Dietary Antioxidants and Other Nutrients
The following are the dietary antioxidants and other valuable nutrients you need for good eye health, that is, the ones you should receive through the foods you eat and from the nutritional supplements you take.
Vitamin A and Beta-carotene
Vitamin A helps maintain night vision by forming rhodopsin, or retinal purple, the pigment essential to night vision. It is fat-soluble and can build up in the liver, resulting in toxicity.
To avoid this, use beta-carotene instead, which is a water-soluble precursor to Vitamin A. Your body can turn beta-carotene into Vitamin A whenever it needs to.
As a bonus, beta-carotene is an excellent dietary antioxidant, helping reduce the effects of free radical attacks.
Please note, however, that beta-carotene may lead to increased incidence of lung cancer among smokers and ex-smokers who recently quit.
Vitamin C is a very important dietary antioxidant.
Vitamin C content in the aqueous humor is 30 to 50 times the level found in blood. In the lens of the eye, it is higher than anywhere else in the body except the adrenal glands. In a lens with a cataract, there is almost no Vitamin C present.
Vitamin C is very important in treating glaucoma. It helps collagen integrity, and it lowers inner eye pressure. People with glaucoma need very large amounts of Vitamin C, anywhere from 2,000 mg to 35,000 mg per day.
Vitamin E is probably the most potent of the dietary antioxidants. It is found in very high concentrations in the eyes. It is a chain-breaking antioxidant, and is an important scavenger of free radicals.
Selenium content in a lens with a cataract is about 15% of normal levels. The antioxidant enzyme glutathione peroxidase is selenium-dependent, and thus is far lower in the cataractous lens.
Selenium works synergistically with Vitamin E. Together they are more effective at fighting free radical damage than either alone would be.
Zinc concentrations in the eyes are higher than in any other part of the body, and they are especially high in the retina. Here zinc is essential for oxidation and metabolism.
Zinc also makes it possible for the liver to release Vitamin A, which is used to make rhodopsin. Low zinc levels can prevent the photoreceptors from functioning.
Zinc is also essential to the activity of dozens of enzymes, including the antioxidant enzymes involved in protecting the lens from cataracts and the macula from macular degeneration.
Zinc binds with copper, and is then excreted through the digestive system, so copper must be supplemented along with zinc.
Copper works with Vitamin C to fight oxidative stress, and it is necessary for proper enzyme functioning.
Too little copper can cause serious problems, such as anemia, hypothermia, and mental deterioration. Too much copper can also cause serious illness, including hepatitis, cirrhosis, and renal dysfunction.
Since copper binds with zinc, any zinc supplementation requires copper supplementation as well.
Manganese is an important dietary antioxidant as it also activates the antioxidant enzymes.
Taurine is the most abundant amino acid in the eyes. It helps move sodium and potassium and so helps prevent or reverse the effects of cataracts. Low levels of taurine are associated with degeneration of the retina.
Most people, including vegans, can make taurine from cysteine and Vitamin B6, so supplementation for eye health is probably not necessary. Levels up to 6 grams per day are used for heart health, and will benefit the eyes as well.
Lutein and Zeaxanthin
Lutein and zeaxanthin are carotenoids found in very high concentrations in the retina, and also in the lens of the eye. They are the xanthophyll pigments that give the macula its yellow color.
These two dietary antioxidants absorb visible light rays (particularly blue light) that cause macular degeneration damage. Their presence has also been found to help prevent cataract formation.
Lycopene is a red carotenoid dietary antioxidant that is helpful in slowing the effects of macular degeneration.
Lycopene is found in red-fleshed fruits, including tomatoes, red grapefruit, guava and watermelon. Its absorption in the body improves when ingested with a good quality oil, such as olive oil.
Bilberry and Other Flavonoids
Flavonoids (also known as bioflavonoids) are the pigments that give fruits their colors. Anthocyanins are flavonoids that strengthen and tighten capillaries, ensuring continuing blood flow to all parts of the eye.
Tight capillaries can also help reduce wet macular degeneration, which is caused when abnormal blood vessels start to grow and leak.
Flavonoids are essential for proper absorption and use of Vitamin C.
They also help in maintaining collagen, which is the main component of the lens and is the connective tissue that supports the eye. Thus, flavonoids are important in maintaining clear lenses and in keeping intraocular pressure low.
Flavonoids are also dietary antioxidants, with properties that reduce incidence of cataracts and macular degeneration by stopping free-radical damage.
Ginkgo biloba improves blood flow to all body parts, and so is important in good eye health.
It can slow retinal deterioration. It is also a dietary antioxidant, and can slow down the aging process caused by free radicals. It prevents destruction of the retinal neurons and ganglion cells, which helps protect the optic nerve from the damage caused by glaucoma.
Quercetin, a flavonoid found in garlic and onions, as well as in red wine, may play a part in reducing the chance of contracting glaucoma.
It is one of a group of chemicals that relaxes the filter on the eye’s drain, allowing more fluid to drain, which reduces pressure buildup.
Co-enzyme Q10 is a naturally occurring substance found in most foods. It helps in oxidative metabolism by interacting with specific enzymes to improve their biochemical functions.
Co-enzyme Q10 improves the use of oxygen at the cellular level, so it can be helpful in the eyes, where vast amounts of oxygen are used.
Omega-3 Fatty Acids
Omega-3 fatty acids are essential fatty acids (EFAs), that is, they are necessary for proper functioning bodily function. They are carriers of Vitamins A, D, E and K, all of them fat-soluble vitamins.
Omega-3 fatty acids, along with omega-6 fatty acids, are taken into the membranes of your cells. These membranes are responsible for nutrient transport, so if you ensure a balance of these oils, the membranes are much more flexible and can carry more nutrients.
Not enough omega-3 fatty acid in your diet (and/or too much omega-6 fatty acid) can lead to hardening of the arteries, which can raise blood pressure and affect your vision.
EFAs also help maintain the myelin sheath around nerves, and thus help protect the optic nerve from damage.
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are two omega-3 fatty acids that are part of fish oils. They can be obtained by eating salmon, albacore tuna, mackerel or sardines. Take at least 100 IU of Vitamin E to help assimilate the oils.
Evening primrose oil, black currant oil, and borage oil all provide gamma-linolenic acid (GLA), which is an anti-inflammatory fatty acid.