Eating fruit could protect against an age-related eye disease which can cause blindness, research suggests.
Researchers from the Brigham and Women's Hospital in Boston followed the progress of over 118,000 people for between 12 and 18 years.
Those who ate three or more servings of fruit a day were 36% less likely to develop age-related maculopathy than people who ate less than 1.5 per day.
The study is published in the Archives of Ophthalmology.
Age-related maculopathy, or age-related macular degeneration, is the leading cause of blindness in people over 65.
The condition is caused by the deterioration of the macula, a part of the light sensitive layer in the eye called the retina.
The cells either break down, or the tissue is damaged by the growth of blood vessels under the retina.
There is a treatment for the condition, but no cure.
Previous research has shown antioxidant vitamin and mineral supplementation protects against the condition, and that supplementation with high-doses of vitamins C and E, beta carotene and zinc delays its progress.
The researchers in this study looked at how the amount of fruit, vegetables and vitamins people ate related to their risk of developing the eye disease.
They followed 77,562 women who were part of the Nurses' Health Study and 40,866 men who were taking part in the Health Professionals Follow-up Study.
All were at least 50 years old when the study began with no diagnosis of ARM. Women were followed for up to 18 years, and men were followed for up to 12 years.
Women completed questionnaires about their diets up to five times over the follow-up period (in 1980, 1984, 1986, 1990 and 1994), and men three times, in 1986, 1990, and 1994.
They also reported their vitamin and supplement use once every two years.
Over the follow-up period, 329 women and 135 men were diagnosed with early stage ARM, and 217 women and 99 men with neovascular ARM, a more severe type of the condition.
While three or more portions of fruit a day was found to significantly cut someone's risk of developing neovascular ARM - a severe form of the disease, eating more vegetables did not appear to hold any benefit.
Bananas and oranges were strongly linked with protective benefits.
Researchers also found that levels of antioxidant vitamins or carotenoids - compounds responsible for the red, yellow and orange pigments found in some fruits and vegetables - were not directly related to ARM risk.
Food versus supplements
Writing in the journal, the researchers led by Dr Eunyoung Cho, said: "Fruit intake was inversely related to age-related maculopathy, particularly neovascular ARM, the form of this disease that frequently involves severe vision loss.
"Since none of the antioxidants or carotenoids contributed substantially, other factors may also contribute to the reduced risk."
They suggest other constituents of fruits with potential health benefit include flavanoids, fibre, folate and potassium.
Catherine Collins, a dietician based at St George's Hospital in London, said the study findings made sense because certain substances found in fruit had specific benefits for eye health.
She said the beneficial link with fruit may have been clearer in this study because people did not eat enough of lutein-rich vegetables such as spinach for them to have a noticeable effect.
She added: "There are substances in foods which give you extra benefits compared to vitamin and mineral supplements".
Source BBC News