Vitamin AVitamin A is a fat-soluble vitamin, also known as retinol because it produces pigments in the eye's retina. The eye needs a specific metabolite - retinal - a light-absorbing substance that is crucial for scotopic vision (low-light vision). Vitamin A is also important for healthy teeth, skeletal tissue, soft tissue, the skin, and mucous membranes.
Vitamin A comes from two main types of foods:
2. the original vitamin A, now known as retinol. Vitamin A deficiency Vitamin A deficiency is common in poor countries and extremely rare in developed nations. Sufferers of night blindness - people who cannot see well in dim light - are more likely to have a vitamin A deficiency. Night blindness is one of the most common signs of vitamin a deficiency. According to WHO (World Health Organization), night blindness among pregnant women in developing nations is worryingly high. Pregnant women with vitamin A deficiency are more likely to die during pregnancy and childbirth, and may have problems with lactation.
People with vitamin A deficiency can also develop xerophthalmia (dry eyes) and even complete blindness. Between 250,000 and 500,000 malnourished children worldwide lose their eyesight each year because they do not have enough vitamin A. Half of them die within twelve months of becoming blind. A child with not enough vitamin A has a higher risk of dying from some infectious diseases, such as measles. Low vitamin A levels make children more susceptible to diarrhea, slow bone development, and respiratory infections. Approximately one third of all children globally are thought to be affected by vitamin A deficiency - 670,000 of whom die within their first five years of life.How much vitamin A should I take?Below are the recommended daily amounts of vitamin A people should take, according to the Institute of Medicine of the National Academies: It is possible to have too much vitamin A, which can lead to anorexia, irritability, abdominal pain, weakness, drowsiness, headaches, hair loss, irritability, dry skin, insomnia, weight loss, bone fractures, diarrhea and anemia. However, intake would have to be extremely high.Good sources of vitamin A Apricots Butter Broccoli leaf Cantaloupe Carrots Cheddar cheese Cod liver oil Collard greens Eggs Fortified cereals Kale Liver Mangos Milk Papayas Peaches Peas Pumpkin Spinach Sweet potatoes. |
Infant aged up to six months - adequate intake 400 μg/day. Upper limit 600 μg/day.
Infant 7 to 12 months - adequate intake 500 μg/day. Upper limit 600 μg/day. Children 1 to 3 years - adequate intake 300 μg/day. Upper limit 600 μg/day. Children 4 to 8 years - adequate intake 400 μg/day. Upper limit 900 μg/day. Males 9 to 13 years - adequate intake 600 μg/day. Upper limit 1,700 μg/day. Males 14 to 18 years - adequate intake 900 μg/day. Upper limit 2,800 μg/day. Males 19 to 70 years - adequate intake 900 μg/day. Upper limit 3,000 μg/day. Females 9 to 13 years - adequate intake 600 μg/day. Upper limit 1700 μg/day. Females 14 to 18 years - adequate intake 700 μg/day. Upper limit 2,800 μg/day. Females 19 to 70 years - adequate intake 700 μg/day. Upper limit 3,000 μg/day. Pregnant women up 19 years - adequate intake 750 μg/day. Upper limit 2,800 μg/day. Pregnant women 19 to 50 years - - adequate intake 770 μg/day. Upper limit 3,000 μg/day. Lactation, up to 19 years - adequate intake 1,200 μg/day. Upper limit 2,800 μg/day. Lactation, 19 to 50 years - adequate intake 1,300 μg/day. Upper limit 3,000 μg/day. |