Claims about top-selling eye vitamins do not match scientific evidence, finds study
Of 11 supplements analysed, 7 do not adhere to proven formulas, and all make misleading claims
Some of the claims made about the benefits of top-selling eye vitamins lack scientific evidence while others do not adhere to proven formulas, a study published online in Ophthalmology, the journal of the American Academy of Ophthalmology, has found.
Not only do some of the products not contain identical ingredient dosages to eye vitamin formulas proven effective in clinical trials, but claims made on the products' promotional materials also lack scientific evidence.
The leading cause of blindness among older adults in the US is age-related macular degeneration (AMD). Recommended treatment for AMD at certain stages of the disease includes nutritional supplements.
The landmark Age-Related Eye Disease Study (AREDS) found in 2001 that a specific formula of nutritional supplements containing high doses of antioxidants and zinc could slow the worsening of AMD.
A follow-up study in 2011, AREDS2, determined that the formula was still effective if one ingredient, beta-carotene (a form of vitamin A), was replaced with related nutrients, lutein and zeaxanthin.
The two studies prompted a surge in sales of eye supplements marketed as containing the AREDS or AREDS2 formulas.
With so many vitamins out there claiming to support eye health, it's very easy for patients to be misled
To test whether the products are consistent with the studies' findings, researchers compared the ingredients in top-selling brands to the exact formulas proven effective by AREDS and AREDS2.
The researchers – based at Yale-New Haven Hospital-Waterbury Hospital, Penn State College of Medicine, Providence VA Medical Center and Warren Alpert Medical School of Brown University – identified the five top-selling brands based on market research collected from June 2011 to June 2012, and analysed the brands' 11 products.
They found that, while all of the products studied contained the ingredients from the AREDS or AREDS2 formulas:
- Only four of the products had equivalent doses of AREDS or AREDS2 ingredients
- Another four of the products contained lower doses of all the AREDS or AREDS2 ingredients
- Four of the products also included additional vitamins, minerals and herbal extracts that are not part of the AREDS or AREDS2 formulas
In addition, while all 11 of the products' promotional materials contained claims that the supplements 'support', 'protect', 'help' or 'promote' vision and eye health, none had statements explaining that nutritional supplements have only been proven effective in people with specific stages of AMD.
There were also no statements clarifying that currently there is not sufficient evidence to support the routine use of nutritional supplements for primary prevention of eye diseases such as AMD and cataracts.
'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,' said first author Jennifer Yong.
Details of the products studied are available here.