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I have macular degeneration, and my ophthalmologist suggested taking a dietary supplement to preserve my vision as long as possible. Is there research to back this up, and if so, which supplement should I buy?
Many dietary supplements promoted for vision or eye health are based on formulations tested in the Age-Related Eye Disease Studies (AREDS), a series of large clinical trials sponsored by the National Institutes of Health. These studies found that among people with age-related macular degeneration (AMD) who were at high risk of developing advanced AMD, supplements containing vitamin E, vitamin C, zinc, copper, and either beta-carotene or lutein plus zeaxanthin helped slow down the rate of vision loss. Adding the omega-3 fatty acids EPA and DHA to the supplements didn’t help, but it didn’t do any harm either.
The types and amounts of ingredients in commercially available eye-health supplements vary. We recommend asking your health care provider to make a recommendation. You can also see the specific formulations that were tested in the AREDS studies, along with the study results, on the National Eye Institute website.
I am taking a B-100 dietary supplement. It contains very high doses of vitamin B6, vitamin B12, and several other vitamins. Is it safe?
Many of the B vitamins—including vitamin B12, thiamin, and riboflavin—do not appear to be harmful at high doses. Therefore, scientists have not established safe upper limits for these nutrients. However, other B vitamins—including niacin and vitamin B6—do have upper limits and can cause problems if you get too much. This is particularly true for vitamin B6 which has an upper limit of 100 milligrams (mg) per day. Getting too much vitamin B6 can cause painful, unsightly skin patches, sensitivity to sunlight, nausea, and heartburn. If you take excessive amounts for a year or more, vitamin B6 can also cause nerve damage that can lead you to lose control of bodily movements. Unless your health care provider has recommended a high-dose B vitamin supplement, it’s safest to look for supplements that do not provide amounts at or above the upper limits.
Have more questions? See our fact sheet on vitamin B6 along with our other vitamin and mineral fact sheets.
I am 58 and recently read that I should get 600 IU per day of vitamin D, but I can’t find a vitamin D supplement that has less than 1,000 IU. Most have 2,000 IU or even more. Is it safe to take one of these?
Younger adults need 600 IU of vitamin D per day, and those over 70 need 800 IU. This includes what you get from foods, beverages, and dietary supplements, and is on top of any vitamin D you may get from sun exposure. Vitamin D is present in a few foods such as fatty fish (like salmon and tuna), fortified milk, beef liver, cheese, egg yolks, and mushrooms, but it can be hard to get enough. Some people have had their vitamin D levels tested and found out they are low.
Unless you are being treated by your health care provider, you shouldn’t get more than 4,000 IU per day of vitamin D. Intakes below this amount are considered safe, so taking a dietary supplement that has 1,000 IU or even 2,000 IU should be safe. But we recommend talking with your health care provider to determine whether you need to take a vitamin D dietary supplement, and if so, how much.
Have more questions? See our fact sheet on vitamin D.
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