Nutrition and eye health - 2015 Update

 

The food you eat really can affect your eye health.  There are specific antioxidants and other nutrients that have been shown to be important in good eye health.

A free radical is an unstable atom, molecule or ion that has an electron missing.  Because of the missing electron the  free radical can easily attach itself to other  atoms,  molecules or ions in a process called oxidation.  Radiation, heat, electrical discharge, electrolysis, and chemical reactions can all create free radicals. The free radicals disrupt the orderly structure of the cells.  In most cases a free radical leads to a chain of free radicals and a chain of chemical reactions.

The chemical reactions that take place during cellular metabolism creates many free radicals. The chemical reactions that take place in the retina, and especially in the macula during the process of vision create more free radicals then most other areas of the body, except the brain.

The disorganization of the cellular structure by these free radicals results in cellular changes which affect cellular function. In the macula these cellular changes are often seen as changes in the retinal pigment epithelium, which are then seen as pigmentary changes in the macula.  Instead of a  homogenous pigmentary appearance there are areas of hyperpigmentation and hypopigmentation.

 

 

As the macular cellular function becomes more disorganized retinal receptor waste products accumulate near the retinal receptor instead of being transported away as in normal function.  These waste products are called drusen.  They appear as a small white spots in the macular area.  In early dry age-related macular degeneration the drusen appear as hard discrete spots.   In later wet age-related macular degeneration the drusen appear more soft and fluffy.

 

 

In wet age-related macular degeneration the cellular disturbance reaches a point where there is insufficient oxygen for normal cell function.  In response to this hypoxia (lack of oxygen), new blood vessels known as neovascularization grow into the macula.  These blood vessels are very fragile and often hemorrhage leading to further macular damage and can eventually result in a macularscar.

 

 

The only treatment available to treat or help prevent "Dry" Age-related macular degeneration is antioxidants.  Antioxidants can neutralize the free radicals present and slowdown the further destruction of the cells.  They will not reverse pre-existing damage.  Vitamins A, C and E, beta-carotene, lutein and zeaxanthin have antioxidant properties.

Smoking

Age Related Macular Degeneration is 6 times more common in smokers than non-smokers and we really are not sure why, but it may be related to an increase in free radicals created by smoking.

Vitamin A

Vitamin A is used to create the pigments in the retina that are involved in the visual process. Is also important for healthy immune system.  Good sources of vitamin A are milk, eggs, Fortified cereals, dark colored orange or green vegetables such as carrots, sweet potatoes, pumpkin, oranges cantaloupes, apricots and peaches.  Excess vitamin A can cause dizziness, nausea, vomiting, headaches, blurred vision and loss of muscular control.   Smokers, ex-smokers or asbestos workers that take Vitamin A supplements have a 28% increase of lung cancer and should not take vitamin A.

Vitamin C (Ascorbic acid)

Vitamin C helps the body of the iron and calcium.  It also aids in wound healing and contributes to brain function.  Good sources of vitamin C are citrus fruits, red and green bell peppers, tomatoes and spinach, broccoli, cantaloupe and potatoes. Excess vitamin C can lead to dry skin, jaundice, fever, back pain. dizziness, vomiting, headache and facial flushing.

Vitamin E

Vitamin E is important for the immune system.  It also is important for red blood cell formation.  Good sources of vitamin E are The soils, such as sunflower and safflower, nuts, seeds and green leafy vegetables.  Excess vitamin E can act as an anticoagulant and lead to bleeding.

Lutein and zeaxanthin

These are carotenoids which are yellow, orange and red pigments synthesized only by plants.  Good sources of Lutein and zeaxanthin are dark green, leafy vegetables such as kale, broccoli, asparagus, and spinach.

Zinc

Zinc is an essential trace mineral that is highly concentrated in the retinas.  It plays an important role in transporting Vitamin A from the liver to the retina. A zinc deficiency results in poor night vision.  Good sources for zinc are oysters, red meat, poultry, seafood fortified cereals, beans, nuts whole grains and dairy products.  Higher levels of zinc may interfere with copper absorption so many dietary supplements containing zinc also include copper.

 

AREDS Study

The Age Related Eye Disease Study (ARED’s) was a 10 year study sponsored by the National Institutes of Health (NIH).  The study showed that a specific combination of antioxidants and zinc slowed the progression of advanced age-related macular degeneration by approximately 25%.  The ARED’s formulation included vitamins A (as beta-carotene), C, E, zinc and copper.

