why is vitamin a deficiency common in developing countries
Vitamin A deficiency The major cause is roughage which include few animal sources of pre-formed vitamin A.[citation needed] In addition to dietary problems, there are other causes of VAD. Iron deficiency can affect vitamin A uptake. Excess alcohol consumption can deplete vitamin A, and a stressed liver may be more susceptible to vitamin A toxicity. People who consume large amounts of alcohol should seek medical advice before taking vitamin A supplements. In general, people should also seek medical advice before taking vitamin A supplements if they have any condition associated with fat malabsorption such as pancreatitis, cystic fibrosis, tropical sprue and biliary obstruction. Other causes of Vitamin A deficiency are inadequate intake, fat malabsorption, or liver disorders. Deficiency impairs immunity and hematopoiesis and causes rashes and typical ocular effects (e.g., xerophthalmia, night blindness).[17]
Malnutrition Undernourishment is most often due to not enough high-quality food being available to eat.[5] This is often related to high food prices and poverty.[1][5] A lack of breastfeeding may contribute, as may a number of infectious diseases such as: gastroenteritis, pneumonia, malaria, and measles, which increase nutrient requirements.[5] There are two main types of undernutrition: protein-energy malnutrition and dietary deficiencies.[12] Protein-energy malnutrition has two severe forms: marasmus (a lack of protein and calories) and kwashiorkor (a lack of just protein).[2] Common micronutrient deficiencies include: a lack of iron, iodine, and vitamin A.[2] During pregnancy, due to the body's increased need, deficiencies may become more common.[13] In some developing countries, overnutrition in the form of obesity is beginning to present within the same communities as undernutrition.[14] Other causes of malnutrition include anorexia nervosa and bariatric surgery.[15][16]