April 20, 2011 -- People who eat meat may be at increased risk of developing cataracts compared to vegetarians, a new study shows.
Researchers at the University of Oxford in England say vegetarians and vegans are 30% to 40% less likely to develop cataracts than people who eat a lot of meat.
Other factors, such as smoking, diabetes, and exposure to bright sunlight, also have been linked to greater risk of cataracts.
Researchers studied data on 27,670 people participating in the European Prospective Investigation in Cancer and Nutrition study. The participants in the study, all older than 40, were asked to fill out dietary surveys between 1993 and 1999. They were checked on between 2008 and 2009 to see if they had developed cataracts; about 1,500 had developed cataracts.
The participants were divided into groups according to the amount of meat they ate:
Highest meat consumption: 3.5 ounces or more a day.
Mid-range meat consumption: 1.7 to 3.4 ounces a day.
Low-meat consumption: less than 1.7 ounces a day.
Fish eaters: Those who ate fish but not meat.
Vegetarians: Those who did not eat meat or fish but did eat dairy products and/or eggs.
Vegans: Those who did not eat meat, fish, dairy products, or eggs.
Compared with those who ate the most meat, the risks for developing cataracts were lower for all other groups. Mid-range meat eaters had a decreased cataract risk of 4%, low-meat eaters 15%, fish eaters 21%, vegetarians 30%, and vegans 40%.
The researchers found that the progressive decrease in cataract risk was seen for both men and women but appeared to be confined to participants 65 and older at recruitment.
A cataract occurs when the eye’s lens becomes cloudy, leading to blurred vision and visual loss. Cataracts are more common in older people. Surgical procedures are typically required to treat cataracts.
The researchers say in a news release that about 21 million Americans suffer from at least one cataract, and that this number will increase to 30 million by 2020 as the baby boom generation continues to age.
The researchers write that their study is the first to describe cataract risk in relation to a vegetarian diet.
The study is published in the American Journal of Clinical Nutrition.