 

AREDS2 Study

The AREDS2 Study was designed to determine if adding omega-3 fatty acids or lutein and zeaxanthin would make it more effective.  A secondary goal was to determine if eliminating beta-carotene from the formula would be detrimental (A different study showed a relationship between beta-carotene and lung cancer in smokers). A third goal of the study was to determine if decreasing the amount of zinc would be detrimental.  The study determined that replacing beta-carotene with lutein and zeaxanthin was neither better nor worse than the original AREDS formula O.S.

Omega-3 fatty acids

Omega-3 and Omega-6 fatty acids are considered essential because our bodies cannot produce them on their own.  We must get them from the foods we eat  Omega-3 fatty acids play important role in brain function and we think in retinal function.  The retina has the highest concentration of omega-3 fatty acids in the body.  Omega-3 has been shown to have benefits for reducing heart disease.  Good sources of omega-3 fatty acids are fatty fish, such as mackerel, trout, herring, sardines, tuna and salmon.  Omega-3 fatty acids are blood thinners and excess supplements can lead to problems.

Vitamin D

Vitamin D is a fat-soluble hormone that has been shown to be a factor in controlling bone disease, some types of cancer and tooth decay.  A 2007 study of 7,000 people indicated that those with the higher blood levels of Vitamin D were less likely to show early signs of macular degeneration.  Good sources of vitamin D are Dairy products, oysters and fatty fish.  Your body can produce its own vitamin D when exposed to direct sunshine.  If taking supplements, use caution.  Excess vitamin D can be toxic.

Co-enzyme CoQ10

CoQ10 is associated with increased metabolic activity.  Studies have shown that CoQ10 levels in the retina decrease with age so we think that increasing its level might slow the progression of the disease.  Wheat germ and fish are good natural sources of CoQ10.  The appropriate supplement level is thought by many to be 100 mg/day.

Trans-reveratrol

Trans-resveratrol is another antioxidant although not as strong as Vitamin C and E.  A few studies have shown some benefit in macular health.  Trans-reveratrol also lowers LDL cholesterol and may be a factor in cancer prevention.   It is found in red grapes and wine.  A safe supplement level may be 50mg/day.

EGCG

EGCG is another antioxidant, which may play a role in macular degeneration as well as cancer prevention.  It is most commonly found in green tea.  One cup of green tea contains about 400mg.  It is thought that only one or two cups/day is safe.

 

Wet Age-Related Macular Degeneration

Approximate 10% of people with Dry Age Related Macular Degeneration develop Wet Age Related Macular Degeneration.  Damaged retinal cells release a substance called VEGF which stimulates the growth of new retinal vessels (neovascularization).  These new blood vessels are very frail and often leak.

In Wet Age Related Macular Degeneration new blood vessels grow into the macula and then hemorrhage .  This form of the disease can be devastating.  Many patients lose all central vision and are legally blind.  The disease does not affect peripheral vision so patients are not totally blind.  In the past neovascularization was treated by laser, however the laser often also damage the macula further.

Anti-VEGF Drugs

Avastin and Lucentis are Anti-VEGF drugs that block the growth of  the abnormal blood vessels and reduce the leakage of fluid from the vessels. Lucentis was approved by the U.S. Food and Drug Administration (FDA) in 2006 for the treatment of AMD.  Avastin is very similar to Lucentis but is not approved by the FDA for this purpose.  Avastin is cheap ($40/dose), but Lucentis is very costly ($2,000/dose) .  A 2012 study found that They are equally effective in treating age-related macular degeneration.  Most often injections are given monthly or bimonthly.  Studies indicate that approximately 50% of eyes treated with these drugs remain stable.  We are seeing much better outcomes now compared to before these drugs were available.

 

Recommendations:

Ideally your diet should include ample quantities of these antioxidants, but if you are at risk for macular degeneration or have the disease, supplementation may be advisable.  There are several companies that make supplements with these antioxidants.  If you are taking supplements, use as directed.   High doses of  many of these items are toxic and can cause side effects.

 

If you have Dry Age Related Macular Degeneration I would recommend taking two Bausch & Lomb PreserVision AREDS2 Soft Gel©  supplement  twice a day with food (That’s 4 capsules per day).   If you do not have macular degeneration, but are at risk of developing it, you may only take one capsule twice a day with food.  If you have Wet Age Related Macular  Degeneration consult with your retinal specialist concerning the use of supplements and the advisability of Anti-VEGF  therapy.

 

PreserVision AREDS2 image

PreserVision AREDS2

Vitamin A      0 mg

Vitamin C   226 mg

Vitamin E   200 mg

Zinc             35 mg

Copper          1 mg

Luetin           5 mg

Zeaxanthin    1 mg

Selenium        0 mg

Omega-3    500 mg

 

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