to have low blood levels of DHA and EHA. These omega-3s can help adjust the microcirculation blood flow in the eye and the optic nerve.
Dry eye caused by wearing contact lenses: Nerves that help maintain a healthy eye surface in the cornea can be damaged or even destroyed by excessive or improper contact lens wear. The cornea is a clear dome-like structure on the front part of the eye where the contact lens lies. If these corneal nerves are damaged it can cause dry eye. DHA has been shown to reduce eye dryness and repair these nerves in the process.
Best sources of omega-3
So, it’s clear that a diet rich in the omega-3s is a pretty good investment in terms of your long-term eye health.
Try to incorporate foods that are rich in omega-3s wherever possible, bearing in mind the daily and weekly recommended allowances. The Australian Heart Foundation website offers these guidelines:
Good marine sources of omega-3 (DHA) are mostly found in oily fish such as Atlantic and Australian salmon, blue-eye trevalla, blue mackerel, gemfish, canned sardines, anchovies, canned salmon, trout, herring and some varieties of canned tuna. Other fish such as barramundi, bream or flathead, and seafood such as arrow squid, scallops and mussels, are also good sources of omega-3.
Animal sources such as free-range eggs, chicken and beef may also contain DPA, along with smaller quantities of EPA.
Many plant foods contain alpha-linolenic acid (ALA), another type of omega-3. This is found mainly in fats and oils (for example, canola oil, perilla and soybean oil) as well as in linseeds (flaxseeds), chia seeds and walnuts.
Other food sources of omega-3 include dark green leafy vegetables such as spinach, spirulina, raw sprouted radish seeds, dried tarragon and fresh basil.
Consuming at least 90mg (for women) and 160mg (for males) of omega-3 (marine source) every day is adequate for good health, suggests the Australian National Health and Medical Research Council (NHMRC).
Reach your weekly omega-3 target by eating a serving of canned salmon or sardines, and another serving of oily fish or seafood (either caught or bought). Fish is very versatile as it can be prepared in many ways, including eating it raw in sushi, steamed, grilled, lightly pan-fried, baked or barbequed. You can also add the fish to stir-fries, casseroles, salads, pasta and soup.
If you don’t like fish or are a vegetarian, use flaxseed oil or other plant sources to ensure you get your weekly allowance of omega-3.
Alternatively, the NHMRC suggests adding omega-3 supplements, which are usually derived from either microalgae or oily fish. Read supplement labels carefully or consult your local pharmacist or health professional to identify products that contain the correct levels of omega-3s.
“Look for supplements with the highest EPA and DHA content. Many 1,000mg capsules contain 180mg of EPA and 120mg of DHA, giving a total marine omega-3 content of 300mg,” says the NHMRC. “Therefore, to reach the 500mg every day, you may need to have one or two capsules to supplement your dietary intake.”