Vitamin A is fat soluble retinoid , which is stable to heat, acid and alkali but liable to oxidization. There are two types of vitamin A. The first type named retinol, which is the original form of vitamin A and only comes from animal food. The other type is carotene, which can be ingested from both plant-based food or animal-based food. The conversion efficiency from carotene to retinol varies by person. Vitamin A contains photosensitive substances that help make the retina (i.e. rhodopsin), which is very important for night vision. Vitamin A is also essential for body growth and development and maintaining the skin and mucosa, so that the immune system operates normally.
Source of Vitamin A:
Vitamin A is one of vital vitamins needed in human body, which can be taken through diet.
Health benefits of Vitamin A:
The key physiological functions of vitamin A include:
1.Helps maintain good eyesight
Vitamin A can maintain normal visual response and prevent some eye diseases such as dry eye, night blindness, conjunctivitis, vision loss and age-related macular degeneration.
2.Promotes body growth and development:
Retinol can promote the production of glycoprotein, promote body growth, enhance bone strength, and maintain the health of teeth, gums, skin and hair.
3.Maintain immunity at the normal level
In particular, the body's resistance to respiratory infection and parasitic infection . Vitamin A is conducive to the treatment of hyperthyroidism and emphysema.
4.Keep the epithelial structure intact and healthy
Prevent cornification of dry skin mucous membrane. Vitamin A can treat acne , abscess, skin surface ulcer when used externally.
Vitamin A deficiency
Vitamin A deficiency happens possibly due to insufficient vitamin A in the body, fat absorption disorders or liver diseases. The lack of vitamin A can lead to stunting, impaired immune function and hematopoietic function, cornification of epidermal tissue, dry eye disease, night blindness, and even softened corneal and corneal perforation ,and eventually complete blindness. Treatment should be taken based on each syndromes.
Danger of excessive vitamin A intake
The intake of vitamin A should not surpass the needed amount. A large dose of vitamin A intake (more than 200000 mg) for a single time will cause blurred vision, nausea, vomiting and dizziness; Daily intake of 10000 micrograms vitamin A and over by mouth for a long period will lead to headache, nausea, skin allergy, diarrhea,pain in the joint and bone, birth defects, thinning bone and liver damage.
Vitamin A and influence of common drugs
1. Orlistat reduces the absorption of vitamin A, other fat soluble vitamins and β- Thecarotene as well as the plasma concentration.
2. Retinoids and vitamin A taken together will accumulate excessive amount of vitamin A in the body and cause related side effects.
3. Anticoagulants taken with vitamin A will increase the risk of bleeding.
4. Besarotin taken with vitamin A supplements will add to the probability of side effects, such as itchiness and dry skin.
5. Hepatotoxic drugs taken with high-dose vitamin A may increase the risk of liver disease.
What food provides vitamin A?
Vitamin A is found mainly in animal liver,fish rich in fat, egg yolks, and vegetables containing carotene.
Foods high in vitamin A
- Pork liver
Vitamin A wellness boost products
- Good Deposit – Advance 50+ Multi-Vitamins and Minerals 100 Capsules
- Webber Naturals - Women's Most Complete Multi 90 vegetarian capsules
- Jamieson - Multi for Kids | 60 chewable tablets