<unk>  is used to treat vitamin A deficiency. Three approaches may be used when populations have low vitamin A levels: # Through dietary modification involving the adjustment of menu choices of affected persons from available food sources to optimize vitamin A content. # Enriching commonly eaten and affordable foods with vitamin A, a process called fortification. It involves addition of synthetic vitamin A to staple foods like margarine, bread, flours, cereals and other infant formulae during processing # By giving high-doses of vitamin A to the targeted deficient population, a method known as supplementation. Side effects The Tolerable Upper Intake Level (UL) for vitamin A, for a 25-year-old man, is 3,000 micrograms/day, or about 10,000 IU. In breastfeeding mothers, vitamin A intake should be 1,200 to 1,300<unk>  activity units (RAE). Too much vitamin A in<unk> d form can be harmful. The body converts the dimerized form, carotene, into vitamin A as it is needed, so high levels of carotene are not toxic, whereas the ester (animal) forms are. The livers of certain animals, especially those adapted to polar environments, such as polar bears and seals, often contain amounts of vitamin A that would be toxic to humans. Thus, vitamin A toxicity is typically reported in Arctic explorers and people taking large doses of synthetic vitamin A. The first documented death possibly caused by vitamin A poisoning was that of Xavier Mertz, a Swiss scientist, who died in January 1913 on an Antarctic expedition that had lost its food supplies and fell to eating its sled dogs. Mertz may have consumed lethal amounts of vitamin A by eating the dogs' livers. Vitamin A acute toxicity occurs when a person ingests vitamin A in large amounts more than the daily recommended value in the threshold of 25,000 IU/kg or more. Often, the sufferer consumes about 3–4 times the RDA's specification. Toxicity of vitamin A is believed to be associated with the methods of increasing vitamin A in the body, such as food modification, fortification, and supplementation, all of which are used to combat vitamin A deficiency. Toxicity is classified into two categories: acute and chronic. The former occurs a few hours or days after ingestion of a large amount of vitamin A. Chronic toxicity takes place when about 4,000 IU/kg or more of vitamin A is consumed for a long time. Symptoms of both include nausea, blurred vision, fatigue, weight-loss, and menstrual abnormalities. Excess vitamin A is suspected to be a contributor to osteoporosis. This seems to happen at much lower doses than those required to induce acute intoxication. Only preformed vitamin A can cause these problems, because the conversion of carotenoids into vitamin A is downregulated when physiological requirements are met; but excessive uptake of carotenoids can cause carotenosis. Excess preformed vitamin A during early pregnancy is associated with a significant increase in birth defects. These defects may be severe, even life-threatening. Even twice the daily recommended amount can cause severe birth defects. The FDA recommends that pregnant women get their vitamin A from foods containing beta carotene and that they ensure that they consume no more than 5,000 IU of preformed vitamin A (if any) per day. Although vitamin A is necessary for fetal development, most women carry stores of vitamin A in their fat cells, so over-supplementation should be strictly avoided. A review of all randomized controlled trials in the scientific literature by the Cochrane Collaboration published in JAMA in 2007 found that supplementation with beta carotene or vitamin A increased mortality by 5% and 16%, respectively. Studies emerging from developing countries India, Bangladesh, and Indonesia strongly suggest that, in populations in which vitamin A deficiency is common and maternal mortality is high, dosing expectant mothers can greatly reduce maternal mortality. Similarly, dosing newborn infants with 50,000 IU (15 mg) of vitamin A within two days of birth can significantly reduce neonatal mortality.
Retinol
Epoetin beta
Retinoid
Eutropoflavin
Lactitol
Epoetin alfa
Gadobenic acid
Vitamer