Vitamin A, the first fat soluble vitamin to be discovered, consists of three forms – retinols, beta carotenes and carotenoids.
Retinol is the most active of the three. Also known as provitamin A, its source is from animal-based foods.
Beta carotene, popularly known as provitamin A, on the other hand, derives its source from plant-based foods. It is through beta carotene that two thirds of mammals make Vitamin A in their bodies.
Carotenoids are the largest among the three groups. It is usually found in a free alcohol or a fatty acyl ester form.
Benefits Of Vitamin A
Vitamin A is important in helping maintain healthy teeth, skin, mucous membrane and skeletal and soft tissue.
It’s well-known for improving vision, especially in dim light. It’s also an important vitamin for a healthy reproductive system and is beneficial to women who breastfeed.
You should be aware of how harmful free radicals are to our bodies. They have a degenerative effect on our tissues and organs. Vitamin A in beta carotene helps generate antioxidants, which are useful in combating free radicals.
Vitamin A also plays an important role in maintaining the health of our respiratory, urinary, and intestinal tracts.
Recommended Daily Allowance (RDA)
The RDAs of Vitamin A are as follows:
- Babies below 1 year – 375 mcg,
- Children from one to three years old – 400mcg
- Children from four to six years old – 500 mcg
- Males more than ten years old – 1000mcg|
- Females more than ten years old – 800mcg
Vitamin A Deficiency and Symptoms
In the United States, vitamin A deficiency is usually found among the elderly, the malnourished, and those who are chronically sick. However, the condition is more prevalent in developing countries where incidences of malnourishment are high.
Among the early signs of Vitamin A deficiency are poor vision in dim light, dry hair, dry skin, brittle fingernails, and low résistance to infections.
Those who are at high risk of Vitamin A deficiency are those suffering from fat malabsorption, cystic fibrosis, pancreatic insufficiency, and those who are recovering from small-bowel bypass surgery. Vegans and alcoholics are also in the high risk group.
Vitamin A Diet
The US Department of Agriculture and Health’s Dietary Guidelines recommends foods that are rich in Vitamin A.
The foods are as listed below:
- whole milk
- fortified milk
- orange fruits
- sweet potatoes
- spinach, kale, and other green vegetables
Further, the Department recommends consumption of fruits and vegetables, at least 5 servings a day to allow for a thorough distribution of carotenoids in the body. Foods such as breakfast cereals, breads, cereal grain bars, and breakfast cereals provide 10 to 15 per cent of the Vitamin A recommended daily allowance (RDA).
https://emedicine.medscape.com/article/126004-overview -vitamin A deficiency, RDA and diet
https://www.online-vitamins-guide.com/vitamins/vitamin-a.htm - benefits of vitamin A