Intake of diet high in vitamin D and nutrients betaine and methionine helps reduce the risk of macular degeneration in twins, finds study.
Researchers at the Tufts Medical Center also concluded from a study of identical twins from the US World War II Twin Registry that the more a person smoked, higher were the risks of developing macular degeneration.
The study evaluated pairs of elderly male twins and used a survey of personal dietary and health habits to determine the variations in the occurrence of age-related macular degeneration (AMD).
AMD is highly heritable, with genetic factors determining up to 71 pc of the disease's severity, according to the researchers.
It emerged from the questionnaire filled by the twins regarding their nutritional and health behaviours that those, whose macular degeneration was at the early stages, consumed more vitamin D from dietary sources such as fish or milk than their siblings.
The study also found that the twin who was the heavier smoker tended to have more severe case of macular degeneration.
"We wanted to know why, if they have the same genes, do they have different stages of the disease?" said Johanna M. Seddon, Director of the Epidemiology and Genetics Service, Tufts Medical Center and Professor of Ophthalmology, Tufts Universtity School of Medicine.
"Eat a healthy diet with lots of fruits and vegetables, and that can make a difference - even if you have a genetic susceptibility to macular degeneration and, of course, don't smoke," he added.
Additionally, researchers also found that higher intakes of betaine and methionine were linked to a slower progression of the disease.
Whiel, betaine is found in fish, grains and spinach, methionine is present in poultry, fish and dairy foods.
The study is published in the journal Ophthalmology.