Prominent international researchers have shown the AREDS2 formula, using the antioxidants lutein and zeaxanthin instead of beta-carotene supplements, not only reduces risk of lung cancer, but is more effective at reducing risk of AMD progression.
The study, published in JAMA Ophthalmology and funded by US medical research agency National Institutes of Health (NIH), followed up 3,883 of the original 4,203 AREDS2 participants to analyse 10 years of data.
After a decade, the group originally assigned lutein/zeaxanthin had an additional 20% reduced risk of progression to late AMD compared to those originally assigned beta-carotene.
The Age-Related Eye Disease Studies (AREDS and AREDS2) originally established that dietary supplements can slow progression of AMD.
But because beta-carotene reportedly increased the risk of lung cancer for current smokers in two NIH-supported studies, the AREDS2 study aimed to create an equally effective supplement formula that could be used by anyone, regardless of whether they smoked.
“This 10-year data confirms that not only is the new formula safer, it’s actually better at slowing AMD progression,” Dr Emily Chew, director of the Division of Epidemiology and Clinical Application at the National Eye Institute (NEI), and lead author of the study report, said.
The original AREDS study, launched in 1996, showed 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 significantly slow the progression of AMD from moderate to late disease.
However, two concurrent studies also revealed people who smoked and took beta-carotene had a significantly higher risk of lung cancer than expected.
In AREDS2, commenced in 2006, Chew and her colleagues compared the beta-carotene formulation to one with 10 mg lutein and 2 mg zeaxanthin instead. The beta-carotene-containing formation was only given to participants who had never smoked or who had quit smoking.
At the end of the five-year AREDS2 study period, the researchers concluded that lutein and zeaxanthin did not increase risk for lung cancer, and that the new formation could reduce the risk of AMD progression by about 26%.
After the completion of the five-year study period, the study participants were all offered the final AREDS2 formation that included lutein and zeaxanthin instead of beta-carotene.
In the new report, the researchers followed up with 3,883 of the original 4,203 AREDS2 participants, an additional five years from the end of the AREDS2 study in 2011, collecting information on whether their AMD had progressed to late disease, and whether they had been diagnosed with lung cancer.
Even though all the participants had switched to the formula containing lutein and zeaxanthin after the end of the study period, they reported that the follow up study continued to show that beta-carotene increased risk of lung cancer for people who had ever smoked by nearly double.
There was no increased risk for lung cancer in those receiving lutein/zeaxanthin.
In addition, after 10 years, the group originally assigned to receive lutein/zeaxanthin had an additional 20% reduced risk of progression to late AMD compared to those originally assigned to receive beta-carotene.
“These results confirmed that switching our formula from beta-carotene to lutein and zeaxanthin was the right choice,” Chew added.
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