Age-Related Eye Disease Study

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The Age-Related Eye Disease Study (AREDS) was a clinical trial sponsored by the National Eye Institute, one of the National Institutes of Health in the United States. The study was designed to

• investigate the natural history and risk factors of age-related macular degeneration (AMD) and cataracts, and
• evaluate the effects of high doses of antioxidants and zinc on the progression of the two conditions in those with AMD

The study followed 3640 individuals for an average of 6.3 years between 1992 and 2001. The researchers concluded that high levels of antioxidants and zinc can reduce some people's risk of developing advanced AMD by about 25 percent. Those that benefited from the dietary supplements included those with intermediate-stage AMD and those with advanced AMD in one eye only. The supplements had no significant effect on the development or progression of cataracts. "High levels" in this case were defined to be:

• 500 milligrams of vitamin C;
• 400 international units of vitamin E;
• 15 milligrams of beta-carotene (or 25,000 international units of vitamin A);
• 80 milligrams of the dietary mineral zinc, in the form of zinc oxide; and
• two milligrams of copper as cupric oxide, added to prevent copper deficiency anemia, a condition associated with high levels of zinc intake.

The results were reported in the October 2001 issue of Archives of Ophthalmology.

Bausch & Lomb was a collaborator in the study and provides vitamins pre-packaged with this formulation, sold commercially as Ocuvite PreserVision antioxidant vitamin and mineral supplement, as do other suppliers.

Video Age-Related Eye Disease Study

AREDS2

The study was followed by AREDS2, a five-year study (starting 2006) designed to test whether the original AREDS formulation would be improved by adding omega-3 fatty acids; adding lutein and zeaxanthin; removing beta-carotene; or reducing zinc. In AREDS2, participants took one of four AREDS formulations: the original AREDS formulation, AREDS formulation with no beta-carotene, AREDS with low zinc, AREDS with no beta-carotene and low zinc. In addition, they took one of four additional supplement or combinations including lutein and zeaxanthin (10 mg and 2 mg), omega-3 fatty acids (1,000 mg), lutein/zeaxanthin and omega-3 fatty acids, or placebo.

The study reported that there was no overall additional benefit from adding omega-3 fatty acids or lutein and zeaxanthin to the formulation. However, the study did find benefits in two subgroups of participants: those not given beta-carotene, and those who had very little lutein and zeaxanthin in their diets. Removing beta-carotene did not curb the formulation's protective effect against developing advanced AMD, which is important given that high doses of beta-carotene have been linked to higher risk of lung cancers in smokers. According to Dr. Emily Chew, "Because carotenoids can compete with each other for absorption in the body, beta-carotene may have masked the effect of the lutein and zeaxanthin in the overall analysis."

Maps Age-Related Eye Disease Study

References

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External links

• NEI's website about the AREDS study
• NEI's website about the AREDS2 study

Source of the article : Wikipedia