What is vitamin A?
Vitamin A is a group of fat-soluble retinoids, nutritional organic compounds that occur naturally in both plant and animal tissues, that play an important role in vision, bone growth, reproduction, cell division and differentiation, and immunity. There are two types of vitamin A that we obtain from diet:
- Animal sources (fish, meat and dairy products) provide preformed vitamin A in the form of retinoic acid, retinal and retinol. They can be used directly by the body.
- Fruits and vegetables provide pro-vitamin A, also known as carotenoids. The most common type is beta-carotene which is found primarily in plants such as carrot and sweet potato. They must be converted by the body into usable retinoids to be utilized, unless body levels are already high.
Vitamin A health benefits:
1. Protects visual system and eyesight
Vitamin A plays a vital role in mammalian eye development; it is required for completing the visual cycle, normal retina functioning, dim-light vision and color vision. Vitamin A is critical for rhodopsin molecule which is needed to see dim-light as well as for night vision, because it is required the reformation of rhodopsin in the retina. A deficiency of vitamin A will lead to thinning and ulceration of the cornea which can result to blindness.
2. Supports skin health
Vitamin A is essential in the synthesis of glycoproteins, a combination of sugar and protein, which help the cells bind together to form soft tissues. It is very important for the normal formation, development and maintenance of the epithelial (surface skin) cells, both internally and externally, such as skin, respiratory tracts, gastrointestinal tracts and so on.
A deficiency of vitamin A could result poor complexion, wrinkles and acne. That’s why vitamin A is always added to skin care products to improve overall skin health.
3. Improves immune system
The normal functioning of the immune system is dependent on sufficient vitamin A, because it’s anti-infective, fighting inflammation and beta-carotene’s antioxidative ability. It is required for body’s first line of defense against infection and free radical attack, including the skin, digestive tracts, and urinary tracts.
4. Prenatal and postnatal development benefits
Pregnant women need vitamin A for fetal growth and support metabolism. A deficiency vitamin A in pregnant and lactating women could lead to increase in infant morbidity and mortality, anemia risk, and slower infant growth.
However, vitamin A excess can cause birth defects. It is very important for pregnant women to advise their physician about the amount of vitamin A intake.
The recommended amount for average adult is 5,000IU (equivalent to 1.5mg). It is more than what RDA suggested to achieve the optimum level of health and disease prevention. Higher levels of beta-carotene may confer extra benefits.
How much of each vitamin you need depends on your age, gender, and tolerable upper intake levels. Also, other factors such as pregnancy and health condition.
Vitamins A food sources
It is recommended to eat five or more servings of fruits and vegetables per day, including dark green and leafy vegetables and deep yellow or orange fruits to get appropriate amounts of beta-carotene.
Foods contain high vitamin A: Carrot, sweet potato, spinach, broccoli, kale, eggs, fish oil, parsley, peppers and animal livers