Research shows that many diseases - including cancer, cardiovascular disease, stroke, inflammatory joint disease, and degenerative conditions of the nervous system - are caused by a process called oxidation.  Unstable and highly reactive molecules in the body called free radicals mediate this process.  Oxidation by free radicals also appears to be involved in the development of certain eye diseases, including cataracts and age-related macular degeneration (AMD).¹

Because oxidation by free radicals appears to cause a wide variety of diseases, researchers are focusing on the possible protective role of antioxidant vitamins and other micronutrients.  Antioxidants are radical-scavenging agents that destroy free radicals and protect the body from harmful oxidative processes. 

Examples of antioxidants include:

•  Vitamin C

•   Vitamin E

•   Coenzyme Q

•  Beta-carotene

•  Carotenoids

•  Alpha-lipoic acid

•  Zinc

Fighting Macular Degeneration with Antioxidants

Research shows that antioxidants may lower the incidence of age-related macular degeneration (AMD) or at least slow the progression of the disease: 

• Vitamin E was associated with a 13% reduced risk of AMD in a 12-year study of 22,000 male physicians. 

•  A study of patients with signs of AMD showed those who took zinc supplements had less visual loss from the disease compared to patients receiving a placebo.²

•  In 1994, the Eye Disease Case Control Study indicated that dietary carotenoids, particularly lutein and zeaxanthin, slowed the progression of AMD.  People who ate the most green leafy vegetables were 88 percent less likely to develop severe AMD than subjects who ate the least amount of green leafy vegetables.³

Recommendations for Good Health and Clear Vision

On the basis of these and other studies that show the possible benefits of antioxidants in preventing systemic and eye diseases, many physicians and eye doctors recommend that you take the following steps to improve your body's ability to fight free radicals and harmful oxidative processes:

•  Eat a balanced diet rich in fruits, vegetables, and whole grains.

• Be physically active.  Exercise stimulates the production of enzymes involved in antioxidant activity.

• Don't smoke.  Cigarette smoke promotes the formation of free radicals in the body.  Studies also show that smoking reduces the level of vitamin C and probably other antioxidants in the body.

In addition, many experts recommend you ingest the following levels of antioxidant vitamins and micronutrients daily:

For most vitamins, the differences between natural and synthetic sources are not important.  But most experts agree the natural form of vitamin E (called d-alpha tocopherol) is more effective than the synthetic variety (dl-alpha tocopherol). 

Unless you are a person with proven iron-deficiency anemia or a woman of menstruating age, choose a multivitamin that does not contain iron.  Iron is an oxidizing agent that can promote heart disease and cancer, and the body cannot eliminate excess amounts except through blood loss.⁴

If it is difficult to find vitamin supplements with significant levels of lutein, beta-carotene and other carotenoids, increase your daily intake of the following carotenoid-rich foods:

Carotenoid-Rich Foods

Source: J Am Diet Assoc 1993;93:284-295. 

References

¹Ribble D. Antioxidants and eye disease. Ophthalmol Management; March 2000 suppl.

²Newsome DA, et al.  Oral zinc in macular degeneration. Arch Ophthalmol; 106:2, 192-8, 1988.

³Eye Disease Case-Control Study Group.  Antioxidant status and neovascular age-related macular degeneration. Arch Ophthalmol: 111:1, 104-9, Jan 1993.

⁴Weil A. Vitamin Week: How good are multis. http://www.drweil.com/archiveqa/0,2283,163,00.html.