Vitamin A 

(BETA CAROTENE, RETINOL)
Recommended Dietary Intakes
Men - 750 mcg
Women - 750 mcg

This vitamin is essential for…

Beta carotene which is related to vitamin A, acts either as a precursor to vitamin A or as an antioxidant. It is a natural food substance.
Your skin stores beta carotene and your body metabolises it to produce vitamin A as needed.
It is reported that beta carotene increases your resistance to infection and may help prevent some cancers and vision problems. Beta carotene may also reduce the risk of heart disease.

Sources...

Orange and yellow vegetables and fruits; dark-green leafy vegetables; whole milk, cream, egg yolks and butter; and animal livers, fish liver oils, garlic, and alfalfa.

Comments...

Vitamin A is fat-soluble, and therefore can is stored in the body long-term and supplements are generally not recommended. Too much vitamin A over long periods can cause headaches, vision problems, nausea, vomiting, abdominal pain, dry and flaking skin, or an enlarged liver or spleen.
No overdose can happen with beta-carotene however, as the body controls the conversion of it from this source.

Deficiencies Can Cause...