Vitamin A, also called retinol, is a fat-soluble vitamin. Our bodies store fat-soluble vitamins in the liver and fatty tissues. The active form of vitamin A is found in animal tissue. Red, orange, and dark green vegetables and fruits contain precursor forms of vitamin A called carotenoids. Our bodies can convert some of these carotenoids into vitamin A.
Functions
Here are some of vitamin A's functions:
- Plays an essential role in vision
- Plays an important role in cell differentiation and cell division
- Helps in the formation and maintenance of healthy skin and hair
- Helps with proper bone growth and tooth development
- Helps the body regulate the immune system
- Plays an essential role in the reproduction process for both men and women
Recommended Intake:
The recommended daily dietary allowance for vitamin A is measured in micrograms (mcg) of Retinol Activity Equivalents (RAE).
| Age Group (in years) |
Recommended Dietary Allowance |
| Females |
Males |
| 1 – 3 |
300 mcg of RAE |
300 mcg of RAE |
| 4 – 8 |
400 mcg of RAE |
400 mcg of RAE |
| 9 – 13 |
600 mcg of RAE |
600 mcg of RAE |
| 14 – 18 |
700 mcg of RAE |
900 mcg of RAE |
| 14 – 18 Pregnancy |
750 mcg of RAE |
n/a |
| 14 – 18 Lactation |
1,200 mcg of RAE |
n/a |
| 19+ |
700 mcg of RAE |
900 mcg of RAE |
| 19+ Pregnancy |
770 mcg of RAE |
n/a |
| 19+ Lactation |
1,300 mcg of RAE |
n/a |
Vitamin A Deficiency
Vitamin A deficiency is rare in the US, but it is common in developing countries. Here are some of the symptoms:
- Night blindness
- Decreased resistance to infections
- Decreased growth rate
-
Diarrhea
Vitamin A Toxicity
As a fat-soluble vitamin, vitamin A is stored in the body and not excreted in the urine like most water-soluble vitamins. Therefore, it is possible for vitamin A to accumulate in the body and reach toxic levels. For adults, the tolerable upper intake level (UL) for vitamin A from dietary sources and supplements combined is 3,000 RAE daily. It is less in children. Symptoms of toxicity include the following:
- Nausea
- Vomiting
- Headache
- Blurred vision
- Dizziness
- Poor coordination
Too much vitamin A can cause severe birth defects. Pregnant women, and those who may become pregnant, should not take too much vitamin A from dietary sources and supplements.
Major Food Sources
| Food |
Serving size |
Vitamin A content
(mcg of RAE)
|
| Beef liver, cooked |
3 ounces |
6,582 |
| Milk, fat-free |
8 ounces |
149 |
| Whole egg, boiled |
1 large |
75 |
| Sockeye salmon, cooked |
3 ounces |
59 |
The following foods contain carotenoids, which the body converts into vitamin A.
| Food |
Serving size |
Vitamin A content
(mcg of RAE)
|
| Sweet potato, baked in skin |
1 whole |
1,403 |
| Carrots, raw |
½ cup |
459 |
| Mango, raw |
1 whole |
112 |
| Red bell pepper, raw |
½ cup |
117 |
| Cantaloupe, raw |
½ cup |
135 |
| Apricots, dried, sulfured |
10 halves |
63 |
| Spinach, cooked |
½ cup |
573 |
| Tomato juice, canned |
12 ounces |
42 |
Health Implications
Populations at risk for vitamin A deficiency
The following populations may be at risk for vitamin A deficiency and may require a supplement:
-
People with a reduced ability to absorb dietary fat. Because vitamin A is a fat-soluble vitamin, fat is required for its absorption. Some conditions that can cause fat malabsorption include
Crohn's disease,
cystic fibrosis,
celiac disease, pancreatic enzyme deficiency, and liver disease.
- Children living in developing countries.
Tips for Increasing Your Vitamin A Intake:
Here are some tips to help increase your intake of vitamin A:
- Pack cut carrots in your lunch for an afternoon snack.
- Slice a peach, mango, or apricot on to your breakfast cereal or oatmeal.
- Substitute a sweet potato for your baked potato.
- Eat fruits and vegetables raw whenever possible. Vitamin A can be lost during preparation and cooking.
- Steam vegetables, and braise, bake, or broil meat instead of frying. This will help retain some of the vitamin content.