Vitamin A Fact Sheet

Vitamin A is part of a group of compounds called retinoids and is essential for growth, bone development, night vision, reproduction and healthy skin. It is present in animal products (such as liver), dairy products, eggs and fish liver oil, and is also converted from carotenoids, which are found in dark red, green, and yellow vegetables. Vitamin A is best absorbed when taken with a meal that includes dietary fat.

Average DRI is 875 mcg. Supplements are rarely recommended for people with normal diets because there is risk of toxicity.

Deficiencies of vitamin A
Deficiencies of vitamin A can cause skin disorders and eye damage. In less-developed countries severe deficiencies cause blindness in 250,000 children each year. Diets low in vitamin A may also increase the risk of developing cancer. Deficiencies in the US are rare but can result from inadequate diets (usually in preschool children) or in women who are pregnant or breast-feeding; from intestinal disorders, such as cystic fibrosis, steatorrhea (excessive fat in the stool) and biliary obstruction; from hyperthyroidism; and from cirrhosis of the liver and other liver diseases.

Toxicity of vitamin A
Vitamin A can be very toxic when taken in high-dose supplements for long periods of time. Almost every part of the body can be affected, including eyes, bones, blood, skin, central nervous system, liver, and genital and urinary tracts. Symptoms include dizziness, nausea, vomiting, headache, skin damage, mental disturbances and, in women, infrequent periods. Severe toxicity can cause blindness and may even be life threatening. Liver damage can occur in children who take RDA-approved adult levels over prolonged periods of time, or in adults who take vitamin A in excess (as little as five times the RDA-approved amount). In children, chronic overdose can cause fluid on the brain in addition to other typical symptoms. Pregnant women who increase their intake of vitamin A are at risk for birth defects in their babies. High consumption may also increase a woman’s risk of gastric cancer, osteoporosis and bone fractures.

Although supplements can do us a world of good, remember that just because a product calls itself a vitamin or supplement, that doesn’t necessarily mean it’s good for you. Synthetic vitamins can actually be dangerous, so it’s important to be educated about them.