Could Fish and Vitamin D Prevent Macular Degeneration?

By Betsy Lievense, Ivanhoe Health Correspondent

ORLANDO, Fla. (Ivanhoe Newswire) -- Want to preserve your eyesight? Go fish! A recent study reveals eating fish rich in omega-3 fatty acids may reduce a person's risk for age-related macular degeneration (AMD), the most common cause of blindness in people older than age 50.

Age-related macular degeneration is a disease that occurs when the macula, located just behind the retina, thins out and begins to deteriorate. AMD strikes more than 7 million Americans each year and usually results in the loss of central vision, making it difficult for patients to perceive fine details that are necessary to read or recognize familiar faces. Symptoms of AMD include blurred or distorted vision, areas of missing vision, slow recovery of vision when exposed to bright light, and difficulty differentiating between contrasting colors.

There is no proven way to prevent AMD, but researchers believe proper nutrition could help. When members of the Age-Related Eye Disease Study Research Group looked at the eating habits of 4,519 individuals between 60 and 80 years old, they found those who ate foods rich in omega-3 fatty acids (like fish) were less likely to develop advanced AMD than those who did not. In fact, participants who were at the lowest risk for AMD ate more than two 4-ounce servings of fish per week. Researchers report the DHA found in omega-3 fatty acids may stave off diseases like AMD by turning certain genes in the retina on or off. Omega-3 fatty acids might also form compounds that encourage cell survival and enhance blood vessel function, thereby reducing inflammation while maintaining a proper energy balance.

Although nutritious, experts say some fish contain high levels of mercury that could be hazardous to a patient's health. "There's always a risk of high mercury levels in fish oil products, and if you don't know the product vendor, it may be a wiser decision to eat fatty fish three times a week that has lower levels of mercury," Jane Sadler, M.D., a family practitioner at Baylor Family Medicine in Garland, TX, told Ivanhoe. "It's always better to get your intake of vitamins and supplements from eating, from your diet, than it is from a supplement."

If patients must take supplements to get the recommended amounts of DHA and omega-3 fatty acids, Dr. Sadler recommends looking for mercury-free products. "There are some fish oils available, such as Ultra Pure Fish Oil, which are purified to remove mercury. It's a premium DHA-rich supplement, and that is a good one."

Omega-3 fatty acids filled with DHA aren't the only nutrients that help prevent AMD. Researchers at the University of Wisconsin-Madison report taking Vitamin D may help stave off early (but not late) forms of AMD. Study authors looked at 7,752 individuals who were part of the National Health and Nutrition Examination Survey and concluded that Vitamin D may reduce the risk for AMD by cutting down on inflammation or preventing blood vessel growth in the retina.

No matter what form of AMD prevention people choose, Dr. Sadler said the bottom line is people need to take on healthier lifestyles.

This article was reported by Ivanhoe.com, which offers Medical Alerts by e-mail every day of the week. To subscribe, click on: http://www.ivanhoe.com/newsalert/.

SOURCE: Ivanhoe interview with Jane Sadler, M.D.; Archives of Ophthalmology, printed online May 14, 2007