Too Much Zinc Linked to Blinding Eye Disease

By Kate McHugh, Ivanhoe Health Correspondent

ORLANDO, Fla. (Ivanhoe Newswire) -- Zinc may be behind the development of a potentially blinding eye disease. Large amounts of the mineral zinc were present in patients with age-related macular degeneration (AMD), prompting researchers to suggest a link between the mineral and the disease.

AMD is the primary cause of blindness in the elderly in Western society, and approximately 13 million Americans suffer from the disease. Zinc supplements are widely given to patients to help boost weak immune systems, so study authors fear these findings may show the supplements are doing more harm than good.

“One of the concerns that I have is that people are in a sense self supplementing,” study author Jane Flinn, Ph.D., professor of psychology at George Mason University in Fairfax, Va. told Ivanhoe.

The recommended daily allowance of zinc for an adult is 11 milligrams for men and 8 milligrams for women. Zinc supports normal growth and development during pregnancy, so doctors recommend pregnant women get 11 milligrams of the mineral everyday and 12 milligrams while lactating.

“You need to be very careful if you’re taking multiple supplements of zinc because of course, you’re also getting zinc in your diet,” Dr. Flinn said. The mineral is found in animal cells, so virtually every animal product is a food source. Oysters contain the highest levels of zinc per serving, followed by med meat and poultry.

Dr. Flinn cautions vegetarians may be the only ones not getting an adequate amount of zinc in their diet. Otherwise, excessive levels of the mineral may be dangerous to your health. “I guess it’s the usual story that too little is bad, but too much may also be bad,” Dr. Flinn said.

The research team says further research needs to be done to find a more conclusive relationship between zinc and AMD development. But they say you should talk to your doctor to determine if you are getting healthy levels of zinc in your diet before you start taking supplements or reduce the mineral from your diet.

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 Flinn, Ph.D.; Experimental Eye Research, 2007;84,772-780