Antioxidant eye vitamins or eye and age-related macular degeneration (AMD)

What are oxidation, free radicals and anti-oxidants?

Oxidation is a process to convert food into energy (ATP), during which an atom/molecule loses electrons. It may at times produce free radicals, which may set off chain reactions that may damage cells (for a more technical explanation: Being lacking electrons, a free radical is constantly looking for one to stabilize, thus very active).

Antioxidants, having extra electrons, can donate electrons to a free radical to stabilize it (to calm it down) so it will not wreak havoc.

Theory has it that cumulative damage by free radicals may account for many of the degenerative changes of aging and many age-related diseases such as AMD.

This is the basis of using anti-oxidant eye vitamins to treat (not to prevent, though) AMD.

This post is not about AMD, I will simply post this diagram from Harvard Health Letter so you have a rough idea of what is AMD. The prevalence of AMD by age is: age 65-74 (1%); age 75-84 (4.6%); age 85+ (13.1%). I believe the prevalence is much lower for Asian population.

AREDS

A landmark study, the Age-Related Eye Disease Study (AREDS) was reported in October 2001 issue of Archives of Ophthalmology, conducted by National Eye Institute, 4,757 participants for an average of 6.3 years between 1992 and 2001, showing a combination of beta carotene, vitamin D and C and E, zinc and copper can slow or prevent progression in about 25% of those who already have AMD.

Concern was raised as carotene is associated with increased risk of lung cancer in current or former smokers. Zinc dose was lowered as it can cause stomach upset and other side effects.

AREDS2

Several modified regimens were used subsequently in AREDS2 study, using lutein and zeaxanthin to replace carotene, and omega-3 fatty acid was added, the result was reported in 2013: no better and no worse comparing with the AREDS using the original AREDS vitamin cocktail. So the AREDS2 vitamin cocktail also works, as well as, although no better than, the original AREDS regimen.

What are lutein, zeaxanthin and beta-carotene?

Beta-carotene is transformed into vitamin A which is essential to eye health.  Vitamin A is required by the retina to detect the light and convert it to electrical signal.  Lutein and zeaxanthin are the only carotenoids found in the retina of the eye, doing the same job as vitamin A, they can be treated as natural antioxidants. Spinach and kale, lutein-rich vegetables appear to moderately reduce the risk of cataract beside the benefit to AMD.

AREDS2 formula (PreserVision: made by Bausch + Lomb):

Vitamin C 500 mg

Vitamin E 400 IU

Zinc 80 mg (25 mg in the AREDS2 study)

Copper 2 mg

Lutein 10 mg

Zeaxanthin 2 mg

(No beta-carotene)

Do I need to take anti-oxidant eye vitamins?

The other day while at Sam’s Club I picked up a bottle of PreserVision (made by Bausch + Lomb), which is touted as AREDS2 formula.  I am well aware that AREDS showed no benefit from antioxidant vitamins in those who did not already have AMD, in other words, they didn’t prevent one from getting AMD, nor would it improve vision.

Not known to have AMD, why would I need to take antioxidant vitamins? The rationale is that for those who do not see an eye doctor (ophthalmologist) often or regularly, AMD cannot be picked up at its very early stage, taking them, just in case. I mention this to make a point that we all (including myself, a medical doctor) are not doing thing the way it should when it comes to medical care.

There is no substitute to seeing an eye doctor (ophthalmologist). Dr. Jeffrey Heier from Massachusetts Eye and Ear Infirmary said “the exam can determine if you will benefit from vitamins.” Dr. Heier advises against taking anti-oxidant eye vitamins unless one has AMD, although he does encourage eating nutritious diet rich in green, leafy vegetables not only for one's eyes, but for one's overall health.

Ways to protect your eyes from AMD

1. Sunlight thought to possibly promote AMD, wear sunglasses or broad-brimmed hat if necessary.
2. Indulge in fresh fruits and dark-green leafy vegetables, such as spinach, collard greens, kale, they are rich in lutein and zeaxanthin.
3. Smoking can speed up the process of AMD.
4. Consult your eye doctor is the only sure way to find out whether you need to take antioxidant eye vitamins or not.

Kales in our garden: rich in lutein and zeaxanthin