American Journal of Clinical Nutrition. Researchers at the Westmead Institute for Medical Research were examining the effect flavonoids had on age-related macular degeneration (AMD). More than 2,000 Australian adults aged 50 and over were interviewed and followed over a 15-year period. Participants were given a semiquantitative food-frequency questionnaire to determine dietary intake. The flavonoid content of foods in the questionnaire was determined by using the USDA Flavonoid Isoflavone, and Proanthocyanidin databases and macular degeneration was determined by using retinal imaging. Researchers found that people who consumed at least one serving of oranges daily had more than 60% reduced risk of developing late macular degeneration 15 years later. The data collected demonstrated that flavonoids in oranges seemed to offer protection against AMD. Benefit was even noted with only eating an orange once a week.