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VA Research Currents archive
January 21, 2015
Navy Veteran Marty Sigel peruses the vision supplements at a Baltimore health food store. (Photo by Mitch Mirkin)
Vitamins and supplements are a billion-dollar industry in the U.S., with millions of Americans popping pills or capsules or swallowing powdered drinks to address everything from indigestion to heart and brain health. Now new research published in Ophthalmology, the journal of the American Academy of Ophthalmology, has found that some of the top-selling eye vitamins don't contain the same ingredient dosages shown effective in clinical trials. Some also contain additional ingredients not validated in clinical trials.
Furthermore, the study, led by researchers with the Providence VA Medical Center, Penn State University, Brown University, Yale-New Haven Hospital, and Waterbury Hospital, found that many of the claims published in promotional material lack scientific evidence.
The basis for the study is the landmark Age-Related Eye Disease Study (AREDS). AREDS found in 2001 that a specific formula of supplements containing high doses of zinc and other antioxidants could slow the deterioration of the eye's macula. Age-related macular degeneration (AMD) is the leading cause of blindness among older adults. The macula is the central part of the retina. It allows the eye to make out fine details.
A follow-up study concluded in 2011 that the formula remained effective even if one ingredient, beta-carotene, was replaced with related nutrients. The publication of the second study, AREDS2, solidified the benefits of the formula in treating AMD. Sale of supplements marked as containing either the AREDS or AREDS2 formula skyrocketed.
But it turns out, according to the new study, that some supplements are more marketing genius and less medical breakthrough.
For the study, the researchers identified the five top-selling brands of eye vitamins and analyzed 11 products made by the five companies.
All the products contained ingredients from either the AREDS or AREDS2 formula. However, only four of the products contained doses that were equivalent to those used in the studies. Another four products contained lower doses. Additionally, four contained additional vitamins, minerals, or herbal extracts that were not part of the original studies.
The researchers assert that without clinical research, it is impossible to determine how those additional ingredients alter the effectiveness of the AREDS and AREDS2 formulas.
Additionally, all the products were marketed with promotional materials claiming the supplements "support, "protect," "help," or "promote" vision and eye health. None of the product literature specified that the formulas used in AREDS and AREDS2 proved effective only in people with specific stages of AMD.
"With so many vitamins out there claiming to support eye health, it's very easy for patients to be misled into buying supplements that may not bring about the desired results," first author Dr. Jennifer J. Yong said in a news release.
"Our findings underscore the importance of ophthalmologists educating patients that they should only take the proven combination of nutrients and doses for AMD according to guidelines established by AREDS and AREDS2. It's also crucial that physicians remind patients that, at this time, nutritional supplements have yet to be proven clinically effective in preventing the onset of eye diseases such as cataracts and AMD," said Yong.
Dietary supplements are classified as foods and not drugs, per the Dietary Supplement Health and Education Act of 1994. As such, they do not require approval from the Food and Drug Administration.
