Dear Doctor: Do "eye vitamins" have any benefit at all? I know a lot of seniors who believe in them, but I'm skeptical.
Dear Reader: Skepticism should be a marker for overall health, especially with the flood of vitamins sold in vitamin shops, grocery stores and pharmacies. Vitamin supplements have been touted for nearly every condition with scant evidence of their efficacy when compared with a healthy diet.
Lutein and zeaxanthin generally top the list of "eye vitamins." That's because these dietary carotenoids -- related to beta carotene and vitamin A -- help form retinal macular pigment. This pigment absorbs damaging light rays and thus protects the macula, the part of the retina responsible for detailed vision. Additionally, these carotenoids are antioxidants, protecting the eye from cellular damage.
Now let's examine the evidence. Diets high in lutein and zeaxanthin have been associated with a lower risk of the late changes of macular degeneration. And, in a review of eight studies, higher blood levels of lutein and zeaxanthin were linked to a decreased cataract risk. Leafy green vegetables such as lettuce, spinach, kale and parsley are high in these carotenoids, as are eggs, so a diet containing these foods may help protect your vision.
But taking a vitamin? In people who already have macular degeneration, antioxidants such as vitamin C, vitamin E, lutein and zeaxanthin do seem to slow the progression of macular degeneration. In fact, these antioxidants -- when taken with zinc -- are linked to a 28 percent reduction in late macular degeneration. People who substituted beta carotene for lutein and zeaxanthin reported similar benefits. Note, however, that beta carotene has been associated with increased lung cancer rates in people who smoke.
That's not to say that antioxidants lower the chances of developing the disease in the first place. A 2017 review of five studies assessed the impact on 55,614 people without macular degeneration who took antioxidants from four to 10 years. The authors found that neither vitamin E, vitamin C nor beta carotene decreased the rate of macular degeneration compared with a placebo. In fact, vitamin E was associated with a slight increase in the rate of late macular degeneration.
As for multivitamins, one of the studies assessed the potential effects of the multivitamin Centrum Silver and found a 22 percent relative increased rate of macular degeneration compared with a placebo.
As for non-antioxidant vitamins, a 2009 study did show a decreased rate of AMD with higher doses of B vitamins (specifically B12, B6 and folic acid). The study included 5,442 female health care professionals who had either risk factors for coronary artery disease or actual cardiovascular disease and who took B vitamins. After an average follow-up time of 7.3 years, women who took the B vitamins had a 34 percent decreased risk of macular degeneration. Increased dietary intake of B12, B2 and B3 also has been associated with a decreased rate of cataracts.
My recommendation is to get most of these so-called "eye vitamins" from your diet. If you have risk factors for heart disease, you may find benefit with B vitamins, or if you have macular degeneration, you may benefit from antioxidant vitamins. But that's as far as the science on "eye vitamins" goes.
(Send your questions to firstname.lastname@example.org, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)