Vitamin A plays an important role in vision, reproduction, and bone development. It encourages the growth of health surface linings in the eyes, lungs, intestines, and uninary track.

Vitamin A is a fat soluble vitamin. This means that excess amounts are stored in the liver or in fat cells. Because of this you must be careful not to take too much Vitamin A, as it can become toxic.

The recommended daily allowance (RDA) of vitamin A is 5,000 International Units (IU). A recent study showed that the average adult consumes only about 3,300 IU of vitamin A per day. A daily intake of more than about 10,000 IU of vitamin A can lead to toxic symptoms such as nausea, vomiting, headaches, dizziness, and blurred vision.

Retinol is the most useable form of Vitamin A and can be found in a variety of food products. The animal based foods with the highest concentrations of vitamin A are beef liver (27,000 IU for each 3 ounces serving), chicken liver (12,300 IU for each 3 ounces serving), and fortified skim milk (500 IU per cup). The plant based foods with the highest levels of vitamin A are carrot juice (22,500 IU per cup), boiled carrots (13,400 IU per cup of sliced carrots), and boiled spinach (11,450 IU per cup).

Vitamin A Deficiency

Vitamin A deficiency is extremely rare in the United States and the rest of the developed world. However, somewhere between 250,000 to 500,000 children in the developing world go blind each year from vitamin A deficiency.

Excess consumption of alcohol and zinc deficiency are the most common causes of vitamin A deficiency in the United States. Zinc is needed to help the body process vitamin A. In addition, certain medical problems interfere with fat absorpion, causing a vitamin A deficiency. Those who suffer from celiac disease, Crohn's disease, colitis, or pancratic disorders may need to consider taking a Vitmain A supplement.