Vitamin A was first ‘discovered’ in 1913, when scientists found it could prevent night blindness. Then, in 1932 it was determined that beta-carotene, also known as pro-vitamin A, was the precursor to vitamin A. When we consume beta-carotene, vitamin A is produced naturally by enzymes in the digestive tract that digest beta-carotene. The fat-soluble vitamin A is then stored in the liver, where it can remain for long periods of time. Vitamin A occurs naturally only in animal products like liver, kidney, butter, egg yolks, whole milk and fortified skim milk.*
Vitamin D, calciferol, is a fat-soluble vitamin. It is known as the “sunshine” vitamin because it is formed in the body by the action of the sun’s ultraviolet rays on the skin. Vitamin D is converted in the kidneys to the hormone calcitrol, which is actually the most active form of vitamin D. The effects of this hormone are targeted at the intestines and bones. The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, thereby helping to form and maintain strong bones. It promotes bone mineralization in concert with a number of other vitamins, minerals, and hormones.*
*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.