What are lutein, zeaxanthin and beta-carotene?
Lutein, zeaxanthin, and beta-carotene belong to a family of nutrients known as carotenoids. Carotenoids are made by plants and are especially enriched in green leafy vegetables. They can be stored in animal tissues and are found at relatively low levels in animal food products. In the body, beta-carotene is used to make Vitamin A, which is required by the retina to detect light and convert it into electrical signals. Beta-carotene itself is not found in the eye. In contrast, lutein and zeaxanthin are found in the retina and lens, where they may act as natural antioxidants and help absorb damaging, high-energy blue and ultraviolet light
What are omega-3 fatty acids?
Omega-3 fatty acids are made by marine algae and enriched in fish oils; they are believed to be responsible for the health benefits associated with regularly eating fish, including lower rates of cardiovascular disease. The AREDS2 study focused on the omega-3 fatty acids DHA and its precursor EPA. DHA is needed for the integrity of the retinal cells, and has been shown to promote retinal development and repair in prior studies.
Who should consider taking a combination of antioxidants and zinc like those examined in AREDS and AREDS2?
People at high risk for developing advanced AMD should consider taking the antioxidant-zinc combinations examined in AREDS and AREDS2. These people are defined as having either:
- Intermediate AMD in one or both eyes. Intermediate AMD can be detected by an eye care professional, but usually involves little or no vision loss.
Advanced AMD in one eye, but not the other eye. Advanced AMD involves either a breakdown of cells in the retina (called geographic atrophy or dry AMD), or the growth of abnormal blood vessels under the retina (called neovascular or wet AMD). Either of these forms of advanced AMD can cause vision loss.
Will taking an AREDS formulation prevent AMD?
There is no known treatment that can prevent the early stages of AMD. However, the AREDS formulations may delay progression of advanced AMD and help you keep your vision longer if you have intermediate AMD, or advanced AMD in one eye. The participants in the first AREDS trial have now been followed for 10 years, and the benefits of the AREDS formulation have persisted over this time.
Can I take a daily multivitamin if I am taking one of the AREDS formulations?
Yes. The AREDS formulation is not a substitute for a multivitamin. In the AREDS trial, two-thirds of the study participants took multivitamins along with the AREDS formulation. In AREDS2, almost nine of ten participants took multivitamins.
Can a daily multivitamin alone provide the same vision benefits as an AREDS formulation?
No. The vitamins and minerals tested in the AREDS and AREDS2 trials were provided in much higher doses than what is found in multivitamins. Also, it is important to remember that most of the trial participants took multivitamins. Taking an AREDS formulation clearly provided a benefit over and above multivitamins.
Can diet alone provide the same high levels of antioxidants and zinc as the AREDS formulations?
No. The high levels of vitamins and minerals are difficult to achieve from diet alone. However, previous studies have suggested that people who have diets rich in green, leafy vegetables—a good source of lutein/zeaxanthin—have a lower risk of developing AMD. In the AREDS2 trial, the people who seemed to benefit most from taking lutein/zeaxanthin were those who did not get much of these nutrients in their diet. Within this group, those who received lutein/zeaxanthin supplements had a 26 percent reduced risk of developing advanced AMD compared with those who did not receive the supplements.
What is the risk of lung cancer from taking beta-carotene?
In the AREDS2 trial, current smokers or those who had quit smoking less than a year before enrollment were excluded from receiving beta-carotene. Despite this precaution, lung cancers were observed in 2 percent of participants who took an AREDS formulation with beta-carotene, compared with 0.9 percent of participants who took AREDS without beta-carotene. Across both groups, about 91 percent of participants who developed lung cancer were former smokers.
How does lutein/zeaxanthin compare to beta-carotene?
Lutein/zeaxanthin has not been associated with increased cancer risk. Moreover, analysis from the AREDS2 trial suggests that it offers similar or better protective benefits against advanced AMD, compared with beta-carotene. In the trial, participants who took an AREDS formulation containing lutein/zeaxanthin (no beta-carotene) had an 18 percent lower risk of progressing to advanced AMD compared with those who took AREDS containing beta-carotene (no lutein/zeaxanthin).
Are there any other side effects or risks from taking the AREDS formulations?
Many older Americans take prescription medications, and a considerable number use over-the-counter drugs, dietary supplements, and herbal medicines. High-dose supplemental nutrients can sometimes interfere with medications and compete with other vital nutrients for absorption into the body. Individuals who are considering taking an AREDS formulation should discuss this with their primary care doctors and/or eye care professionals.