Vitamin A is a fat soluble vitamin that consists of the Retinoids which includes retinol which is an alcohol form of Vitamin A and retinal which is the aldehyde form of Vitamin A and retinoic acid which is the acid form of Vitamin A.
Vitamin A helps with our:
Vision – helps our eyes adjust to darkness and bright light.
Proper Growth – lack of Vitamin A causes bones to weaken.
Reproduction – helps with sperm production and maintains fertility.
Immunity – helps maintain healthy epithelial tissues that defend us from bacteria, parasites and viral attack. It also supports the generation of T lymphocytes that respond to attack invading infections.
Cell Differentiation – helps stem cells mature into differentiated cells and also makes skin cells and mucous membranes.
Vitamin A is stored by the liver (it stores more than 90%), is deposited in fat tissue, lungs and kidneys.
Recommended Daily Allowance (RDA)
The recommended daily allowance of vitamin A for males aged 14 and up is 100 micrograms RAE per day.
Women aged 14 and up are recommended to take 700 micrograms RAE per day.
Preggers are recommended to take 770 micrograms RAE per day.
Lactaters are recommended to take 1300 micrograms RAE per day.
Sources of Vitamin A are cooked beef liver, sweet potato, cooked carrots, cooked chicken liver, cooked spinach, raw spinach, cooked collards and raw romaine lettuce. Vegetables that are orange have higher concentrations of beta-carotene and has the highest potential Vitamin A activity.
Fresh watermelon, cooked black-eyed peas, dried plums, cooked green beans, 1%, 2% and nonfat milk are also adequate sources of Vitamin A.
Vitamin A deficiency is rare in the United States. An early sign of deficiency is night blindness. After that, childhood blindness and bone deformities are also signs of deficiency.
Populations that are at-risk for Vitamin A deficiency include newborns, especially if they are premature, impoverished people, especially kids and the elderly, alcoholics, people on certain medications, people with chronic diarrhea, people who have Celiac disease, Chrons disease, Cystic Fibrosis, pancreatic insufficiency and other fat-malabsorption conditions, people who are on severely fat restricted diets, for example, people with anorexia and people with low zinc intake are all at an increased risk of Vitamin A deficiency.
The UI for Vitamin A is 3000 micrograms RAE. Toxicity is infrequent but it happens when people take megadoses of Vitamin A.
Toxicity is not good for people because it causes fatigue, vomiting, abdominal pain, bone and joint pain, appetite loss, skin disorders, headache, blurred or double vision, liver damage and jaundice. Toxicity causes an increased risk for fractures, birth defects such as cleft palate, heart abnormalities and brain malfunction.
Be careful with Vitamin A, it can be dangerous to have too much or too little of this good thing.
USDA.gov. United States Department of Agriculture, 27 Jan. 2012. Web. 27 Jan. 2012. <http://www.fns.usda.gov/tn/Resources/appendd.pdf>.
Insel, Paul M., R. Elaine. Turner, and Don Ross. Nutrition. 3rd ed. Sudbury, MA: Jones and Bartlett, 2007. Print.