Age-Related Eye Disease Study--Results
Q. Who should take the combination of antioxidants and zinc like those used in the Age-Related Eye Disease Study?
People who should consider taking the combination of antioxidants plus zinc include those who are at high risk for developing advanced AMD. These people are defined as having either:
- Intermediate AMD in one or both eyes. Intermediate AMD is defined as the presence of either many medium-sized drusen or one or more large drusen.
- Advanced AMD in one eye, but not the other eye. Advanced AMD is defined as either a breakdown of light-sensitive cells and supporting tissue in the central retinal area (advanced dry form), or the development of abnormal and fragile blood vessels under the retina (wet form) that can leak fluid or bleed. Either of these forms of advanced AMD can cause vision loss.
Q. How do I know if I have AMD and the stage it is in?
Your eye care professional can tell you if you have AMD -- and its level of development -- through an eye exam in which drops are placed in the eyes to dilate the pupils. This allows for a careful examination of the inside of the eye.
Q. I am already taking daily vitamins. Should I stop taking these vitamins if I am advised to take the combination of antioxidants plus zinc evaluated by the Age-Related Eye Disease Study?
People with intermediate AMD in one or both eyes, or those with advanced AMD in one eye only, and who are advised to take a formulation like those used in the AREDS, should review the supplements they are taking with their primary care doctors and/or eye care professionals. In addition to their study medication, most of the participants in the AREDS took a multivitamin that contained the approximate recommended dietary allowance of most vitamins and minerals.
Q. How do people obtain the formulation in the dosages used by the AREDS researchers? Will it be available in tablet form in drug stores?
Bausch & Lomb, an eye care company, was a collaborator in the AREDS and provided the study formulation. The company will market the formulation used in the AREDS; other companies will probably provide similar formulations. Antioxidant vitamins and zinc can also be purchased separately; however, consumers should discuss the use of these high levels of vitamins and minerals with their doctors, and be certain to include copper whenever taking high levels of zinc.
Q. Will the formulation come in three forms: "antioxidants plus zinc," "zinc alone," and "antioxidants alone?" How will I know what to take?
Bausch & Lomb will market only the "antioxidants plus zinc" formulation. Those who are advised by their primary care doctors to take the AREDS' "zinc alone" or "antioxidant alone" formulations, as well as those who choose to purchase the "antioxidants plus zinc" formulation from another manufacturer, should compare the labels of those products with the AREDS formulations. Antioxidant and zinc formulations can also be purchased separately; however, consumers should discuss the use of these high levels of vitamins and minerals with their doctors, and be certain to include copper whenever taking high levels of zinc. Your primary care doctor can help you determine which formulation and dose is best for you.
Q. Are there reasons older people, in particular, should be cautious in supplementing their diets with the nutrients and doses used in the AREDS?
Yes. There are reasons to be cautious in using high-dose vitamins and minerals, particularly among older people. Many older Americans take prescription medications, and a considerable number use over-the-counter drugs, dietary supplements, and herbal medicines. High-dose nutrients can interfere with medications and interact with other nutrients to decrease the nutrients' absorption into the body. This can ultimately affect a person's nutritional and health status. For example, the zinc concentration in the AREDS formulation is at a very high dose and could cause copper deficiency anemia. To prevent this, copper was added to the AREDS formulation. People who are being treated for chronic diseases such as cancer, heart disease, and diabetes should not take high dose nutrients without talking with their doctors. Generally, self-medication with high doses of vitamins and minerals -- such as those in the AREDS formulation -- is not recommended. Individuals who are considering taking the AREDS formulation should discuss this with their primary care doctors and/or eye care professionals. They can help you determine which formulation and dosages are best for you.
Q. If I have been diagnosed with early AMD, should I take the nutrients to help prevent disease progression to the intermediate stage?
There is no apparent need for those diagnosed with early AMD to take the nutrients studied in the AREDS. This is because the study did not demonstrate that the nutrients provided a benefit to those with early AMD. Many people with early AMD progressed to intermediate AMD during the study, and the AREDS formulation did not seem to slow this progression. However, if you have early AMD, a dilated eye examination every year can help determine whether the disease is progressing.
