What is Vitamin A

Vitamin A

Vitamin A occurs in two forms: preformed vitamin A, known as retinol, and pro vitamin A, also known as beta carotene. Vitamin A is also known as the “vision vitamin” for its role in aiding eyesight. Because it is fat-soluble and stored in the liver, it need not be replenished every day.

Vitamin A helps maintain healthy skin, teeth and bones as well as mucous membranes such as those in the nose, throat and lungs. It is necessary in the formation of an eye pigment involved in night vision, and is therefore essential for vision in dim light. Vitamin A is needed for proper development of the fetus in the womb.

Severe deficiency leads to various physical changes in the eye and will eventually lead to blindness. Marginal deficiency will lead to increased susceptibility to respiratory tract infections and skin problems. Some therapeutic uses is for some skin conditions like acne and psoriasis.

People who are vegetarians, diabetics who can not efficiently convert beta carotene in to vitamin A, those with malabsorption syndromes like celiac disease or gastrectomy patients.

Foods that are rich in vitamin A are halibut liver oil, lamb’s liver, cod liver oil, butter, margarine, cheddar cheese, eggs, Pig’s kidney, milk, mackerel, beef and can sardines.

Taken excessively will result to toxicity because it is stored in the liver. However, it is still has a high safety margin in that regular daily intake generally has to exceed 7,500 mcg in women and 9,000 mcg in men before toxic effects are experienced. The vitamin A toxicity is usually fully reversible. The vitamin A intake of pregnant women should not exceed 3.300 mcg per day ( from food and supplement combined) unless directed by a health care professional.