Zinc and Antioxidants May Delay Progression of Age-Related Macular Degeneration

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MedscapeWire

Zinc and Antioxidants May Delay Progression of Age-Related Macular Degeneration

October 15, 2001

New York - In people older than 55 years who have findings on dilated eye exams

that indicate intermediate age-related

macular degeneration, a supplement of antioxidants plus zinc may delay

progression of the disease, according to an

Archives Express article in the October issue of the Archives of Ophthalmology.

Researchers with the Age-Related Eye Disease Study (AREDS, Report No. 8) studied

3640 individuals aged 55 to 80 years

for an average of 6.3 years who were evaluated for signs of age-related

degeneration of the macula (AMD), the leading

cause of visual impairment and loss in people over age 65.

The researchers evaluated the effect of high-dose vitamins C and E, beta

carotene, and zinc supplements on AMD

progression and visual acuity. The observational and experimental data suggest

that antioxidant and/or zinc supplements

may delay progression of AMD and vision loss. Participants with signs of early

AMD who took antioxidants plus zinc

significantly reduced their risk of developing advanced AMD.

The participants were divided into 4 categories based on preexisting eye lesions

and degeneration present before the

study, roughly corresponding to their risk of AMD progression. They were

evaluated every 6 months for retinal changes

indicating AMD progression. The participants were randomly assigned to receive 1

of 4 daily supplements:

1) antioxidants (vitamin C, 500 mg; vitamin E, 400 IU; and beta carotene, 15

mg)

2) zinc, 80 mg, as zinc oxide; and copper, 2 mg, as cupric oxide

3) antioxidants plus zinc

4) placebo

" Comparisons with placebo demonstrated a statistically significant odds

reduction for the development of advanced AMD

with antioxidants plus zinc [28% reduced risk], " the researchers write.

" The [reduced risks] for zinc alone and antioxidants alone are [25%] and [20%]

respectively, " they add. " The only

statistically significant reduction in rates of at least moderate visual acuity

loss occurred in higher-risk persons

assigned to receive antioxidants plus zinc [27% reduced risk]. "

The authors note that the doses of vitamins C and E and the dose of zinc used in

the study are higher than the

recommended daily amount and therefore can only be obtained by taking

supplements. They recommend that, because of

adverse effects documented in other studies, smokers should not take beta

carotene.

" Based on data from AREDS, persons older than 55 years should have dilated eye

examinations to determine their risk of

developing advanced AMD, " the authors conclude. " Those with extensive

intermediate size drusen, at least one large

druse, or noncentral [atrophy] in one or both eyes or those with advanced AMD or

vision loss due to AMD in one eye, and

without contraindications such as smoking, should consider taking a supplement

of antioxidants plus zinc such as that

used in this study. "

In a related article, with AREDS (Report No. 9) found that a high-dose

formulation of vitamin C, vitamin E and beta

carotene had no apparent effect on reducing the risk of development of

age-related cataract.

In an accompanying editorial, Lee M. Jampol, MD, of the Department of

Ophthalmology at Northwestern University, Chicago,

notes that in the growing trend to prevent or ameliorate medical conditions and

the aging process, many patients

" attack " by taking various supplements. He states that because the cause of AMD

is uncertain, it is difficult to

determine what supplements might be helpful.

Dr. Jampol states that, " Surprisingly and fortunately, [the AREDS] results

demonstrate impressive efficacy of the

interventions for intermediate and advanced AMD. This contrasts with the

disappointing results to date of similar

supplementation for the prevention of cancer, stroke and cardiovascular

disease. "

Dr. Jampol notes that, " ... the study tells us nothing about the value of

supplementation in [Categories 1 and 2].

Supplementation was not demonstrated to prevent progression from Category 2 to

category 3 or 4.

" Only the combination of zinc and antioxidants statistically reduced the odds of

patients developing advanced AMD, " Dr.

Jampol states. " The only statistically significant reduction of moderate visual

loss occurred in patients assigned to

antioxidants plus zinc.

" ... the results do demonstrate a consistent and cohesive picture of the modest

efficacy of the zinc alone, the

antioxidants alone, and more of an effect from the combination of the 2, " Dr.

Jampol observes. " We do not, of course,

know whether 1, 2, or all 3 of the antioxidants are responsible for the

beneficial effect.

" I would conclude that those patients of any age who demonstrate extensive

intermediate sized drusen, large drusen, or

especially those who have advanced AMD in one eye, should consider taking a

supplement containing these dosages of

anti-oxidants and zinc, Dr. Jampol summarizes. " It seems desirable that this

supplement should be taken indefinitely,

though AREDS cannot determine ideal duration of treatment. "

According to background information in the article, AMD is the leading cause of

visual impairment and blindness in the

United States and elsewhere among people 65 years and older. There is no proven

treatment to slow or prevent development

of advanced AMD.

Arch Ophthalmol. 2001;119:1417-1436, 1439-1452, 1533-1534

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Good Health & Long Life,

Greg ,

http://www.ozemail.com.au/~gowatson

gowatson@...