Vitamin A

All about Vitamin A….

Vitamin A is an essential nutrient for the human body and plays a crucial role in various biological processes. It is a fat-soluble vitamin, meaning it dissolves in fat and is stored in the liver.

It is found in two forms in foods: as retinol, present in foods of animal origin such as meat, fish and dairy products; and as provitamin A, present in foods of plant origin such as orange and dark green fruits and vegetables, since the body can convert it into retinol.

Vitamin A is important for vision, the immune system, reproduction, growth and development of cells and tissues. It is also necessary for the maintenance of the skin and mucous membranes, including the mucosa of the respiratory, digestive and genitourinary tracts.

Vitamin A deficiency can cause night vision problems, dry eyes, dry skin, a weakened immune system, and delayed growth. In severe cases, it can cause blindness and increase the risk of infections.

On the other hand, an excess of vitamin A can also be harmful to health, causing toxicity and side effects such as dizziness, headache, anorexia, fatigue, among others.

It is important to consume adequate amounts of vitamin A through a balanced diet that includes foods rich in this vitamin, and to consult a health professional before taking supplements to avoid possible side effects.

A historical anecdote about vitamin A is known as the «Great Buttermilk Controversy.» In 1903, biochemist and physiologist Wilcock and Funk discovered a substance essential for vision in milk fat, which they called «factor X.» In 1913, Elmer McCollum and his collaborators identified two substances, which they called «A» and «B», that were necessary to prevent blindness in mice.

In 1931, Paul György isolated vitamin A and showed that it was the same substance as the «A» factor discovered by McCollum. However, in 1944, Albert Szent-Györgyi discovered that ascorbic acid (vitamin C) could also prevent night blindness, which led to a controversy over whether it was actually vitamin A that was responsible for the prevention of this disease.

Finally, in the 1950s, vitamin A was confirmed to be essential for vision and growth in humans, ending the controversy and cementing the importance of this vitamin in the human diet.