Can vitamin supplements help maintain your vision?

Photo of an older woman taking a tablet (Brigitte Wodicka / Hemera / Thinkstock)

Dietary supplements containing beta-carotene, vitamin C or vitamin E can neither prevent age-related cataracts nor slow the progression of the condition.

Dietary supplements are often marketed using a number of health-related claims and are freely available in pharmacies, supermarkets, drug stores and on the internet. They come in many different forms, including tablets, capsules, powder or liquids. These products contain nutrients like vitamins or minerals that can also be found in everyday food products, but in a higher concentration and often at a high dose. Some of these productsare claimed to be especially beneficial for your eyes and vision.

Cataracts develop when the lens of the eye gradually becomes cloudy. This causes your vision to become increasingly blurry: Objects appear as if viewed through a veil or fog. In industrialized countries, cataracts are more common in older people.

According to one common theory, substances called free radicals develop in the cells of the eyes, where they can damage the tissue. Some vitamin supplements are believed to prevent this damage, thereby supposedly preventing cataracts from developing, or slowing down vision loss.

Studies on preventing and treating cataracts with dietary supplements

Researchers from an international research group called the Cochrane Collaboration looked into the benefits of vitamin supplements for cataracts. They looked for special studies called randomized controlled trials that compared these products either with one another or with a fake supplement (placebo). They checked whether taking supplements could prevent cataracts or slow their progression.

The researchers analyzed nine studies involving a total of almost 120,000 people between the ages of 35 and 85. The participants used products with vitamin C, vitamin E and/or beta-carotene – that is, products thought to be especially good for your eyes – for up to twelve years.

Vitamin supplements have no benefit

The results of the studies clearly showed that vitamin supplements are not effective against cataracts. People who had taken these products – in some cases for many years – developed cataracts just as often as people who had been taking a placebo. These supplements also did not slow down the progression of the cataracts and they did not have any effect on eyesight. But some products had side effects: Depending on the study, between 7 and 16 out of 100 people who took beta-carotene had their skin turn yellowish-orange. This is a sign that they had taken too much beta-carotene.

Although vitamins are important for the body, a normal, balanced diet usually provides enough vitamins. So there is no reason to take dietary supplements to try to prevent or slow down cataracts. The Cochrane researchers considered the results to be so clear that they see no need for further research in this area.