The research showed that people who ate between 100 to 142 mgs of vegetable nitrates each day had a 35% lower risk of developing early AMD than people who ate less than 69mgs of vegetable nitrates each day.
Lead Researcher Associate Professor Bamini Gopinath from the Westmead Institute and the University of Sydney said the link between vegetable nitrates and macular degeneration could have important implications.
"This is the first time the effects of dietary nitrates on macular degeneration risk has been measured.
"Essentially we found that people who ate 100 to 142 mgs of vegetable nitrates every day had a reduced risk of developing early signs of macular degeneration compared with people who ate fewer nitrates.
"If our findings are confirmed, incorporating a range of foods rich in dietary nitrates - like green leafy vegetables and beetroot - could be a simple strategy to reduce the risk of early macular degeneration," Associate Professor Gopinath said.
Spinach has approximately 20mg of nitrate per 100g, while beetroot has nearly 15mg of nitrate per 100g.
The research did not show any additional benefits for people who exceeded 142mgs of dietary nitrate each day. It also did not show any significant connections between vegetable nitrates and late stage AMD, or between non-vegetable nitrates and AMD risk.
One in seven Australians over 50 have some signs of macular degeneration.
Age is the strongest known risk factor and the disease is more likely to occur after the age of 50.
There is currently no cure for the disease.
The research compiled data from the Blue Mountains Eye Study, a benchmark population-based study that started in 1992.
It is one of the world's largest epidemiology studies, measuring diet and lifestyle factors against health outcomes and a range of chronic diseases.
"Our research aims to understand why eye diseases occur, as well as the genetic and environmental conditions that may threaten vision," Associate Professor Gopinath concluded.
Bamini Gopinath, Gerald Liew, Annette Kifley, Joshua R Lewis, Catherine Bondonno, Nichole Joachim, Jonathan M Hodgson, Paul Mitchell.
Association of Dietary Nitrate Intake with the 15-Year Incidence of Age-Related Macular Degeneration.
Journal of the Academy of Nutrition and Dietetics. doi: 10.1016/j.jand.2018.07.012.