Vitamin A

Page 1 of 6

Vitamin A is essential to good vision. Vitamin A also plays a role in Alzheimer's Disease, HIV, and Inflammatory Bowel Disease (IBD). Learn about the usage, dosage, side-effects of vitamin A.

Overview

Vitamin A is very important for maintaining good vision. In fact, the first sign of a vitamin A deficiency is often night blindness. Vitamin A also contributes to the maintenance of healthy skin and mucous membranes that line the nose, sinuses, and mouth. Research has shown that this nutrient is necessary for proper immune system function, growth, bone formation, reproduction, and wound healing. Animal studies also suggest that it provides some protection from toxic chemicals such as dioxins. (Dioxins are released into the air from combustion processes such as commercial waste incineration and burning fuels like wood, coal or oil. These chemicals can also be found in cigarette smoke.)

The liver can store up to a year's supply of vitamin A. However, these stores become depleted when a person is sick or has an infection. Research suggests that parasitic infections such as intestinal worms may deplete the body's vitamin A stores and interfere with its absorption.

Vitamin A is a fat-soluble vitamin derived primarily from animal-based foods. However, the body can also make vitamin A from beta-carotene, a fat-soluble nutrient found in dark green leafy vegetables and the more brightly colored fruits and vegetables such as carrots, sweet potatoes, and cantaloupe.

Vitamin A Uses

Acne, Psoriasis, and other Skin disorders

Topical and oral preparations containing retinoids (synthetic form of vitamin A) are helpful in clearing up acne and psoriasis and have shown promise for treating other skin disorders such as rosacea, premature aging from the sun, and warts. These are given by prescription.

Eye Disorders

A number of vision disorders involving the retina and cornea are associated with vitamin A deficiencies. Night blindness, for example, and xerophthalmia (characterized by dry eyes) improve with vitamin A supplementation. A large, population-based study conducted in Australia showed that vitamin A had a protective effect against cataracts.

Wounds and Burns

The body needs vitamin A, along with several other nutrients, in order to form new tissue and skin. The body's levels of vitamin A are low immediately after burn injuries, for example. Supplementation with beta-carotene helps the body replenish vitamin A stores, strengthen the immune system, relieve oxidative stress caused by the injury, and aid the body in forming new tissue.

Immune System

Research has shown that vitamin A boosts the immune system by stimulating white blood cell function and increasing the activity of antibodies (proteins that attach to foreign proteins, microorganisms, or toxins in order to neutralize them). Vitamin A deficiency may be associated with increased risk of infection and infections tend to deplete the body's stores of vitamin A.

Vitamin A deficiency, for example, is common among children in many developing countries who are prone to infections, which often results in life-threatening diarrhea. Low levels of vitamin A are also particularly severe among children infected with the human immunodeficiency virus (HIV). Some studies suggest that vitamin A supplements may reduce the risk of death in children infected with HIV. Your doctor will determine whether vitamin A (in addition to standard treatment) is necessary and appropriate.