Your eyesight is probably the most important of your five senses.
Eye health goes hand-in-hand with general health, but there are a few nutrients that are especially important for the eyes.
These nutrients help maintain eye function, protect the eyes against harmful light and reduce the development of age-related degenerative diseases. This article lists the main nutrients that will maximize your eye health, their dietary sources and potential benefits.
1. Vitamin A
Vitamin A deficiency is one of the most common causes of blindness in the world.
This vitamin is essential for maintaining the eyes' light-sensing cells, also known as photoreceptors.
If you don't consume enough vitamin A, you may experience night blindness, dry eyes or more serious eye diseases, depending on how severe your deficiency is. Vitamin A is only found in animal-derived foods. The richest dietary sources include liver, eggyolks and dairy products.
However, you can also get vitamin A from antioxidant plant compounds called provitamin A carotenoids, found in high amounts in some fruits and vegetables. Provitamin A carotenoids provide around 30% of people's vitamin A requirements, on average. The most efficient of them is beta-carotene, which is found in high amounts in kale, spinach and carrots.
2–3. Lutein and Zeaxanthin
Lutein and zeaxanthin are yellow carotenoid antioxidants known as macular pigments.
This is because they are concentrated in the macula, the central part of the retina. The retina is a layer of light-sensitive cells on the back wall of the eyeball. Lutein and zeaxanthin act as a natural sunblock. They're thought to play a central role in protecting the eyes against harmful blue light.
Controlled studies show that the intake of lutein and zeaxanthin is proportional to their levels in the retina. One observational study in middle-aged and elderly people showed that consuming 6 mg of lutein and/or zeaxanthin per day significantly reduced the risk of age-related macular degeneration.
The researchers also discovered that those with the highest intake of lutein and zeaxanthin had a 43% lower risk of macular degeneration, compared to those with the lowest intake.
On the other hand, other observational studies suggest that lutein and zeaxanthin may also reduce the risk of cataracts. Lutein and zeaxanthin are usually found together in foods. Leafy greens are not the only good sources of these carotenoids. Egg yolks, sweet corn and red grapes may also be high in lutein and zeaxanthin.
4. Omega-3 Fatty Acids
The long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are important for eye health.
DHA is found in high amounts in the retina, where it may help maintain eye function. It is also important for brain and eye development during infancy. For this reason, DHA deficiency can impair vision, especially in children.
Evidence also shows that taking omega-3 supplements may benefit those with dry eye disease. Dry eye disease occurs when the eyes don't form enough tear fluid. This causes the eyes to become excessively dry, leading to discomfort and visual problems.
One study in people with dry eyes showed that taking EPA and DHA supplements daily for three months significantly reduced dry eye symptoms by increasing the formation of tear fluid.
Omega-3 fatty acids may also help prevent other eye diseases. A study in middle-aged and elderly people with diabetes found that taking at least 500 mg of long-chain omega-3 fatty acids daily may reduce the risk of diabetic retinopathy.
In contrast, omega-3 fatty acids are not an effective treatment for age-related macular degeneration. The best dietary source of EPA and DHA is oily fish. Additionally, omega-3 supplements derived from fish or microalgae are widely available.
5. Vitamin C
The eyes require high amounts of antioxidants — more so than many other organs. The antioxidant vitamin C appears to be especially important, although controlled studies on its role in eye health are lacking.
The concentration of vitamin C is higher in the aqueous humor of the eye than in any other body fluid. The aqueous humor is the liquid that fills the outermost part of the eye.
The levels of vitamin C in the aqueous humor are directly proportional to its dietary intake. In other words, you can increase its concentration by taking supplements or eating foods rich in vitamin C.
Observational studies show that people with cataracts tend to have a low antioxidant status. They've also found that people who take vitamin C supplements are less likely to get cataracts.
Vitamin C appears to play a protective role in the eyes, but it is unclear if vitamin C supplements provide added benefits for those who aren't deficient.
High amounts of vitamin C are found in many fruits and vegetables, including bell peppers, citrus fruits, guavas, kale and broccoli.
This post originally appeared on Healthline.