|AREDS 2 Results|
The National Eye Institute released the five-year results of AREDS 2 this week, at ARVO, the annual meeting of the Association for Research in Vision and Ophthalmology. This follow-up to the Age-Related Eye Disease Study (AREDS) looked at changing the formula for the AREDS supplement. Specifically, they studied the effect of adding lutein, zeaxanthin and omega-3 to the original formula. The results showed that lutein and zeaxanthin may be helpful, but omega-3 did not have a positive effect over five years.
The original AREDS formula contains:
15 mg betacarotene
There were several issues with this formula. It is known that betacarotene may promote lung cancer in smokers. The level of zinc is very high and did cause some gastrointestinal problems in patients in the original study. AREDS did not contain lutein and zeaxanthin. At the time the study began, there were some indications that lutein might be helpful. But, there was no reliable source of large quantities of these carotenoids, so it was not included in AREDS.
The AREDS 2 research was designed to identify the effect of several things:
In addition, they wanted to find the effect of:
Neither the 4,203 participants nor the researchers knew which formula they were receiving or if they were getting a placebo. The individuals were assigned randomly to the various groups. It's important to note that the serum levels of lutein/zeaxanthin and the dietary habits of the participants were also measured. This may turn out to be important in later analysis.
At the end of the research, they looked at:
The study showed that removing the betacarotene and lowering the zinc did not have an effect on the progression rate. Lung cancer rates were higher in the betacarotene group, mostly in former smokers who had stopped smoking more than a year before. It was noted that about 50% of AMD patients are smokers or former smokers, so this is an important finding.
Lutein and zeaxanthin would be appropriate substitutes for betacarotene and they did not cause any increase in the risk of lung cancer. In addition, betacarotene competes for absorption with lutein and zeaxanthin, so they should not be taken together or the positive effects will be reduced, as they were in this clinical trial.
The original AREDS formula reduced the risk of progression to advanced AMD. Adding lutein and zeaxanthin provided about a 20% reduction in progression beyond the original AREDS, In those who had the lowest dietary intake of lutein and zeaxanthin.
The addition of omega-3 did not reduce the risk of progression.
The development of cataract was not affected by any of the supplements.
There is insufficient data to make recommendations about the level of zinc. Given the choice, 90% of AREDS 2 participants also took Centrum, which has 15 mg of zinc. According to Dr. Chew, this high level of zinc (about 95 mg when combined with AREDS 2) worked and was not harmful. By the way, participants in the original AREDS research also took Centrum.
The results led the researchers at the National Eye Institute to recommend that the AREDS formula be adjusted by the removal of betacarotene and addition of lutein and zeaxanthin.
500 mg vitamin C
Dr. Chew stated, "We hope that this formulation will be a safer and more efficacious one for our patients. It simplies the patient's life... We have one formulation that will be for smokers and nonsmokers and which hopefully will be successful in reducing the risk of advanced macular degeneration."
The rest of the story
This study collected a mountain of data and the researchers will be digging through it for years.
One area of interest relates to diet. The people in the study, as a whole, were very well nourished and well educated. Still, the participants who got the most benefit from the supplement had the worst diets. They also showed the most improvement in the level of lutein and zeaxanthin in their blood. Dr. Chew is curious to evaluate the participants with the lowest dietary intake of lutein and zeaxanthin to see if their cataracts developed differently from those more highly nourished. Clearly, there is a lot more to be learned here and a lot more detail to tease out. The NEI is very interested in continuing this analysis.
Participants are still being followed every 6 months and we surely will be hearing more results from this important AREDS 2 research.