A Vitamin A deficiency slows the thyroid hormone response inside the cell.
You may have a Vitamin A deficiency if you suffer from liver issues, you have night vision difficulties, or you have been found to be iron deficient.
Vitamin A is a fat-soluble vitamin that is naturally present in many foods.
Vitamin A is important for normal vision, the immune system, and reproduction.
Vitamin A also helps the heart, lungs, kidneys, and other organs work properly.
There are two different types of vitamin A.
The first type, preformed vitamin A, is found in meat, poultry, fish, and dairy products.
The second type, provitamin A, is found in fruits, vegetables, and other plant-based products.
The most common type of provitamin A in foods and dietary supplements is beta-carotene.
How much vitamin A do I need?
The amount of vitamin A you need depends on your age and reproductive status.
Recommended intakes for vitamin A for people aged 14 years and older range between 700 and 900 micrograms (mcg) of retinol activity equivalents (RAE) per day. Recommended intakes for women who are nursing range between 1,200 and 1,300 RAE.
Lower values are recommended for infants and children younger than 14.
However, the vitamin A content of foods and dietary supplements is given on product labels in international units (IU), not mcg RAE. Converting between IU and mcg RAE is not easy. A varied diet with 900 mcg RAE of vitamin A, for example, provides between 3,000 and 36,000 IU of vitamin A depending on the foods consumed.
For adults and children aged 4 years and older, the U.S. Food and Drug Administration has established a vitamin A Daily Value (DV) of 5,000 IU from a varied diet of both plant and animal foods. DVs are not recommended intakes; they don’t vary by age and sex, for example. But trying to reach 100% of the DV each day, on average, is useful to help you get enough vitamin A.
What foods provide vitamin A?
Vitamin A is found naturally in many foods and is added to some foods, such as milk and cereal. You can get recommended amounts of vitamin A by eating a variety of foods, including the following:
•Beef liver and other organ meats (but these foods are also high in cholesterol, so limit the amount you eat).
•Some types of fish, such as salmon.
•Green leafy vegetables and other green, orange, and yellow vegetables, such as broccoli, carrots, and squash.
•Fruits, including cantaloupe, apricots, and mangos.
•Dairy products, which are among the major sources of vitamin A for Americans.
•Fortified breakfast cereals.
Upper Limit
Birth to 12 months 2,000 IU
Children 1–3 years 2,000 IU
Children 4–8 years 3,000 IU
Children 9–13 years 5,667 IU
Teens 14–18 years 9,333 IU
Adults 19 years and older 10,000 IU
Am I getting enough vitamin A?
Most people in the United States get enough vitamin A from the foods they eat, and vitamin A deficiency is rare. However, certain groups of people are more likely than others to have trouble getting enough vitamin A:
Vitamin A can be toxic at high doses, causing liver damage and birth defects if a woman is pregnant. However, this applies only to the form of vitamin A—called preformed vitamin A or retinol—that is found in foods from animals, such as beef liver, milk, milk products, and some dietary supplements.
Plant foods, such as carrots, spinach, and red peppers, contain a form of vitamin A called beta-carotene. Consuming high amounts of beta-carotene can turn the skin yellow-orange, but this condition is harmless. Beta-carotene does not cause birth defects or the other more serious effects caused by getting too much preformed vitamin A.
So enjoy plenty of carrots and other fruits and vegetables without worrying about getting too much vitamin A