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Vitamin A Deficiency

By

Larry E. Johnson

, MD, PhD, University of Arkansas for Medical Sciences

Last full review/revision Nov 2020| Content last modified Nov 2020
Click here for the Professional Version

Vitamin A deficiency can result from a diet low in vitamin A or an absorption or liver disorder.

  • Night blindness is an early symptom.

  • Blindness can eventually develop.

  • The eyes, skin, and other tissues become dry and damaged, and infections develop more often.

  • The diagnosis is based on symptoms and blood tests.

  • Taking high doses of vitamin A for several days corrects the deficiency.

Vitamin A (retinol) is necessary for the function of light-sensitive nerve cells (photoreceptors) in the eye’s retina and thus helps maintain night vision. It also helps keep the skin and the lining of the lungs, intestine, and urinary tract healthy and protects against infections. Good sources of vitamin A include fish liver oils, liver, egg yolks, butter, cream, and fortified milk. (See also Overview of Vitamins Overview of Vitamins Vitamins are a vital part of a healthy diet. The recommended dietary allowance (RDA)—the amount most healthy people need each day to remain healthy—has been determined for most vitamins. A safe... read more .)

Carotenoids, such as beta-carotene, are pigments in fruits and vegetables that give them their yellow, orange, or red color. Once consumed, carotenoids are slowly converted to vitamin A in the body. Carotenoids are best absorbed from cooked or homogenized vegetables served with some fat or oil. Good sources of carotenoids are dark green, yellow, and orange vegetables and yellow and orange fruits.

Causes of Vitamin A Deficiency

Vitamin A deficiency is usually caused by

  • A diet that has been deficient in vitamin A for a long time

This deficiency is common in areas of the world where people do not eat enough of foods that are good sources of vitamin A, such as

  • Animal and fish liver

  • Orange, yellow, and dark green vegetables and yellow and orange fruits

  • Eggs

  • Fortified milk products

For example, vitamin A deficiency occurs in southern and eastern Asia, where regular rice, which contains no vitamin A, is the main food. Golden rice has higher amounts of beta carotene, and may decrease vitamin A deficiency.

Vitamin A deficiency is common among people who have had a severe deficiency of protein and calories (protein-energy undernutrition Protein-Energy Undernutrition Undernutrition is a deficiency of calories or of one or more essential nutrients. Undernutrition may develop because people cannot obtain or prepare food, have a disorder that makes eating or... read more Protein-Energy Undernutrition ) for a long time. People with this disorder do not consume enough vitamin A, and storage and use of vitamin A is impaired.

Symptoms of Vitamin A Deficiency

An early symptom of vitamin A deficiency is night blindness, which is caused by a disorder of the retina. Soon thereafter, the whites (conjunctiva) and corneas of the eyes may become dry and thick—a condition called xerophthalmia Keratomalacia Keratomalacia is an eye disorder that involves drying and clouding of the cornea (the clear layer in front of the iris and pupil) due to vitamin A deficiency in people with undernutrition. Vitamin... read more . Xerophthalmia is particularly common among children who have a severe deficiency of calories and protein, which includes inadequate intake of vitamin A. Foamy deposits (Bitot spots) may appear in the whites of the eyes. The dry cornea may soften and deteriorate, and blindness may result. Vitamin A deficiency is a common cause of blindness in developing countries.

The skin becomes dry and scaly, and the lining of the lungs, intestine, and urinary tract thicken and stiffen.

Children’s growth and development may be slowed. More than half of children with severe vitamin A deficiency may die.

Diagnosis of Vitamin A Deficiency

  • A doctor's evaluation

  • Blood tests

  • Relief of symptoms when vitamin A supplements are taken

Doctors suspect vitamin A deficiency based on symptoms, such as night blindness.

Doctors measure the level of vitamin A in the blood. However, levels do not decrease until the deficiency is severe because the body stores large amounts of vitamin A.

To help confirm vitamin A deficiency, doctors may give people vitamin A supplements to see whether they relieve symptoms.

Prevention of Vitamin A Deficiency

To help prevent vitamin A deficiency, people should eat dark green leafy vegetables, yellow and orange fruits (such as papayas and oranges), carrots, and yellow vegetables (such as squash and pumpkin). Other food sources include milk and cereals that are fortified with vitamin A, liver, egg yolks, and fish liver oils. The carotenoids that give fruits and vegetables their yellow, orange, or red color and that are converted to vitamin A in the body, are best absorbed from cooked or homogenized vegetables served with some fat or oil.

Children who live in developing countries and are at risk of vitamin A deficiency should take vitamin A supplements.

Treatment of Vitamin A Deficiency

  • Vitamin A supplements

People who have vitamin A deficiency are given high doses of vitamin A, usually by mouth, for several days, followed by lower doses until vision and skin improve. Infants should not be given high doses repeatedly because such doses can be toxic.

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