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New Australian study reveals key role of zinc and antioxidants in preventing age-related macular degeneration
October 2007
A new Australian study has confirmed the protective influences of zinc and antioxidants against the most common cause of irreversible vision loss in Australia, age-related macular degeneration.
Affecting one in seven Australians over 50, age-related macular degeneration (AMD) has no cure and little effective treatment. The findings of this new 10 year study, available online in Ophthalmology, the journal of the American Academy of Ophthalmology, have shown that people who consume a diet high in lutein and zeaxanthin, or zinc are less likely to develop this disorder.
Known as the Blue Mountain Eye Study, the study assessed the eye health of more than 3,500 Australians aged 49 and over across 10 years, measuring the affects of zinc from daily food and supplements and other antioxidants on the long term risk of developing AMD. According to the study by Dr Jennifer Tan and the team at the Centre for Vision Research, University of Sydney, the results showed that participants with a daily zinc intake of 15.8mg or more were significantly less likely to develop early, or any AMD, compared to the rest of the population. Similar protective association was found for lutein and zeaxanthin, which are carotenoids found in vegetables and fruit, such as green beans, silverbeet, broccoli.
Macular degeneration affects the central part of the retina at the back of the eye, which is responsible for central vision. “The onset of AMD can often go unnoticed until the advanced stages when vision becomes impaired. In the most severe cases, the patient cannot read, write, or recognise faces. Given there is no cure, the more we can learn about preventative measures the better,” said Professor Paul Mitchell, Director of the Centre for Vision Research.
A necessary element for sustaining life, zinc is also essential for growth, wound healing and maintaining the body’s immune system. It is found naturally in a variety of fresh foods including lean red meat, seafood, wholegrains, nuts and legumes. “We found that red meat was the highest contributor of dietary zinc, providing more than twice the amount of zinc than that provided by vegetables, dairy and breads and cereals,” Dr Flood, nutritional epidemiologist at the Centre for Vision Research, reported. “In addition, we know that zinc from meat is more readily absorbed than that from other sources,” she added.
“Age-related macular degeneration is the leading cause of blindness in Australia, responsible for approximately two-thirds of the blindness in people aged over 50 years. Consuming a balanced diet of foods which are rich in zinc and antioxidants, with plenty of fresh fruit and vegetables is likely to be of benefit to older persons who are at a risk of AMD. ” Dr Flood emphasised.