Vitamin A, a fat-soluble vitamin (the first such vitamin discovered, in 1913, per emedicine.medscape.com) that also is a potent antioxidant, is an essential part of our daily diet, in large part because it is not manufactured by the human body. Our body depends on us to supply it with Vitamin A through what we eat. Vitamin A is important for maintaining the health of our eyes and eyesight, healthy and clear skin, proper bone growth, facilitating cell differentiation and supporting our immune system against infections, especially in the mucous membranes for the digestive, respiratory and urinary tracts.
Three Types of Vitamin AVitamin A comes in two primary forms, per draxe.com: retinols and beta carotene:
- Retinols – the most active form of vitamin A (also known as preformed vitamin A ), retinols are sourced from foods that come from animals and can be used readymade by the body without need for conversion.
- Beta carotene – it is supplied by colorful fruits and vegetables in the form of what is described as pro vitamin A carotenoids, which, draxe.com says, are converted to retinol by the body following our ingestion of food. Beta carotene is found primarily in plants.
Food Sources of Vitamin AEven though it is entirely up to us to be the sole source of vitamin A, there should be little problem of that, at least in the Western world and other developed countries, where an extraordinarily wide range of foods are available, with many of those rich in vitamin A. Among the foods known to provide ample amounts of vitamin A are eggs, milk, liver, fish-liver oils, and yellow or orange vegetables and fruits that include carrots, squash, spinach and other leafy greens, mango, papaya and apricots. Also, some breakfast cereals pastries, bread, crackers and cereal grain bars are fortified with vitamin A. Typically, 80 to 90 percent of the vitamin A in our bodies is stored in our liver, per merckmanuals.com, from where it is released into circulation bound by prealbumin and retinol-binding protein.
Sources and Symptoms of Vitamin A DeficiencyVitamin A deficiency is rarely found in the United States and other developed countries, where well-balanced diets and food sources provide plenty of opportunities for us to consume and ingest vitamin A, even when we aren't aware we are doing so. A deficiency of vitamin A most commonly results from an inadequate intake of vitamin A – vitamin supplements can help in that regard, although fat malabsorption and liver disorders can also be involved in A deficiency, per merckmanuals.com. Those at higher risk of a vitamin A deficiency include people who follow a strict vegan diet, alcoholism, toddlers and preschool children living in poverty, and recent immigrants or refugees from developing countries, per patient.info. Various diseases could be involved, causing interference with absorption or storage of vitamin A: such interference could be the result of celiac disease, cystic fibrosis, pancreatic inefficiency, chronic diarrhea or cirrhosis, among other diseases. One of the early symptoms of vitamin A deficiency is impaired bight vision, where adaptation of the eyes is involved. Another sign is drying and scaling of the skin, as well as respiratory infections. The younger the patient, the more severe the effects, health experts say.
Problems from Vitamin A DeficiencyHere are further details of the health problems linked to a vitamin A deficiency:
- Poor eye health. Such a deficiency can result in a thickening of the cornea as a possible precursor to blindness. The condition is known as keratomalacia, which usually affects both eyes. Your eyesight may be followed by wrinkling, cloudiness, and a softening of the corneas, says draxe.com.
- Respiratory infections. This is where the body's immune system comes into the picture, with immunity hampered by a shortage of vitamin A. The younger the patient, the more serious the problem, with growth retardation and infections common among children without sufficient vitamin A. In the U.S., this is not a time to panic. Instances of vitamin A deficiency, especially a severe deficiency, are rare in America thanks to our (supposedly) well-balanced diets and all that vitamin A included in it.
- Skin damage. It's what is known as keratinization of the skin, when epithelial cells' availability of moisture is lessened, leading to drying, scaling and follicular thickening of the skin.
- Risky pregnancy. The need and demand for vitamin A in pregnant women is at its peak during the third trimester.