As you age, the natural lens that sits inside your eye might gradually harden and turn cloudy, a condition known as a cataract. Lifestyle factors and nutrition can hasten or slow down this natural process that can lead to vision loss. Surgical removal is the only known treatment, and this makes prevention a key player in reducing the growth of cataracts. Knowing if nutrient deficiencies such as low vitamin D intake can affect cataracts will help you make good nutritional choices for your eyes.
Formation
Your lens sits just behind your iris, the colored part of your eye. This round disc consists of proteins and water, providing a clear pathway for light to pass through and reflect onto the back of the eye for clear vision. In the early stages of cataract formation, the proteins in the lens begin to break down and clump together. This starts to turn the lens slightly hard and cloudy, so that light scatters as it hits the lens, causing glare and gradually destroying any clear images.
Vitamin D
Vitamin D plays crucial roles in bone strength, cell growth, and the function of your muscles and immune system. If you do not have adequate intake of vitamin D, you have a greater risk for serious conditions such as weak bones. As of 2011, low vitamin D intake is not clearly linked to the development of cataracts.
However, in a 1988 study conducted by researchers at Tufts University, findings showed that people who had good vitamin D levels, as well as good levels of other nutrients, had a reduced risk for cataracts that form around the edge of the natural lens. This shows a possible link, but the study did not evaluate vitamin D levels alone. As such, the high levels of other beneficial nutrients could have played more of a role in preventing cataract formation.
Intake
To ensure that you have a good intake of vitamin D, the average adult needs between 600 and 800 International Units, or IU, each day. Age, health and other factors play a role in the intake you need, and your doctor can help you determine the amount appropriate for you.
Sunlight provides vitamin D, but this increases your risk for damage from ultraviolet rays. Vitamin supplements can provide vitamin D, or you can eat vitamin D-rich foods. A 3 oz. serving of salmon contains 447 IU of vitamin D, and one large egg provides 41 IU. Other food sources include tuna, liver, yogurt, milk, cheese and cod liver oil.
Considerations
If you think you might not have a good intake of vitamin D, talk with your doctor. She can recommend tests to see if you have a deficiency. You should also discuss ways to prevent or slow down the growth of cataracts. Nutrients such as vitamin C, vitamin E and lutein might have some benefits, and if your doctor thinks these nutrients might benefit you, she can help you determine the amount you should take each day.
References
- MayoClinic.com; "Cataracts"; May 2010
- Office of Dietary Supplements: National Institutes of Health -- Vitamin D
- American Optometric Association: Nutrition and Cataracts
- "American Journal of Clinical Nutrition"; "Nutritional Status of Persons With and Without Senile Cataract: Blood Vitamin and Mineral Levels"; P. F. Jacques et al.; July 1988
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