Vitamin A Benefits, Food Sources, and Health Supplement Recommendations

Vitamin A is the name of a fat-soluble retinoid that is stable to heat, acid, and alkali but easily oxidized. There are two types of vitamin A. One is retinol, which only exists in animal foods and is the original form of vitamin A. The other is carotene, which can be obtained from plant or animal foods. The amount of it converted into retinol in the body varies from person to person. Vitamin A contains photosensitive substances (i.e. rhodopsin) that help produce the retina, which is very important for night vision; it promotes human growth and development; and it maintains normal skin and mucous membranes, allowing the immune system to function normally.

Common uses of vitamin A

Vitamin A is one of the vitamins required by the human body and can be obtained through diet.

Vitamin A Health Benefits

The important physiological functions of vitamin A include:

1. Helps maintain good eyesight

Vitamin A can maintain normal visual response, help relieve dry eyes, maintain healthy night vision, and some eye degenerative problems such as age-related macular degeneration.

2. Promote growth and development

Retinol promotes the production of glycoprotein, which can promote development, make bones stronger, and maintain the health of teeth, gums, skin, and hair.

3. Helps maintain normal immunity

Especially the body's resistance to the respiratory tract, which helps to maintain respiratory health.

4. Can maintain the integrity and soundness of epithelial structure

It prevents dryness and keratinization of the skin and mucous membranes, and external application helps treat acne, pustules, skin surface ulcers, etc.

Vitamin A deficiency

If vitamin A deficiency exists, it may be caused by insufficient vitamin A intake, fat malabsorption or liver problems. Vitamin A deficiency can lead to developmental abnormalities, impaired immune and hematopoietic functions, and can also affect eye health and damage vision.

Excessive intake of vitamin A

Vitamin A should not be taken in excess. A single large dose of vitamin A (more than 200,000 mg) can cause blurred vision, nausea, vomiting, and dizziness. Long-term daily intake of more than 10,000 micrograms of oral vitamin A will cause headaches, nausea, skin allergies, diarrhea, joint and bone pain, birth defects, bone thinning, and liver damage.

Vitamin A and Common Medications

1. Orlistat can reduce the absorption of vitamin A, other fat-soluble vitamins and β-carotene, and reduce their plasma concentrations.
2. Taking retinoids and vitamin A together will result in excessive intake of vitamin A and cause side effects.
3. Taking anticoagulants and vitamin A together will increase the risk of bleeding.
4. Taking bexarotene and vitamin A supplements together may increase the chance of side effects, such as itchy and dry skin.