Adding fish oil or omega-3 fatty acids such as those in fish oil or the supplement lutein/zeaxanthin to a recommended cocktail of vitamins C and E, beta carotene and zinc did not further reduce the progression of the vision-destroying condition, age-related macular degeneration, said a consortium of researchers that included those from Baylor College of Medicine in an online report in the Journal of the American Medical Association. The report was released early in conjunction with a presentation at the Association for Research in Vision and Ophthalmology meeting in Seattle, Wash.
"It does not surprise me," said Dr. Richard Lewis, professor in the department of ophthalmology at BCM and the principal investigator of the BCM study site. "More and more evidence is accumulating that the much-hoped for benefits of fish oil supplements for heart disease and other vascular problems are not real. This study clearly shows that these supplements provide no added benefits for preventing vision loss from macular degeneration over five years."
While a previous national study had shown that the recommended supplement cocktail of antioxidant vitamins and zinc did slow progression of the disorder, this second study confirms that fish oil or lutein/zeaxanthin added to the existing vitamins and minerals had no effect.
The study was a large one. Nationwide, the study enrolled 4,203 people ages 50 to 85 who were at risk of developing advanced stages of the disorder.
All study participants received the originally recommended "AREDS" cocktail of supplements. They were then randomly assigned to four treatment groups of additional supplements: placebo (inactive medication that looks like the other medicines; lutein plus zeaxanthin; DHA plus EPA(the ingredients in fish oils); or lutein plus zeaxanthin and DHA plus EPA (that is, both additional supplements). Some participants were also asked to accept a second random assignment to four groups in which the recommended cocktail was changed. Those who accepted that second random assigned received a lower dose of zinc, received no beta carotene, or both.
All those in the study underwent a variety of tests of their eye health and ability to see at the beginning of the study and some were done at regular intervals in between and at the end of the five year study.
A total of 1,608 of those in the study had had an event indicating that they progressed to advanced macular degeneration by the end of the study. However, the risk of progressing to advanced macular degeneration in each of the four treatment groups was the same statistically.
For participants who smoked or had smoked in the past year, beta carotene was eliminated from the formulation because it had been shown in other studies to increase the risk of lung cancer. The researchers also reduced the level of zinc for some participants. Neither change affected the risk of progressive macular disease, the researchers said.
The researchers said that substituting lutein and zeaxanthin for beta carotene in the recommended cocktail might be considered in the future.
In a second study that appeared in JAMA Ophthalmology, researchers found that the addition of either of the newer added supplements had no effect on the risk of developing cataracts.