Q. How long will I have to take the nutrients?
There is no specific recommendation for how long you should take the AREDS formulation. However, AREDS researchers have followed participants for at least 10 years and a treatment benefit continues. In addition, side effects have been minimal
Q. What are the side effects from the AREDS formulation?
The AREDS participants reported few side effects from the treatments. About 7.5 percent of participants assigned to the zinc treatments -- regardless of whether they were the "antioxidants plus zinc" or "zinc alone" treatment -- experienced genitourinary problems that required hospitalization. Some of these problems included urinary tract infections, kidney stones, incontinence, and enlarged prostate. This compares with five percent of participants who did not have zinc in their assigned treatment that experienced the same genitourinary problems. Participants in the two groups that took zinc also reported anemia at a slightly higher rate; however, testing of all patients for this disorder showed no difference among treatment groups. Yellowing of the skin, a well-known side effect of large doses of beta-carotene, was reported slightly more often by participants taking antioxidants.
Q. What about other antioxidants such as bilberry and lutein?
The AREDS did not study bilberry, lutein, or other antioxidants, so we don't know how they may affect eye disease. However, the Age-Related Eye Disease Study 2 (AREDS2) was launched in 2006. The AREDS2 added lutein and zeaxanthin and the omega-3 fatty acids DHA and EPA to the original study formulation. The main objective of AREDS2 is to determine if these nutrients will decrease a person's risk of progression to advanced AMD. Results from the AREDS2 are expected in 2013.
Q. Are former smokers at an increased risk for developing lung cancer if they take high doses of beta-carotene?
Large clinical trials sponsored by the National Cancer Institute demonstrated that beta-carotene increases the risk of lung cancer in current smokers. In these trials, most of these smokers were heavy smokers. The only other large clinical trial evaluating beta-carotene was the Physicians Health Study (PHS). In the PHS, there was no evidence of increased cancer risk in those randomly assigned to beta-carotene, but few physicians were active smokers. There also was no evidence of an increased risk of lung cancer in former smokers. However, many studies suggest that former smokers maintain some increased risk of lung cancer for years after stopping smoking. Therefore, it is reasonable to expect that beta-carotene may also slightly increase their risk of cancer, at least for a period of several years.
In deciding whether to include beta-carotene in a formulation designed to slow the development of advanced AMD, you and your doctor should balance the apparent increase in the risk of lung cancer associated with beta-carotene with the risk of AMD progression.
Q. Will taking high dose vitamin E in the AREDS formulation increase my risk of prostate cancer?
The long-term follow-up from The Selenium and Vitamin E Cancer Prevention Trial (SELECT) was published in October 16, 2011 edition of The Journal of the American Medical Association. The study found that taking high dose vitamin E supplements (400 IUs daily) significantly increased the risk of prostate cancer among healthy men when compared with healthy men taking a placebo (a sugar pill). The researchers found that the increased risk means that there will be 1 to 2 more prostate cancers per 1000 patients who took the high dose vitamin E for one year. Interestingly, in men who received both vitamin E and selenium, there was no increased rate of prostate cancer.
These findings from SELECT should be reviewed in the context of prior clinical trials results. Men participating in the Alpha-Tocopherol, Beta Carotene (ATBC) trial who took 50 mg of vitamin E daily had a 35 percent reduction in the risk of prostate cancer. The Physicians Health Study II (PHS II) tested 400 IUs of vitamin E every other day and found no effect on the incident of prostate cancer.
The daily dose of vitamin E in SELECT is the same as in the Age-Related Eye Disease Study (AREDS) formulation (400 IUs daily). However, AREDS study participants who received vitamin E also received other antioxidants (vitamin C and beta carotene with or without zinc). NEI researchers have conducted an analysis of the AREDS data. The AREDS formulation did not have an effect on the rate of prostate cancer in men participating in the study.
The AREDS formulation is given also in the Age-Related Eye Disease Study 2 (AREDS2), a study that is designed to test other supplements, lutein and zeaxanthin and the omega-3 fatty acids, DHA and EPA for the treatment of age-related macular degeneration. The group of independent researchers who monitors the current AREDS2 for safety has not noted any concerns in increased risk prostate cancer. All the AREDS2 study participants will be continuing to take the AREDS formulation that contains vitamin E in this study.
Although the SELECT study has demonstrated a slight increase in prostate cancer with supplementation with vitamin E, it is important to understand that not all clinical trials have found the same results. You are encouraged to speak with your health care professional about these results and your risk for vision loss or prostate cancer.
Revised: November 2011