Drinking coffee daily combined with eating a healthy diet could cut your risk of developing age-related macular degeneration (AMD), the most common cause of blindness in seniors.

A Portuguese study found that those who followed a Mediterranean diet rich in fruits and vegetables, combined with high levels of caffeine, enjoyed a significant reduction in risk.

Researchers from the University of Coimbra University of Coimbra in Portugal studied 883 people age 55 or older between 2013 and 2015. Of those, 449 had AMD in its early stages before vision loss, and 434 did not have AMD.

When their diets were assessed they showed that people who closely follow the diet had a 35 percent lower risk compared to those who did not adhere to the diet.

Researchers used a computer program to analyze the participants' consumption of micronutrients, and found higher consumption of antioxidants such as caffeine, beta-carotene and vitamins C and E was protective against AMD.

Those who consumed more fruits had a lower risk of AMD as well as those who consumed about 78 milligrams of caffeine a day — the equivalent of one shot of espresso.

While caffeine is not considered part of the Mediterranean diet per se, consumption of caffeine-containing foods such as coffee and tea is common in Mediterranean countries.

The researchers opted to look at caffeine because it is a powerful antioxidant that is known to be protective against other conditions, such as Alzheimer's disease.

"This research adds to the evidence that a healthy, fruit-rich diet is important to health, including helping to protect against macular degeneration," said lead author Rufino Silva, M.D., Ph.D. "We also think this work is a stepping stone towards effective preventive medicine in AMD."

AMD has no cure. It affects the macula, the small spot near the center of the retina that's needed for sharp vision and allows us to see things straight ahead clearly.

More than 200,000 new cases of AMD are diagnosed in the U.S. each year and as many as 11 million people may have the disease.

Researchers at the National Eye Institute found that taking a nutritional supplement containing the following components helped slow the progression of AMD:

• 500 milligrams of vitamin C
• 400 international units of vitamin E
• 80 mg zinc as zinc oxide
• 2 mg copper as cupric oxide
• 15 mg beta-carotene, or 10 mg lutein and 2 mg zeaxanthin