A healthy diet, with a broad range of nutrients, can help to prevent the development of some eye conditions. A recent survey found sixty per cent of people living in the UK had no idea that what they eat can affect the health of their eyes.
As most people know, eating the right foods in the right amounts and exercising regularly, can help maintain a healthy weight. Being overweight in itself does not seem to be a risk factor for any particular eye condition but some of the health complications of being overweight can cause problems that can affect your sight.
This blog outlines some of the ways healthy eating can support healthy eyes.
Being overweight is a significant risk factor for developing type 2 diabetes and diabetes can affect your eyes in a number of ways.
Changing levels of blood sugar can cause your vision to become temporarily blurry and in the longer term, this can cause cataracts to develop earlier.
Another complication of diabetes is retinopathy, which causes damage to the tiny blood vessels in the retina. Sometimes this can also lead to macular oedema.
The macula gives us the detailed vision we rely on for activities such as reading and recognising faces. Macular oedema can cause problems with your sight including distortion or a blank patch in the middle of your vision and can make activities such as reading difficult. Changes to the blood vessels at the back of the eye due to diabetes can also for some people cause significant sight loss.
Having a healthy diet and losing weight helps to reduce your risk of developing diabetes. If you are already diagnosed, monitoring your diet and weight, as well as controlling your blood glucose levels, blood pressure, cholesterol and triglyceride levels will help to prevent you developing complications of diabetes including those which can affect your sight.
Age-related macular degeneration (AMD)
In AMD, the cells of your macula, the central part of the retina, stop working, causing a deterioration of central vision. This is the sight we use for detailed tasks such as reading and recognising faces.
It is thought over your lifetime, free radicals, highly reactive substances created in your body by breathing, eating and by other factors such as air pollution and smoking tobacco, cause damage to the cells in your body.
Antioxidants are thought to help delay or prevent free radicals from damaging your cells. Lutein and zeaxanthin are carotenoids found in the retina, and dietary intake of these compounds has been shown to have antioxidant properties and to improve pigment density in the macula. This pigment protects the cells in the macular area by absorbing excess blue and ultraviolet light and neutralizing free radicals. Lutein and zeaxanthin are usually found together in food.
You’ll find lutein and zeaxanthin in most fruits and vegetables, especially yellow and orange varieties and leafy greens. Egg yolks are an even richer source of these nutrients.
Two recent large scale studies carried out in America called the Age Related Eye Disease Studies (AREDS and AREDS2) explored the role of these antioxidants in slowing down the progression of AMD in people already diagnosed with the condition. AREDS and AREDS2 found that for some people with AMD, taking an antioxidant formula did slow down the progression of their condition. See the RNIB’s nutritional supplements for AMD page for more information about this. Always consult your Optometrist or GP before taking supplements.
Dry eye is a common condition where there may be a problem with your tears that usually keep your eyes comfortable and moist. Clinical trials have shown that omega 3, a group of fatty acids that we get from our diets, can have a positive effect on the symptoms of dry eye when taken in certain quantities.
Cold water fish like salmon, tuna, sardines and mackerel are excellent sources of EPA and DHA, the important omega-3 fatty acids. The NHS recommends that we eat at least two portions of oily fish a week. If you do not eat fish you can also get omega-3 by eating flaxseed/linseed or rapeseed oils as well as walnuts and eggs enriched with omega-3.
Taking omega 3 supplements have also been found to help with the symptoms of dry eye in some trials. However, as with all supplements these may not be suitable for everyone and if you are thinking of taking omega 3 supplements for dry eye it would be important to discuss this with your GP or ophthalmologist (eye specialist) before starting.
Retinal vessel occlusion
A retinal vessel occlusion is a blockage in the blood vessels of your eye that can cause sight loss. Having high blood pressure, high cholesterol levels, being diabetic, smoking and being overweight can all increase the risk of atherosclerosis and of having a retinal vessel occlusion. These factors can also increase your risk of stroke, which can for some people also cause problems with vision.
Having a healthy diet, low in saturated fat, losing weight and taking regular exercise as well as stopping smoking and reducing the amount of alcohol you drink can help to prevent or reverse the process of atherosclerosis, reducing your risk of retinal vessel occlusion and stroke.
Some research has shown that a healthy diet that includes colourful fruits, vegetables and whole grains could decrease the risk of cataracts. Antioxidant vitamins and phytochemicals found in fruits and vegetables that may reduce the risk of cataracts include vitamins A, C and E, lutein and zeaxanthin.
Consumption of fish, which is high in omega-3 fatty acids, has also been linked to potentially reduced risk of cataracts or their progression.
In summary, good nutrition at all ages is vital for good health, and plays an important role in maintaining healthy eyes. As you think about ways to improve your eye health, remember that vitamins and nutritional supplements are not a cure for eye disease. Always talk to your optometrist about any concerns you may have about your eye health.
 Eyecare Trust Healthy Eyes, Report