Can Dietary Supplements Protect Your Eyes?

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En español | When Mary Frey Eaton, of Baton Rouge, Louisiana, was in her 60s, an ophthalmologist suggested she take flaxseed oil and later added another supplement — PreserVision AREDS — to her daily regimen. Her daughter Susan Eaton says, “Mother lived to be 91 years old and was still reading the paper every day. The majority of her 90-year-old friends had developed macular degeneration and could no longer read.”

So do vitamins and other supplements really help, or did the elder Eaton just get lucky?

It's hard to know, says Frank Siringo, M.D., O.D., a retina surgeon at Omni Eye Specialists in Denver. “There are shelves full of supplements for various eye diseases,” he notes, “but the data is just not compelling [that it can help for conditions] other than dry eye and macular degeneration.”

Here's what you should know about supplements and those two conditions.

Macular degeneration

Common in people over 50, macular degeneration blurs or reduces vision in the center of your line of sight when part of the retina becomes thin over time. The condition can affect one eye at first and then both. And it can grow worse over time, leading to irreversible blindness. Early detection with regular eye exams and treatment can delay the loss of vision, though there's no cure for age-related macular degeneration (AMD). Your risk of developing it depends on age (it's most likely to occur after age 60), race (whites are more likely to get AMD than African Americans or Hispanics) and family history.

How can you save your sight, or at least slow macular degeneration's progression? Healthy lifestyle habits that are good for your general well-being are also good for your eyes, Siringo says. “I ask patients to remember that their eyes are plugged into the rest of their body, so my dietary and lifestyle recommendations mirror that of the cardiologist or primary care physician.”

Siringo's advice: Try to adhere to a diet rich in vegetables, particularly leafy green vegetables, and consume mostly seafood sources of protein and fat. Minimize processed foods, especially overly salty or sweet carbohydrates and cured meats. Exercise regularly, and stick to the perimeter of the grocery store when shopping.

But many Americans don't eat a balanced diet. For those who don't, supplements known as AREDS2 can help protect the retina from the damage that can come with nutrient deficiencies, says Baton Rouge ophthalmologist Thomas C. Stuckey III, M.D. He thinks that AREDS2 supplements are a good idea for anyone, “but more so in people with poor diet, existing macular disease or genetic predisposition to macular disease."

AREDS, named for the 2001 “Age-Related Eye Disease Study” of 5,000 people with AMD, is a formula for supplements that includes high doses of zinc and antioxidants that showed evidence of slowing the disease in those with advanced AMD in only one eye or intermediate AMD in both. The original formula contains vitamins C, E, zinc and beta-carotene (a plant pigment the body uses to make vitamin A).

In smokers and those who had recently quit smoking, however, beta-carotene increased the risk of lung cancer. A new formula, AREDS2, replaced beta-carotene with lutein and zeaxanthin in a study published in 2012 in Opthalmology. Also made by plants, these substances are found in green leafy vegetables like kale, turnip greens and broccoli; they're also found in the eye, where they are believed to help absorb damaging light. Subjects who took the AREDS2 formula showed no higher incidence of lung cancer.

Dry eye

Dry eye, which affects approximately 14 percent of adults in the U.S., occurs when the film that coats the surface of the eyes is insufficient, making the eyes feel dry and causing discomfort and, sometimes, blurred vision. For years ophthalmologists have recommended omega-3 and omega-6 essential fatty acids in the form of fish oil or flaxseed oil to improve symptoms of dry eye; there has been some debate over which form or combination is most effective.

The good news: A 2019 meta-analysis, published in the respected journal Cornea, reviewed 17 randomized placebo-controlled clinical trials of omega-3 supplementation that included more than 3,000 patients and found statistically significant improvement in patient symptoms as well as objective clinical measures of dry eye disease.

Choosing which of the many brands of omega-3 supplement to buy is the hard part. “Different formulation and processing methods are promoted as superior to others by the companies that manufacture them, but no definitive consensus exists,” says Stuckey, who suggests starting with any omega fatty acid product you prefer and seeing if it helps. If it doesn't, talk with your doctor about other options. If your dry eye is serious, you may want to try other treatments, such as prescription eye drops.

Common drug interactions and side effects

If you decide to try an omega-3 supplement for dry eye, keep in mind that these can also act as a mild blood thinner. “Patients already taking blood thinners should discuss with the doctor that prescribed them prior to starting one of these supplements,” Siringo says.

And for those taking AREDS2, this formula is not a substitute for a multivitamin, so if you take one, continue to do so. Similarly, a multivitamin alone cannot provide the same vision benefits to people with macular degeneration as AREDS and AREDS2, which offer much higher dosages of relevant vitamins and minerals.

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