What is Vitamin A?

Vitamin A is a fat-soluble antioxidant that protects your cells against damaging free radicals and plays other vital roles in the body. However, it is potentially more dangerous than most other vitamins because it can build up to toxic levels. For this reason, it should be used with caution.

It has long been assumed that beta-carotene supplements taken at nutritional doses are a safer way to get the vitamin A you need. However, while this may be true in general, beta-carotene also appears to present some risks. See the full Beta-Carotene article for more information.

There is some evidence that vitamin A supplements reduce deaths from measles and other infectious illnesses among children in developing countries, ¹ presumably because they correct a deficiency in the children's diets. This doesn't mean that vitamin A supplements above and beyond the basic nutritional requirement are a useful treatment for measles or any other childhood disease.

Vitamin A might improve blood sugar control in people with diabetes . Unfortunately, people with diabetes may also be especially vulnerable to liver damage from excessive amounts of vitamin A (see Safety Issues ). Therefore, if you have diabetes, you should take vitamin A only on the advice of a physician.

Vitamin A has shown some potential for preventing one type of skin cancer (squamous cell...

Safety Issues

The safe upper intake levels of vitamin A have been set as follows: ²

• Infants

• 0-12 months: 600 mcg RAE or 2,000 IU

• Children

• 1-3 years: 600 mcg RAE or 2,000 IU

• 4-8 years: 900 mcg RAE or 3,000 IU

• Males and Females

• 9-13 years: 1,700 mcg RAE or 5,660 IUs

• 14-18 years: 2,800 mcg RAE or 9,320 IUs

• 19 years and older: 3,000 mcg RAE or 10,000 IU

• Pregnant Women

• 18 years old or younger: 2,800 mcg RAE or 9,320 IU

• 19 years and older: 3,000 mcg RAE or 10,000 IU

• Nursing Women

• 18 years old or younger: 2,800 mcg RAE or 9,320 IU

• 19 years and older: 3,000 mcg RAE or 10,000 IU

It is thought that dosages of vitamin A above 50,000 IU per day taken for several years can cause liver...