What role does vitamin A play in the human body?

The fat-soluble compound, vitamin A has a major role in the following functions of the human body:

Vision
Cell division and cell differentiation – determines the assignments of each cell to the brain, lungs, muscle and so forth
Helps regulate the immune system
Prevents or defends against infections by making white blood cells
Supports lymphocytes (a type of white blood cell) fight infections more effectively.
Enhances healthy surface linings of the eyes and the respiratory, urinary, and intestinal tracts
Ensures the integrity of both skin and mucous membranes – by functioning as a barrier to bacteria and viruses
Aids in bone development/growth
Helps in the reproduction process

Retinol is one of the most active, or usable, forms of vitamin A, and is found in animal foods such as liver and whole milk and in some fortified food products. Retinol is also called preformed vitamin A. It can be converted to retinal and retinoic acid, other active forms of the vitamin A family.

Which foods offer vitamin A?

Vitamin A is referred to as retinol. It is an active, resourceful from of vitamin A. Generally, retinol is found in animal foods. Milk, whole eggs, milk, and liver contain retinol; however, most fat-free milk and other solid nonfat milk substitutes in the United States are fortified with vitamin A to replace the volume of lost fat.

Animal food sources of Vitamin A

Liver, beef
Liver, chicken
Milk, fortified skim
Cheese, cheddar
Milk, whole
Egg substitute

Plant sources of vitamin A (from beta-carotene)
Carrot juice
Carrots
Spinach
Kale
Cantaloupe
Apricots with skin
Papaya
Mango
Oatmeal
Peas (frozen or boiled)
Tomato juice
Peaches
Pepper