Writing in the Archives of Ophthalmology, American scientists report that a daily supplement containing 12 milligrams of lutein in combination with 15,000 International Units of vitamin A (retinyl palmitate) was associated with a preservation of mid-peripheral vision.
Rentinitis pigmentosa is a group of inherited eye diseases that affect the retina. It causes the degeneration of photoreceptor cells in the retina, bringing progressive vision loss to about one in 4,000 people worldwide. Previous studies had found that taking vitamin A slows the decline in retinal function and vision loss.
The new data indicates that 40 year olds with the condition who take the vitamin A plus lutein combination would not be expected to lose their mid-peripheral field until the age of 61, which would represent a significant improvement compared with only 51 in people not taking supplements of the carotenoid.
Lutein for eyes
Lutein, a nutrient found in various foods including green leafy vegetables and egg yolk, has a ten-year history in the dietary supplement market as a nutrient to reduce the risk of age related macular degeneration (ADM). It is often used in combination with zeaxanthin.
The global lutein market is set to hit $124.5 million (€93 million) in 2013, according to a 2007 report from Frost & Sullivan.
According to the report, manufacturers need to address this growing maturity in dietary supplements by identifying new and potentially lucrative application segments that offer opportunities for the continued growth of the lutein market.
Study details
Led by Eliot Berson, MD, from the Massachusetts Eye and Ear Infirmary, the researchers recruited 225 non-smoking people with retinitis pigmentosa aged between 18 and 60. The participants were randomly assigned to receive vitamin A only (15,000 IU, retinyl palmitate) or vitamin A plus lutein (12 mg per day) for four years.
While no significant effect was observed for the overall decline in vision between the two groups, a significant reduction in the rate of vision loss in the mid-peripheral region was observed.
According to the researchers, the average level of mid-peripheral sensitivity for a patient aged 40 years is 375 dB. People taking the lutein supplements lost on average 27 dB per year, while the other group lost 34 dB per year, noted the researchers.
Safety
No toxicity concerns were recorded during the study, and the researchers noted that only non-smokers took part in their study. Berson and his co-workers stated that there has been concern for smokers taking long-term lutein supplementation.
“Follow-up of patients taking lutein and vitamin A with an oily fish diet for at least 10 years would be needed to confirm these estimates with respect to preserving midperipheral visual field,” concluded the researchers.
Source: Archives of Ophthalmology
2010, Vol. 128, Issue 4, Pages 403-411
"Clinical Trial of Lutein in Patients With Retinitis Pigmentosa Receiving Vitamin A"
Authors: E.L. Berson, B. Rosner, M.A. Sandberg, C. Weigel-DiFranco, R.J. Brockhurst, et al.