It’s quite a sensitive & complex subject, as such we will do our best at providing a clear and concise article to clear any doubts you may have.
What Is Vitamin A Deficiency?
Deficiency, or a lack, of vitamin A in your body happens because of a lack of sufficient amounts of vitamin A in your diet. Over time, a lack of vitamin A means that you may develop problems with vision and be less able to fight infections.
Night blindness may also occur as a result of vitamin A deficiency.
This causes the person to be unable to see or have trouble seeing in low light, eventually leading to complete blindness at night. The World Health Organization (WHO) note that night blindness is one of the first signs of vitamin A deficiency. In severe cases, the eye continues to dry out, and tissues may build up in the cornea.
A person with a vitamin A deficiency may experience more frequent infections, as they cannot fight off these infections as easily. Some may experience similar issues on the hair and scalp as well.
Causes Of Vitamin A Deficiency
Iciency is night blindness, which is caused by a disorder of the retina.
Soon thereafter, the whites (conjunctiva) and corneas of the eyes may become dry and thick—a condition called xerophthalmia Keratomalacia Keratomalacia is an eye disorder that involves drying and clouding of the cornea (the clear layer in front of the iris and pupil) due to vitamin A deficiency in people with undernutrition.
Vitamin A is the name of a group of fat-soluble retinoids, including retinol, retinal, and retinyl esters [1-3]. Vitamin A also supports cell growth and differentiation, playing a critical role in the normal formation and maintenance of the heart, lungs, kidneys, and other organs .
Two forms of vitamin A are available in the human diet: preformed vitamin A (retinol and its esterified form, retinyl ester) and provitamin A carotenoids [1-5]. Both provitamin A and preformed vitamin A must be metabolized intracellularly to retinal and retinoic acid, the active forms of vitamin A, to support the vitamin’s important biological functions [2,3]. Other carotenoids found in food, such as lycopene, lutein, and zeaxanthin, are not converted into vitamin A.
The various forms of vitamin A are solubilized into micelles in the intestinal lumen and absorbed by duodenal mucosal cells . However, their value for assessing marginal vitamin A status is limited because they do not decline until vitamin A levels in the liver are almost depleted . Liver vitamin A reserves can be measured indirectly through the relative dose-response test, in which plasma retinol levels are measured before and after the administration of a small amount of vitamin A .
A plasma retinol concentration lower than 0.70 micromoles/L (or 20 micrograms [mcg]/dL) reflects vitamin A inadequacy in a population, and concentrations of 0.70–1.05 micromoles/L could be marginal in some people . In some studies, high plasma or serum concentrations of some provitamin A carotenoids have been associated with a lower risk of various health outcomes, but these studies have not definitively demonstrated that this relationship is causal.