› What is it?
There are two different types of vitamin A. The first type, preformed vitamin A, is found in meat, poultry, fish, and dairy products. The second type, provitamin A, is found in fruits, vegetables and other plant-based products. The most common type of provitamin A in foods and dietary supplements is beta-carotene. Health benefits Scientists are studying vitamin A to understand how it affects health. Here are some examples of what this research has shown.
› Health benefits
Cancer
People who eat a lot of foods containing beta-carotene might have a lower risk of certain kinds of cancer, such as lung cancer or prostate cancer. But studies to date have not shown that vitamin A or beta-carotene supplements can help prevent cancer or lower the chances of dying from this disease. In fact, studies show that smokers who take high doses of beta-carotene supplements have an increased risk of lung cancer.
Age-Related Macular Degeneration
Age-related macular degeneration (AMD), or the loss of central vision as people age, is one of the most common causes of vision loss in older people. Among people with AMD who are at high risk of developing advanced AMD, a supplement containing antioxidants, zinc and copper with or without beta-carotene has shown promise for slowing down the rate of vision loss.
› How much do I need
The daily amount of zinc needed depends on age and gender. For women, it increases during pregnancy and when lactating. Adults age 19-plus: 900 micrograms (mcg) daily for men and 700 micrograms for women. Pregnant women: 700 micrograms; breastfeeding women: 1,300 micrograms.
Vitamin A deficiency is rare in the United States, although it is common in many developing countries. The most common symptom of vitamin A deficiency in young children and pregnant women is an eye condition called xerophthalmia. Xerophthalmia is the inability to see in low light, and it can lead to blindness if it isn’t treated.
› In food
Vitamin A is found naturally in many foods and is added to some foods, such as milk and cereal. You can get recommended amounts of vitamin A by eating a variety of foods, including the following:
• Beef liver and other organ meats (but these foods are also high in cholesterol, so limit the amount you eat).
• Some types of fish, such as salmon.
• Green leafy vegetables and other green, orange, and yellow vegetables, such as broccoli, carrots, and squash.
• Fruits, including cantaloupe, apricots, and mangos.
• Dairy products, which are among the major sources of vitamin A for Americans.
• Fortified breakfast cereals.
› Dietary supplements
Vitamin A is available in dietary supplements, usually in the form of retinyl acetate or retinyl palmitate (preformed vitamin A), beta-carotene (provitamin A), or a combination of preformed and provitamin A. Most multivitamin-mineral supplements contain vitamin A. Dietary supplements that contain only vitamin A are also available.
Source: National Institutes of Health, Office of Dietary Supplements
Please consult your health care provider before making changes to your vitamin/supplement regimen.