Age-Related Macular Degeneration, Nutritional Supplements and Diet
Age-related macular degeneration (AMD) is the leading cause of severe visual impairment among people over the age of 60.
The exact cause of AMD is not fully understood, although the body’s normal metabolism and processes of tissue “oxidation” may play a key role. Therapeutic supplementation with “antioxidant” nutrients has been - and continues to be - investigated as a potential means of slowing the progression of disease, as there is no known cure for AMD.
The Age-Related Eye Disease Study
The first study to conclusively demonstrate a benefit of dietary supplements was the Age Related Eye Disease Study (AREDS), published in 2001 and sponsored by the National Eye Institute (NEI), a division of the National Institute of Health.
This study found that people at risk of developing advanced stages of AMD lowered their risk by approximately 25% when treated with a high-dose combination of vitamin C (500mg), vitamin E (400 IU), beta-carotene, a water-soluble precursor to vitamin A, (15mg), zinc (80 mg), and cupric oxide (2mg). For those who had either no AMD or very mild AMD, the supplements were of no apparent benefit.
The Age-Related Eye Disease Study 2
The NEI designed the AREDS 2 study, published in May 2013, to determine whether the addition of other antioxidants (lutein/zeaxanthin and/or omega-3 fatty acids) to the original AREDs formula provided further benefits to reducing the development of advanced AMD.
AREDS 2 also studied whether beta carotene, which is contraindicated in smokers given a higher risk of developing lung cancer, could be eliminated from the supplement.
The main results of AREDS 2 showed that (1) replacing beta carotene with lutein/zeaxanthin reduced the progression of advanced AMD, (2) beta carotene leads to decreased absorption of lutein/zeaxanthin into the body if taken together, (3) beta carotene had an increased risk of lung cancer in former smokers, (4) omega-3 fatty acids did not show added benefit.
The newest formula based on the results of AREDS 2 contains the following:
Who should take supplements for AMD?
Only those people who are at risk for developing advanced AMD should take the AREDS 2 supplement. There is also no proof that dietary supplements will prevent macular degeneration in people without any preexisting disease or only mild dry AMD. Therefore, we do not currently recommend such high dose vitamin supplements in people without established “dry” macular degeneration of at least moderate severity in one or both eyes.
Will AREDS 2 vitamin supplements cure my AMD?
No. It is important to remember that AREDS 2 supplements are not a cure for macular degeneration. They will not restore vision that has already been lost, nor will they completely arrest the progression of disease.
Should I switch to AREDS 2 formula if I am on the original AREDS?
Yes. AREDS 2 showed added benefit of replacing beta carotene with lutein/zeaxanthin. Also, taking lutein/zeaxanthin does not have the increased risk of lung cancer in former or current smokers that beta carotene has.
Can I take the original AREDS formula and add lutein/zeaxanthin, instead of switching to the AREDS 2 formula?
No. AREDS 2 showed that if taken together, beta carotene reduced the absorption of lutein/zeaxanthin. Since beta carotene, lutein, and zeaxanthin are all in the family of plant-based nutrients called “carotenoids”, and there is more benefit for your AMD and less risk of cancer development by replacing beta carotene with lutein/zeaxanthin, only lutein/zeaxanthin is recommended.
Do I need to take omega-3 fatty acids as well?
While the AREDS 2 did not show any added benefit of adding omega-3 fatty acids to the new formula, the study concluded that observational data supports the recommendation of eating a healthy diet, especially one containing foods rich in omega-3 fatty acids, such as fish.
Can I just eat a healthy diet and get the same nutrition as AREDS 2 supplement?
No. The levels of vitamins in the AREDS 2 supplement are very difficult to attain from diet alone, and supplements are recommended to receive the risk reduction achieved in the study. However, eating a healthy diet, especially rich in green-leafy vegetables and fish containing omega-3 fatty acids, is still recommended.
Can I still take a daily multivitamin if I am taking the AREDS 2 supplement?
Yes. The AREDS 2 supplement does not provide the same array of nutrients and minerals that are in a daily multivitamin. Most people in the AREDS studies were on multivitamins. It is recommended that you discuss all supplements that you are considering taking with your primary care physician.
Can I take a multivitamin instead of the AREDS 2 formula?
No. While a multivitamin has many nutrients and minerals, it does not contain the high levels of specific vitamins studied.
Which vitamin supplement is recommended for smokers?
The AREDS 2 formula is now recommended for all patients, including current and former smokers, as the beta carotene has been eliminated from the recommended formula. Beta carotene may increase lung cancer risk, but lutein/zeaxanthin has not been shown to be associated with increased risk of cancer.
Which brand of supplement should I take?
There are many available brands for AREDS 2 supplements. All are available over-the-counter and without a prescription. The recommended formula is the AREDS 2 formula, as above. There is no proof that any one brand is superior to another, nor do we have any financial interest in any of these products. Many brands will have doses that are not exactly the same as the AREDS 2 formula, and some brands will have additional vitamins or minerals, such as omega-3 fatty acids. Available brands include Ocuvite Preservision AREDS 2 or I-CAPS.
Alternative nutritional supplements are also widely available and promoted as beneficial for eye health, but their effectiveness has not been proven by scientific studies.
The bottom line: Since no formula other than that used in AREDS, and now AREDS 2, has been shown to provide benefit in large clinical trial studies, we do not know if alternative supplements are more, less, or equally effective.
Is there any harm to taking the AREDS vitamins?
The long-term effects of taking large doses of these supplements are still unknown. However, over a 5 to 10 year period, AREDS and AREDS 2 showed very few side effects from such supplements. In AREDS, there was a slight increased risk for urinary tract problems, and some people experienced mild yellowing of the skin.
Vitamin manufacturing and marketing is an unregulated industry, so there is a potential for variability among products. Finally, it is very important to inform your primary care physician before taking any high dose supplements and to follow dosage recommendations carefully.
The levels of antioxidants and zinc utilized in AREDS 2 is equal to 5 to 13 times the recommended daily allowance (RDA), levels that cannot typically be obtained through diet alone. If recommended for you, AREDS 2 dose supplements should be considered just that - a supplement to a healthy, balanced diet, not a substitute for proper nutrition.
There are numerous antioxidants and other nutrients in a balanced diet that may be important for your eyes or for your general health. For example, several epidemiological studies have suggested a lower likelihood of macular degeneration in people who consume many dark green leafy vegetables as well other richly pigmented vegetables and fruits (such as spinach, kale, broccoli, corn, squash, grapes, peaches and oranges). Some studies have also suggested that saturated and trans-saturated fats may be harmful (such as in meat, dairy products, and fried foods), while omega-3 poly-unsaturated fatty acid (such as found in certain nuts and fish oil) may be protective of macular degeneration. In all of these epidemiological studies, cause and effect is not yet firmly established.