Flavonoids found in oranges appear to help prevent against the development of develop macular, say the authors behind a new study.
Writing in the American Journal of Clinical Nutrition, the Australian research team report that people who ate at least one serving of oranges every day had more than a 60% reduced risk of developing late macular degeneration 15 years later – compared to those who did not eat oranges.
"Essentially we found that people who eat at least one serve of orange every day have a reduced risk of developing macular degeneration compared with people who never eat oranges," commented lead researcher Bamini Gopinath, an associate professor at the University of Sydney.
"Even eating an orange once a week seems to offer significant benefits,” she said. "The data shows that flavonoids found in oranges appear to help protect against the disease."
Gopinath added that while other research has linked common nutrients such as vitamins C, E and A on the eyes, the new study also looked at the relationship between flavonoids and macular degeneration.
"We examined common foods that contain flavonoids such as tea, apples, red wine and oranges.
"Significantly, the data did not show a relationship between other food sources protecting the eyes against the disease," she said.
15 year study
Researchers from the Westmead Institute for Medical 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.
The team interviewed more than 2,000 adults aged over 50 and followed them over a 15-year period.
Dietary intake was assessed by using a semi-quantitative food-frequency questionnaire (FFQ), after which estimates of the flavonoid content of foods in the FFQ were assessed by using the USDA Flavonoid, Isoflavone, and Proanthocyanidin databases.
Using cross-sectional analysis, the team found that for each 1 standard deviation (SD) increase in total overall flavonoid intake, there was an associated reduction in the likelihood of age-related macular degeneration (AMD).
“A marginally significant trend (P = 0.05) was observed between increasing the intake of total flavanone and hesperidin (from the first to the fourth quartile) and reduced likelihood of incident late AMD, after multivariable adjustment,” they reported.
Indeed, participants who reported eating one or more servings of oranges per day were found to have a 61% reduction in risk of late AMD compared with those who never consumed oranges at baseline.
“Our findings suggest an independent and protective association between dietary intake of flavonoids and the likelihood of having AMD,” concluded the team – who added that further prospective cohort studies are needed to validate the findings.
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1093/ajcn/nqy114
“Dietary flavonoids and the prevalence and 15-y incidence of age-related macular degeneration”
Authors: Bamini Gopinath, et al