As I have a close friend who lost their sight from glaucoma, and am the proud owner of a retired guide dog, I’m acutely aware of the importance of caring for our eyes.
The older we get, the poorer our vision. But age is only part of the story – a healthy diet and lifestyle is a crucial factor, too. We can prevent eye problems by eating foods rich in vitamins, minerals and antioxidants.
The health of our eyes depends very much on an adequate blood supply. As the blood vessels are very small, even a tiny clot can block a vein in the retina, resulting in blurred vision or even blindness of the affected eye. When a neighbouring artery hardens, it can press on the vein. Such a retinal vein occlusion is more likely to happen in people who are overweight or obese, or have diabetes, high blood pressure or all of the above.
Unsurprisingly, the blood vessels of your eyes would benefit from diet and lifestyle changes that would apply for optimum heart health. We gave you our three top tips for a healthy heart last January. Click here to refresh your memory.
“Eat your carrots! They’re good for your eyes!”
If your grandmother said this to you, she wasn’t wrong! Our eyes are susceptible to free radical damage, which causes cataracts and macular degeneration. Free radicals are highly reactive molecules that can harm any kind of body cell. They are a side product of normal metabolic function, but our environment and our lifestyle add to them. Antioxidants, such as the vitamins A, C, and E, and the minerals zinc and selenium, are compounds that can disarm free radicals. We need variety. There are many different ones, some made within the body, others supplied by food.
Dietary antioxidants, especially flavonoids and carotenes, such as lutein, zeaxanthin and lycopene are particularly protective for the eyes. The macula, the area of the retina where images are focussed, has a high concentration of lutein and zeaxanthin. If the retina is unprotected, it changes. More and more metabolic waste products are deposited and form tiny “waste sacs”, called drusen – hallmark signs of macular degeneration to an ophthalmologist. The surface of the macula becomes uneven and blood circulation is impaired. This will be noticeable by the patient to whom objects will appear bent and contours distorted. This tiny area of the eye needs to be well nourished, because this is where lots of nutrients are required to guarantee good vision, and carotenoids are one of the most protective nutrients.
Studies have shown that optimum nutrition can reduce the risk of developing macular degeneration by up to 30%. Apart from zeaxanthin, lutein and other antioxidants, omega-3 fats are needed to support not only the macula, but also the vascular system of the eye.
The best source of omega-3 fats is oily fish, such as fresh tuna, salmon, mackerel, herring, sardines, pilchards and anchovies. Make sure to include 2-3 servings of fish per week into your diet. Good plant sources are milled flaxseeds, hemp seeds, pumpkin seeds and walnuts and their oils. However, the omega-3 fatty acids they contain have to be converted for our body to make full use of them, and conversion can be poor. If you are vegetarian or vegan or do not eat fish for any other reason, there is the option to supplement vegan EPA and DHA, as those long-chain fatty acids we need are called. We dedicated a blog post to omega-3 in May, click here to read it.
To get those eye healthy carotenoids, all you have to do is load up on fruit and vegetables, particularly yellow, orange and red ones. You can also find lutein and zeaxanthin in green leafy vegetables, such as kale, spinach, broccoli, peas and lettuce, and in egg yolks. Egg yolks are a better source compared to plants, because the high fat content in the yolk means that the carotenes – which are fat soluble – are better absorbed. Astaxanthin, another carotene, is what gives salmon its orange colour. The fish gets it from algae. You can enhance the absorption of carotenes from carrots, sweet potatoes, peppers, tomatoes and green leaves by having those foods with some oil or butter.
Zinc – another antioxidant – plays an essential role in the metabolism of the retina. Good sources of zinc are shellfish, particularly oysters, meat, eggs, dairy, beans and lentils, seeds, nuts, grains and dark chocolate. Vegetables are not great sources of zinc, but both white and sweet potatoes contain a decent amount.
The formation of free radicals is not completely avoidable, but we do have some influence on our exposure. Free radicals form in the process of combustion, for example when foods are cooked at a high temperature, i.e. fried, deep-fried or barbecued. More gentle cooking methods, such as steaming, steam-frying or slow-cooking produce fewer harmful substances.
Although antioxidants are available as nutritional supplements, studies consistently find that they are not as helpful as antioxidants from real food. As always, real food rocks!
For a referenced version of this blog, or more information on our services, please email lisa@vitalhealthnutrition.co.uk