There are two different types of vitamin A:
1- Pre-formed vitamin A (retinol): It is found in meat, organ meats (liver, etc.), poultry (eggs, etc.), fish (salmon, shrimp, etc.) and dairy products (butter, cheese, cheddar, cream, enriched margarine, etc.).
2- Provitamin A: Found in fruits (melon, apricot, mango, papaya), vegetables (green leafy vegetables, green, orange and yellow vegetables such as spinach, broccoli, carrots, sweet potatoes, and pumpkin) and other plant-based products.
The liver is a rich source of vitamin A. Especially during pregnancy, it should not be eaten more than once a week. Contains vitamin A in fortified breakfast cereals.
The type commonly used in foods and supplements is provitamin A type beta carotene. Beta carotene can be easily converted to vitamin A as needed. Carotenoids act as antioxidants, contain protective properties against cataracts, and show effects that reduce the risk of lung cancer.
Vitamin A deficiency is rare. Since vitamin A is stored in the liver, it may take up to 2 years for deficiency symptoms to appear. Night blindness and very dry, rough skin are signs of vitamin A deficiency. Other possible symptoms; It is a decrease in resistance to infections, improper tooth development and slow bone growth. Vitamin A deficiency is a known risk factor for severe measles.
However, some individuals may experience difficulty in vitamin A intake. These; early years of premature babies, infants in developing countries, young children, pregnant and lactating women, individuals with cystic fibrosis.
The most common sign of deficiency is an eye condition called xerophthalmia (poor vision). Not being treated can cause blindness.
It is difficult to get high levels of vitamin A with food alone, but multivitamin supplements contain high doses of vitamin A. Retinol (preformed vitamin A) intake causes high toxicity, harmful to bones.
Consuming beta carotene or other forms of vitamin A can turn skin a yellow-orange color, but it is considered safe. It has been determined that some drugs used to treat acne, psoriasis and other skin conditions contain compounds that mimic retinol in the body, thus negatively affecting bone health and causing growth retardation in children and adolescents.
The recommended daily intake of vitamin A is 700 mcg for women and 900 mcg for men.