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Hot topic - Leafy green veg may prevent cataracts15 December 2004 - written by Bupa's Health information team Eating leafy green vegetables may help prevent cataracts, according to a new study in the December 2004 edition of the Journal of Nutrition.1 What did the study show?The study showed that substances found in leafy green vegetables helped to protect eye cells from damage by ultraviolet (UV) light. UV light is thought to be a cause of cataracts.1 What are cataracts?A cataract is a condition in which the lens of the eye clouds over. The cataract is like frosted glass, making your vision blurred.2 See below for more information about the causes, symptoms and treatment of cataracts. What is the lens?The lens is a clear tissue that is found behind the iris, the coloured part of your eye. The lens helps your eye to focus on what you are looking at.2 What do we know already about protecting the eyes?Vitamin E is thought to protect the eye from the development of diseases. Vitamin E is mainly found in plant products, such as vegetable oils, soybeans, broccoli and leafy green vegetables. It is an antioxidant.3 What are antioxidants?Antioxidants are substances that are thought to "mop up" molecules called free radicals in the body. Free radicals are produced by the body's normal chemical reactions. Free radicals are thought to damage body cells, which may lead to the development of diseases such as cancer. So mopping up free radicals may stop the damage they cause. Fruits and vegetables are good sources of antioxidants.4 Can antioxidants protect the eyes?Yes. Antioxidants help to maintain healthy cells and tissues in the eyes. Free radicals can damage the lens as well as an area at the back of the eye called the retina.5 What did this study show about antioxidants protecting the eyes?This study found that two antioxidants called lutein and zeaxanthin, as well as vitamin E, protected the eyes from UV light. Lutein and zeaxanthin are found in green vegetables such as kale (a variety of cabbage), spinach and collard greens (the leaves of kale).1 How was the study carried out?The researchers carried out experiments on human eye lens cells in a laboratory. They treated the cells with lutein, zeaxanthin or vitamin E. They exposed the treated cells, as well as some untreated cells, to UV light for ten seconds at a time. The researchers used the same amount of UV light needed to give a person a light tan.1 How did lutein and zeaxanthin affect the eyes?These antioxidants gave the eye cells double the amount of protection from UV light damage. They reduced the signs of eye damage by 50 to 60 percent. Vitamin E reduced the same signs of damage by 25 to 32 percent. Lutein and zeaxanthin were much better than vitamin E at protecting the cells from UV light damage.1 How does UV protection prevent cataracts?The sun's rays (UV light) have been linked to the development of cataracts. If the eyes are protected from UV light, then they may be less likely to develop cataracts.1,5 Should I eat more green vegetables?You should try to eat the recommended five portions of fruit and vegetables each day. A serving of green vegetables counts as one of your portions.6 This study suggests that the antioxidants - lutein and zeaxanthin - that are found in leafy green vegetables may provide your eyes with extra protection from sun damage. This protection may prevent cataracts developing.1 More research is needed to find out whether eating leafy green vegetables directly protects your eyes from UV light. What else causes a cataract?Most cataracts are caused by changes in the lens of the eye. The lens needs nutrients to stay healthy. When it does not receive enough nutrients, the lens may become cloudy. This occurs naturally as people get older.7 In younger people, cataracts can occur as effects of other conditions, such as diabetes, eye injuries or from taking certain medicines.7 Cigarette smoke has also been associated with the development of cataracts. Cigarette smoking increases the amount of free radicals in the body. The free radicals can stop the body from getting the right vitamins and minerals from food. A poor diet can damage eye tissue.5 Who is affected by cataracts?People of any age can get cataracts. Men and women are affected equally. Most cataracts develop as people get older - around the age of 50-60.7 What are the symptoms of cataracts?Symptoms of cataracts may include the following:
Symptoms gradually get worse as the cataract develops.7 Can cataracts spread?No. Cataracts cannot spread from one eye to the other, but they can develop in both eyes at the same time.7 How are cataracts treated?Mild cataracts may not be treated. As soon as your cataract interferes with your daily life and your ability to read or work, then an operation to remove the cataract is recommended. Removing a cataract is a simple operation that is normally carried out under local anaesthetic. This means that you are awake during the operation but you will not feel anything. The lens containing the cataract is removed and replaced with a plastic lens, which stays in your eye permanently. After the operation, you should be able to see clearly.2,7 Can cataracts be prevented?Cataracts that develop as a result of getting old cannot be prevented. However, you can reduce your chances of developing a cataract by wearing sunglasses that protect your eyes from UV light.7 If mothers get rubella (German measles) while they are pregnant, the baby is more likely to be born with a cataract. This is rare but can stop the baby's sight developing normally if it isn't treated early. It is important to make sure you are immunised against rubella before you become pregnant.7 For more information about rubella and preparing for pregnancy, please see our factsheet: How can I keep my eyes healthy?
Further informationBupa resources:
External resources:
References
All websites accessed on 09 December 2004
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