Chances are, you’re well aware of the central role diet plays in maintaining heart and metabolic health.
You might not, though, connect what you eat with the health of your vision as you age.
Yet protecting your eyesight is essential for maintaining independence, supporting cognitive function and preserving quality of life.
And there’s strong evidence that diet plays an important role in keeping your eyes healthy.
Here’s why eye health deserves a place on your nutritional radar, plus the nutrients and foods that matter most.
How diet helps protect your eyes – and vision – over time
Our eyes are among the most metabolically active organs in the body.
The retina – a layer of cells at the back of the eye – is constantly converting light into nerve signals that the brain processes into vision.
Because it is continuously exposed to light and oxygen, the retina is especially vulnerable to oxidative stress, a process in which harmful free radicals outnumber the body’s protective antioxidants.
Oxidative stress can increase the risk of age-related eye diseases, including cataracts and macular degeneration.
From early to mid-adulthood, eating a healthy diet helps build up protective compounds in the eye that limit oxidative damage.
Improving diet later in life can benefit eye health, too, by slowing the progression of existing changes and preserving visual function for longer.
Cataracts and macular degeneration, explained
These two age-related eye diseases are among the leading causes of vision loss in Canadians over 55.
Cataracts – the clouding of the eye’s normally clear lens – develop when oxidative damage causes lens proteins to break down and gradually clump together.
Age-related macular degeneration (AMD) occurs when the macula – the central part of the retina responsible for fine, detailed vision – becomes damaged over time due to a mix of aging, oxidative stress, inflammation and genetic susceptibility.
The following key nutrients and dietary strategies can help support eye health as you age.
Lutein and zeaxanthin
These two carotenoids are concentrated in the macula, where they act as a filter, absorbing damaging blue light before it can reach light-detecting cells in the retina.
Lutein and zeaxanthin are strong antioxidants, neutralizing free radicals generated in the eye.
Higher intakes of these carotenoids are associated with a lower risk of advanced AMD and, to a lesser extent, certain types of cataracts.
Cooked leafy greens are exceptional sources of lutein and zeaxanthin – spinach, kale, Swiss chard, collards, dandelion greens and mustard greens. Other sources include winter squash, green peas, Brussels sprouts, broccoli and egg yolks.
Including a little fat in your meal will increase the body’s absorption of lutein and zeaxanthin.
Vitamin C
This powerful antioxidant is concentrated in the lens of the eye where it helps reduce oxidative damage.
Higher dietary intakes of vitamin C (about 150 to 300 mg per day) are associated with a 20-per-cent lower risk of developing cataracts.
Sweet bell peppers are an outstanding source of vitamin C; half of a raw large yellow, red and green pepper each supply, respectively, 170 mg, 105 mg and 66 mg of vitamin C. Broccoli (81 mg per cup raw), cauliflower (52 mg cup raw), Brussels sprouts (48 mg per half-cup cooked) and tomato juice (170 mg per cup) are also good sources.
You’ll also find plenty of vitamin C in strawberries (85 mg per cup), pineapple (80 mg per cup), citrus fruit (70 mg per one medium orange), kiwifruit (65 mg each) and mango (60 mg per cup).
Vitamin E
This fat-soluble antioxidant helps protect against cataract and AMD by neutralizing free radicals and stabilizing cell membranes in the lens and retina. It may also reduce inflammation in eye tissue.
Higher vitamin E intakes – at least 7 to 15 mg per day – are associated with a lower risk of cataract. Aim for 15 mg each day, the official daily recommended intake for adults.
Excellent sources include certain cooking oils, nuts, seeds and leafy green vegetables.
Per tablespoon, wheat germ oil contains 20 mg of vitamin E, sunflower oil has 6 mg, safflower oil delivers 4.5 mg, grapeseed oil provides 4 mg and olive oil has 2 mg.
Per one quarter-cup, sunflower seeds contain 12 mg, while almonds, hazelnuts and peanuts offer 9 mg, 5 mg and 3 mg, respectively. Cooked spinach and Swiss chard each provide 3.5 mg per cup.
Omega-3 fats
Studies have consistently tied higher intakes of omega-3s from fish (DHA and EPA) to a lower risk of developing AMD and, in people who have AMD, a lower risk of progressing to advanced disease.
Omega-3 fats, especially DHA, are highly concentrated in retinal cell membranes, keeping them fluid and flexible. Omega-3 fats also have anti-inflammatory effects in the eye.
The best sources are salmon, trout, sardines, herring, mackerel and albacore tuna.
Follow a Mediterranean-style diet
This healthy dietary pattern, rich in vegetables, fruit, whole grains, pulses, nuts, fish and olive oil, has been consistently linked to slower progression of AMD, especially to more advanced forms.
The Mediterranean diet provides fibre, omega-3 fats, antioxidants and anti-inflammatory phytochemicals which work together to support eye health.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.