September 2010

 

OPHTHALMOLOGY NEWS

 

Using lutein to stave off RP


by Maxine Lipner Senior EyeWorld Contributing Editor

   

Dietary regime makes RP treatable

Lutein supplementation can help retinitis pigmentosa (RP) patients already on vitamin A to extend their vision by up to 10 years, according to Eliot L. Berson, M.D., professor of ophthalmology, Harvard Medical School, Boston, and director, Berman-Gund Laboratory, Massachusetts Eye and Ear Infirmary, Boston. In the April issue of Archives of Ophthalmology, investigators lead by Dr. Berson reported that use of 12 mg per day of lutein slowed visual field loss among non-smoking adults with typical RP.

The idea for lutein supplementation in RP cases was an outgrowth of earlier work. "The impetus came from a close review of our vitamin A and E trial for retinitis pigmentosa conducted from 1984 to 1991," Dr. Berson said. "We found that those people who were consuming lutein or taking a lutein pill were doing better than those who were not." When investigators looked at the vitamin A group in particular, they could see a significant beneficial effect on saving the visual field and a near significant effect on preserving (outcomes on) the electroretinogram (ERG). "This prompted us to think that lutein might provide additional benefit to vitamin A," Dr. Berson said.

Studying lutein's effect

The 225 patients included in the randomized, controlled, double-masked trial were those with typical forms of RP who were night deficient, with narrowing of the retinal arterioles and a reduced and delayed light-evoked response from the retina or ERGs. Investigators randomized these patients who were taking a therapeutic dose of 15,000 IU a day of vitamin A palmitate to receive either lutein or a control pill. "The patients were also randomized by genetic type and by being above and below the so-called median serum lutein population so that we would have a balance with respect to comparable numbers in both groups with different genetic types," Dr. Berson said. "That way they would start out with approximately the same lutein level so that the lutein supplement would truly be additive to one group and not to the other."

At the four-year mark investigators determined that those on the lutein regimen were more likely to have preserved vision. "The key finding was that lutein supplementation on average slowed the loss of mid-peripheral field in patients with RP at the .05 level of significance," Dr. Berson said. "What we also found observationally is that the people who had the highest serum lutein levels and the highest intra-retinal macular pigment optical density, which is a measure of intra-retinal lutein, had the slowest rate of decline of disease."

Investigators found that it served as a way of slowing RP by preserving the visual field in the periphery. "We did not observe a significant treatment effect on preserving central field or acuity," Dr. Berson said. "So this is a treatment for mid-peripheral field."

Dr. Berson hypothesizes that the lutein is acting as an antioxidant here. "We think that lutein serves as a so-called antioxidant, binding free oxygen particles in the retina normally and probably becomes more critical when the disease is more advanced in a given region of the retina," he said.

"Since the disease is more advanced in the mid-periphery, at the time that these people are studied relative to the center, we hypothesize that lutein may function as an antioxidant stabilizing the most impaired retinal cells in the mid-periphery." He thinks that it is possible that as the central retina becomes more impaired, lutein may play a role as well.

Clinical impact

Patients on a lutein regime may be able to keep their visual decline at bay for years. "The benefit we calculated from the lutein supplementation was 3 to 10 years," Dr. Berson said. "If the lutein gets into the retina particularly, then the benefit could be on the order of 10 years on average." In addition, previous research has shown that patients can gain time by taking therapeutic levels of vitamin A. "This is additive to vitamin A, which we proposed has at least seven years of visual preservation," Dr. Berson said. "Also, an oily fish diet can increase the benefit of vitamin A by several years." All told, he sees this regimen as possibly staying the disease for several decades. "In my opinion, an average patient who starts this regimen by age 40 could expect a 20-year benefit," he said.

Specifically, the regimen includes use of 12 mg a day of lutein in conjunction with taking 15,000 IU a day of vitamin A palmitate and eating one to two three-ounce servings of oily fish such as salmon or tuna once a week. Dr. Berson stressed that vitamin A palmitate, not the more common beta carotene form frequently stocked in stores, should be used here. "Beta carotene is not a suitable substitute for vitamin A palmitate," he said. This can be difficult to find. Two sources that Dr. Berson has found are Freeda Vitamins, Long Island City, N.Y., and J.R. Carlson Laboratories, Arlington Heights, Ill. Dr. Berson said that this regimen is not for everyone. "This is not a regimen for smoking adults, pregnant women, children under the age of 18, or for atypical or unusual forms of RP," he said. Dr. Berson hopes that the study sends a clear message that RP is a treatable disease. "Since the majority of patients without treatment will have a significant loss of vision by age 60, if they get on this regimen they might be able to see a 20-year benefit," he said. "We want to emphasize that while we have not had any toxic effect of lutein or vitamin A supplementation, patients should check their fasting vitamin A and liver function before starting treatment and annually thereafter." Overall, Dr. Berson is very optimistic about the future for RP patients. "They should be hopeful that because of our increased understanding of the disease, there may be other treatments that will come along," he said. "They shouldn't feel that because they have RP they're necessarily going to lose their vision."

Editors' note: Dr. Berson has no financial interests related to his comments.

Contact information

Berson: 617-573-3621, Linda_Berard@meei.harvard.edu

Using lutein to stave off RP Using lutein to stave off RP
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