Vegetarian diet linked to lower cataract risk

NEW YORK (Reuters Health) - Eating less meat and more vegetables is tied to a lower risk of cataracts, a British study says.

A shopper looks at organic vegetables as she pushes a shopping trolley down an aisle at a supermarket in Charenton near Paris April 6, 2011. REUTERS/Charles Platiau

In a large dietary survey that followed people for as long as 15 years, researchers found that about three in 50 meat eaters had cataracts, compared to about two in 50 vegans and vegetarians.

The results translated to a 30 to 40 percent lower cataract risk among vegetarians and vegans compared with the biggest meat eaters.

“People who don’t eat meat have a significantly lower risk of developing cataracts,” said Naomi Allen, an epidemiologist at the UK’s University of Oxford who coauthored the study.

A cataract occurs when the lens of the eye becomes cloudy, blurring vision. They’re more common in older people, and more than half of Americans either have cataracts by the time they’re 80 or have had surgery for them, according to the National Eye Institute.

The British findings do not mean that people should necessarily become vegetarians to avoid getting cataracts, Allen told Reuters Health.

The study does not prove that eating meat promotes cataracts. Eating a lot of vegetables might be protective, for instance - some past research has linked certain nutrients in plant foods to a lowered risk of cataracts. A vegetarian diet may also simply be a sign of other healthy behaviors that contribute to the lowered risk.

Smoking, diabetes, and exposure to bright sunlight are also linked to an increased risk for cataracts.

The new findings actually contradict a study done in India, where a vegetarian diet was associated with high numbers of cataracts, said Dr. Jack Dodick, who chairs the department of ophthalmology at New York University Langone Medical Center.

“It means that still to this day we don’t know what influences cataracts. It may be more lifestyle. There may be other factors in causing cataract other than diet,” Dodick, who did not work on the current study, told Reuters Health.

The British researchers asked more than 27,600 people older than 40 to fill out dietary surveys between 1993 and 1999, then monitored the participants’ medical records between 2008 and 2009 to see if they developed cataracts. Almost 1,500 had cataracts during the follow-up period.

The highest risk was seen among the heaviest meat-eaters - those who consumed more than 100 grams (3.5 ounces) of meat daily. Moderate meat eaters were only slightly less likely to develop cataracts. Fish eaters’ risk was 15 percent lower than that of the heavy meat eaters, vegetarians’ 30 percent lower and vegans’ 40 percent lower.

This study, published in the American Journal of Clinical Nutrition, was well done, Dodick said, but there are “still a lot of questions that need to be answered.”

Whether nutrition really plays a role in cataract risk is still not clear cut, he said.

It’s generally accepted that if you live long enough everyone will develop a cataract, Dodick added.

Cataracts are treated by surgery. Operations typically performed in the U.S. can cost between $1,500 and $3,000.

“It’s the most performed operation in the U.S.,” Dodick said. “Approximately 3.5 million cataract surgeries are performed a year.”

To decrease the probability of early onset cataracts, “the top of my list would be always protect eyes against ultraviolet rays when outdoors (by wearing sunglasses),” Dodick said.

“The moral of the story is, live life in moderation,” Dodick added. “A healthy active lifestyle with exercise might decrease the risk of cataracts.”

SOURCE: The American Journal of Clinical Nutrition, online March 23, 2011.