Dietary supplements may delay age-related macular degeneration progression, NIH study finds

03 Jun 2022 --- Dietary supplements can decrease the advancement of age-related macular degeneration (AMD), the most prevalent cause of blindness in older citizens, according to the Age-Related Eye Disease Studies (AREDS and AREDS2) – funded by the National Institutes of Health (NIH). AMD is a degenerative disease of the retina, the light-sensitive tissue at the back of the eye.

When reviewing ten years of AREDS2 data, researchers found that the AREDS2 formula – which replaced beta-carotene with antioxidants lutein and zeaxanthin – reduces the risk of lung cancer due to beta-carotene but also reduces the risk of AMD progression when compared to the original formula (that included beta-carotene, copper and vitamins).

“Because beta-carotene increased the risk of lung cancer for current smokers in two NIH-supported studies, our goal with AREDS2 was to create an equally effective supplement formula that anyone could use, whether or not they smoke,” says Emily Chew, lead study author and director, division of Epidemiology and Clinical Application at the National Eye Institute.

“These results confirmed that switching our formula from beta-carotene to lutein and zeaxanthin was the right choice,” she continues. “This ten-year data verifies that not only is the new formula safer, it is also better at slowing AMD progression.”

Examining beta-carotene versus lutein and zeaxanthin
Although treatment can reduce or reverse the visual loss, there is no cure for AMD.

Although treatment can reduce or reverse the visual loss, AMD has no cure, which affects the eye’s retina.Blindness results from the death of retinal cells in the macula, the portion of the retina that provides crisp center vision.

The first AREDS trial, which began in 1996, found that a dietary supplement formulation (500 mg vitamin C, 400 international units vitamin E, 2 mg copper, 80 mg zinc and 15 mg beta-carotene) could considerably reduce the progression of AMD from moderate to late disease.

People who smoked and took beta-carotene, on the other hand, had a significantly higher risk of lung cancer than expected, according to two separate studies.

Chew and colleagues compared the beta-carotene formulation to one containing 10 mg lutein and 2 mg zeaxanthin in AREDS2, which began in 2006. Lutein and zeaxanthin, like beta-carotene, are antioxidants that have activity in the retina. Only those who had never smoked or had recently stopped were given the beta-carotene-rich formulation.

The researchers determined that lutein and zeaxanthin did not raise the risk of lung cancer over the five-year AREDS2 study period. The new formulation could reduce the risk of AMD development by roughly 26%. After the five-year trial period, all study participants were given the final AREDS2 formulation, which contained lutein and zeaxanthin instead of beta-carotene.

Following up on AMD progression
In this new investigation, researchers followed up with 3,883 of the initial 4,203 AREDS2 participants for an additional five years after the study ended in 2011 to see if their AMD had progressed to late disease and if they had been diagnosed with lung cancer.An eye exam is performed by Dr. Emily Chew (Credit: National Institutes of Health).

Although all participants had converted to the lutein and zeaxanthin mixture by the end of the study, the follow-up analysis revealed that beta-carotene significantly doubled the risk of lung cancer in persons who had ever smoked.

Lung cancer risk was not enhanced in individuals who took lutein or zeaxanthin.

Furthermore, after ten years, the group that received lutein or zeaxanthin had a 20% lower chance of advancement than the control group.

By Nicole Kerr